🕷️ Crawler Inspector

URL Lookup

Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 40 (from laksa065)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa040.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://www.mayoclinic.org/diseases-conditions/history-disease-outbreaks-vaccine-timeline/covid-19\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.mayoclinic.org/diseases-conditions/history-disease-outbreaks-vaccine-timeline/covid-19\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.mayoclinic.org\/diseases-conditions\/history-disease-outbreaks-vaccine-timeline\/covid-19","crawl_time":1775015686,"first_indexed_time":1685130322,"http_code":200,"src_unparsed":"org,mayoclinic!www,\/diseases-conditions\/history-disease-outbreaks-vaccine-timeline\/covid-19 s443","src_root_hash":"1608882045018104440","history_drop_reason":null,"meta_title":"History of COVID-19: Outbreaks and vaccine timeline","meta_descriptions":["Learn about the COVID-19 pandemic as well as mRNA research, COVID-19 tests and treatments, and COVID-19 vaccine development and approval."],"attrs_boilerpipe_text":"2020\nCOVID-19 and related vaccine development and research\nFind out more about the COVID-19 pandemic, COVID-19 tests, COVID-19 treatments, mRNA research and COVID-19 vaccines.\nThe virus that causes COVID-19\nSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19\n1984\nPaul A. Krieg, Ph.D., Douglas A. Melton, Ph.D., Tom Maniatis, Ph.D., and Michael Green, Ph.D., and colleagues at Harvard University use a synthesized RNA enzyme to make biologically active messenger RNA (mRNA) in a lab. A similar process is still used today to make synthetic mRNA. Drs. Krieg and Melton use synthetic mRNA to study gene function and activity. Other researchers also study RNA.\n1987\nRobert W. Malone, M.D., M.S., mixes mRNA with fat droplets. He discovers that when human cells are added to this mixture, they absorb the mRNA and make proteins. Dr. Malone also finds that frog embryos absorb mRNA. These experiments are considered early steps in the eventual development of mRNA-based COVID-19 vaccines.\n1990s\nResearchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice.\n2000s\nSeveral researchers study mRNA treatments or vaccines. But since mRNA is easy to damage and expensive to produce, many researchers can’t get funding to pursue this work and so the research often wasn’t pursued.\n2005\nKatalin Kariko, Ph.D., and Drew Weissman, M.D., Ph.D., discover that modifying synthetic mRNA keeps the immune system from attacking the mRNA. This discovery moves mRNA vaccine research forward.\n2010s\nMany researchers study mRNA treatments or vaccines.\n2019\nA new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in China. The SARS-CoV-2 virus causes \ncoronavirus disease 2019 (COVID-19)\n. WHO will declare the COVID-19 outbreak a pandemic in 2020. WHO and CDC issue recommendations for preventing and treating COVID-19. By January 2021, COVID-19 will cause about 2.5 million deaths worldwide.\n2020\nMany COVID-19 vaccine clinical trials are in process. Researchers take what was previously learned from vaccine studies of SARS-CoV, MERS-CoV and other viruses to develop \nvaccines\n that prevent COVID-19. Researchers also study \nCOVID-19 symptoms\n, \nlong-term effects\n, \ndiagnostic tests\n, \nantibody tests\n, treatments and \ndrugs\n.\nMayo Clinic researchers study and develop a COVID-19 diagnostic test, an antibody test, monoclonal antibody medications, \nconvalescent plasma therapy\n and vaccines.\nCOVID-19 vaccines\nIn the U.S., the Food and Drug Administration (FDA) gives emergency use authorization to two mRNA\nCOVID-19 vaccines\n, the Pfizer-BioNTech and the Moderna COVID-19 vaccines. Because there is an urgent need for COVID-19 vaccines and the FDA’s vaccine approval process can take months to years, the FDA first gives emergency use authorization to COVID-19 vaccines based on less data than is normally required. However, data must show that the vaccines are safe and effective before the FDA can give emergency use authorization or approval. Vaccines have gone through — and continue to go through — extensive safety monitoring. From December 2020 to December 2025, billions of COVID-19 vaccines are given.\nResearchers at Mayo Clinic and other medical centers continue to study more about COVID-19 vaccines.\nCOVID-19 vaccine\nA child wearing a mask gets a COVID-19 vaccine.\n2021\nThe FDA gives emergency use authorization to the Janssen\/Johnson & Johnson COVID-19 vaccine. The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 16 and older. The FDA authorizes the Pfizer-BioNTech vaccine for\nchildren\nages 5 through 15. Researchers continue to study and develop several other COVID-19 vaccines. Many COVID-19 vaccines are in clinical trials. \n2022\nThe FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 6 months to 4 years and the Moderna vaccine for children ages 6 months to 17 years. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized for people age 12 and older. \n2023\nThe FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Pfizer-BioNTech vaccine for people age 6 months to 11 years. The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Moderna vaccine for children 6 months to 11 years.\n2024\nCertain strains of the COVID-19 virus are targeted in the 2024-2025 COVID-19 vaccines based on the virus strains that are spreading. These include the Pfizer- BioNTech, Moderna and Novavax COVID-19 2024-2025 formula vaccines. The Novavax COVID-19 vaccine, adjuvanted, 2024-2025 formula is authorized for people age 12 and older.\n2025\nThe 2025-2026 COVID-19 vaccines available in the United States include Moderna, Pfizer-BioNTech and Novavax. The vaccines are all approved for people age 65 and older. Each vaccine also is approved for younger people with a health condition that raises the risk of serious COVID-19 illness.\nLearn more:\nPlotkin SA, et al., eds. Plotkin's Vaccines. 7th ed. Elsevier; 2018. \nhttps:\/\/www.clinicalkey.com\n. Accessed Oct. 8, 2021.\nBlake JB. Benjamin Waterhouse and the introduction of vaccination. Reviews of Infectious Diseases. Oxford University Press. 1987;doi:10.1093\/clinids\/9.5.1044.\nDesmond A, et al. On the shoulders of giants — From Jenner’s cowpox to mRNA Covid vaccines. The New England Journal of Medicine. 2021; doi:10.1056\/NEJMp2034334.\nSaleh A, et al. Vaccine development throughout history. Cureus. 2021; doi:10.7759\/cureus.16635.\nThe history of vaccines. College of Physicians of Philadelphia. \nhttps:\/\/www.historyofvaccines.org\n. Accessed Oct. 7, 2021.\nStokes J, et al. Trivalent combined measles-mumps-rubella vaccine. JAMA. 1971;218:57.\nKlein NP. Licensed pertussis vaccine in the United States: History and current state. 2014; doi:10.4161\/hv.29576.\nInfluenza historic timeline. Centers for Disease Control and Prevention. \nhttps:\/\/archive.cdc.gov\/www_cdc_gov\/flu\/pandemic-resources\/pandemic-timeline-1930-and-beyond.htm\n. Accessed Nov. 14, 2024.\nPoland GA, et al. Development of vaccines against Zika virus. The Lancet. Infectious Diseases. 2018; doi:10.1016\/S1473-3099(18)30063-X.\nPoland GA, et al. Zika vaccine development: Current status. Mayo Clinic Proceedings. 2019; doi:10.1016\/j.mayocp.2019.05.016.\nLi YD, et al. Coronavirus vaccine development: From SARS and MERS to COVID-19. Journal of Biomedical Science. 2020; doi:10.1186\/s12929-020-00695-2.\nDolgin E. The tangled history of mRNA vaccines. Nature. 2021; doi:10.1038\/d41586-021-02483-w.\nGoodman RA, et al., eds. Vaccination mandates: The public health imperative and individual rights. In: Law in Public Health Practice. Oxford University Press; 2007.\nCenters for Disease Control and Prevention. Current trends childhood immunization initiative, United States — 5-year follow up. MMWR Morbidity and Mortality Weekly Report. 1982; \nhttp:\/\/www.cdc.gov\/mmwr\/preview\/mmwrhtml\/00001091.htm\n. Accessed Oct. 7, 2021.\nVaccination. Office of Disease Prevention and Health Promotion. https:\/\/ odphp.health.gov\/healthypeople\/objectives-and-data\/browse-objectives\/vaccination. Accessed Nov. 13, 2024.\nThe history of vaccines. History of the immunization schedule. College of Physicians of Philadelphia. https:\/\/ historyofvaccines.org\/activities\/history-immunization-schedule. Accessed Nov. 13, 2024.\nNCIRD national surveillance materials and resources. Centers for Disease Control and Prevention. \nhttps:\/\/www.cdc.gov\/ncird-surveillance\/resources\/index.html\n. Accessed Nov. 13, 2024.\nRoush SW, et al. Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. JAMA. 2007; doi:10.1001\/jama.298.18.2155.\nPoland GA (expert opinion). Mayo Clinic. Sept. 17, 2021.\nFDA approves and authorizes updated mRNA COVID-19 vaccines to better protect against currently circulating variants. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/news-events\/press-announcements\/fda-approves-and-authorizes-updated-mrna-covid-19-vaccines-better-protect-against-currently. Accessed Dec. 6, 2024.\n1918 pandemic influenza timeline. Centers for Disease Control and Prevention. https:\/\/ archive.cdc.gov\/www_cdc_gov\/flu\/pandemic-resources\/1918-commemoration\/pandemic-timeline-1918.htm. Accessed Nov. 14, 2024.\nRecommendations for COVID-19 vaccines in infants, children, and adolescents: Policy statement. Pediatrics. 2025;doi:10.1542\/peds.2025-073924.\nMedical review (expert opinion). Mayo Clinic. Sept. 25, 2025.\nCOVID-19 vaccines. U.S. Food and Drug Administration. \nhttps:\/\/www.fda.gov\/emergency-preparedness-and-response\/coronavirus-disease-2019-covid-19\/covid-19-vaccines\n. Accessed Dec. 2, 2024.\nPoland GA, et al. The age-old struggle against the antivaccinationists. The New England Journal of Medicine. 2011; doi:10.1056\/NEJMp1010594.\nClapesattle H. The Doctors Mayo. The University of Minnesota Press; 1941.\nSaint Mary's isolation hospital during the influenza pandemic. Saint Marys Hospital Annals; 1918.\nHarren R. Olmsted country in the grippe of Spanish influenza. The Scribe. History Center of Olmsted Country. 2018.\nStrand PK. A Century of Caring: 1889-1989. Saint Marys Hospital; 1988.\nMayo Clinic: The battle plan for H1N1. Mayo Alumni Magazine; 2009.\nFirst polio vaccine delivery. MayoVox. Mayo Clinic; 1955.\nRosenow EC. Prophylactic inoculation against respiratory infections during the present pandemic of influenza: Preliminary report. Mayo Clinic; 1918.\nRules concerning the report of contagious diseases. The Clinic Bulletin. 1919;1;1.\nMaltezou HA, et al. Immunization of health-care providers: Necessity and public-health policies. Healthcare. 2016; doi:10.3390\/healthcare4030047.\nVoigt EA, et al. Defending against smallpox: A focus on vaccines. Expert Review of Vaccines. 2016; doi:10.1080\/14760584.2016.1175305.\nWright GH, et al. Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: A randomized trial. Vaccine. 2014; doi:10.1016\/j.vaccine.2013.10.039.\nSpikevax. U.S. Food and Drug Administration. \nhttps:\/\/www.fda.gov\/vaccines-blood-biologics\/spikevax\n. Accessed Dec. 2, 2024.\nInfectious Disease. Office of Disease Prevention and Health Promotion. https:\/\/ odphp.health.gov\/healthypeople\/objectives-and-data\/browse-objectives\/infectious-disease. Accessed Nov. 13, 2024.\nCoronavirus disease (COVID-19). World Health Organization. \nhttps:\/\/www.who.int\/news-room\/fact-sheets\/detail\/coronavirus-disease-(covid-19)\n. Accessed Nov. 27, 2024.\nSpikevax (approval letter). Biologic License Application 125752. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/spikevax. Accessed Sept. 25, 2025.\nMnexspike (approval letter). Biologic License Application 125835 U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/mnexspike. Accessed Sept. 25, 2025.\nComirnaty (approval letter). Biologic License Application 125742. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/comirnaty. Accessed Sept. 25, 2025.\nNuvaxovid (approval letter). Biologic License Application 125817. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/vaccines\/nuvaxovid. Accessed Sept. 25, 2025.\nAskMayoExpert. COVID-19 vaccination. Mayo Clinic; 2025.","attrs_markdown":"[Skip to content](https:\/\/www.mayoclinic.org\/diseases-conditions\/history-disease-outbreaks-vaccine-timeline\/covid-19#main-content)\n\n[![Mayo Clinic Home Page](https:\/\/assets.mayoclinic.org\/content\/dam\/mayoclinic\/images\/logos\/mayo-clinic-logo.svg)](https:\/\/www.mayoclinic.org\/)\n\n- Care at Mayo Clinic\n  [Patient-Centered Care](https:\/\/www.mayoclinic.org\/patient-centered-care)\n  \n  [About Mayo Clinic](https:\/\/www.mayoclinic.org\/about-mayo-clinic)\n  \n  [Request Appointment](https:\/\/www.mayoclinic.org\/appointments)\n  \n  [Find a Doctor](https:\/\/www.mayoclinic.org\/appointments\/find-a-doctor)\n  \n  [Locations](https:\/\/www.mayoclinic.org\/locations)\n  \n  [Clinical Trials](https:\/\/www.mayo.edu\/research\/clinical-trials)\n  \n  [Connect to Support Groups](https:\/\/connect.mayoclinic.org\/)\n  \n  [Patient & Visitor Guide](https:\/\/www.mayoclinic.org\/patient-visitor-guide)\n  \n  [Billing & 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![](https:\/\/assets.mayoclinic.org\/content\/dam\/media\/global\/images\/2023\/10\/23\/giving-to-mayo-em100063715-p-195580295-415x275.png)\n\n# 2020COVID-19 and related vaccine development and research\n## History of COVID-19: Outbreaks and vaccine timeline\n**Find out more about the COVID-19 pandemic, COVID-19 tests, COVID-19 treatments, mRNA research and COVID-19 vaccines.**\n\n![Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19](https:\/\/assets.mayoclinic.org\/content\/dam\/media\/global\/images\/2025\/history-disease-outbreaks-vaccine-timeline\/coronavirus2-structure-2208x1472-1668678_3931480-001.jpg)\n\nThe virus that causes COVID-19\n\nSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19\n\n## 1984\nPaul A. Krieg, Ph.D., Douglas A. Melton, Ph.D., Tom Maniatis, Ph.D., and Michael Green, Ph.D., and colleagues at Harvard University use a synthesized RNA enzyme to make biologically active messenger RNA (mRNA) in a lab. A similar process is still used today to make synthetic mRNA. Drs. Krieg and Melton use synthetic mRNA to study gene function and activity. Other researchers also study RNA.\n\n## 1987\nRobert W. Malone, M.D., M.S., mixes mRNA with fat droplets. He discovers that when human cells are added to this mixture, they absorb the mRNA and make proteins. Dr. Malone also finds that frog embryos absorb mRNA. These experiments are considered early steps in the eventual development of mRNA-based COVID-19 vaccines.\n\n## 1990s\nResearchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice.\n\n## 2000s\nSeveral researchers study mRNA treatments or vaccines. But since mRNA is easy to damage and expensive to produce, many researchers can’t get funding to pursue this work and so the research often wasn’t pursued.\n\n## 2005\nKatalin Kariko, Ph.D., and Drew Weissman, M.D., Ph.D., discover that modifying synthetic mRNA keeps the immune system from attacking the mRNA. This discovery moves mRNA vaccine research forward.\n\n## 2010s\nMany researchers study mRNA treatments or vaccines.\n\n## 2019\nA new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in China. The SARS-CoV-2 virus causes [coronavirus disease 2019 (COVID-19)](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/symptoms-causes\/syc-20479963). WHO will declare the COVID-19 outbreak a pandemic in 2020. WHO and CDC issue recommendations for preventing and treating COVID-19. By January 2021, COVID-19 will cause about 2.5 million deaths worldwide.\n\n## 2020\nMany COVID-19 vaccine clinical trials are in process. Researchers take what was previously learned from vaccine studies of SARS-CoV, MERS-CoV and other viruses to develop [vaccines](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-vaccine\/art-20484859) that prevent COVID-19. Researchers also study [COVID-19 symptoms](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/symptoms-causes\/syc-20479963), [long-term effects](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-long-term-effects\/art-20490351), [diagnostic tests](https:\/\/www.mayoclinic.org\/tests-procedures\/covid-19-diagnostic-test\/about\/pac-20488900), [antibody tests](https:\/\/www.mayoclinic.org\/tests-procedures\/covid-19-antibody-testing\/about\/pac-20489696), treatments and [drugs](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/expert-answers\/coronavirus-drugs\/faq-20485627).\n\nMayo Clinic researchers study and develop a COVID-19 diagnostic test, an antibody test, monoclonal antibody medications, [convalescent plasma therapy](http:\/\/www.mayoclinic.org\/tests-procedures\/convalescent-plasma-therapy\/about\/pac-20486440) and vaccines.\n\n### COVID-19 vaccines\nIn the U.S., the Food and Drug Administration (FDA) gives emergency use authorization to two mRNA [COVID-19 vaccines](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-vaccine\/art-20484859), the Pfizer-BioNTech and the Moderna COVID-19 vaccines. Because there is an urgent need for COVID-19 vaccines and the FDA’s vaccine approval process can take months to years, the FDA first gives emergency use authorization to COVID-19 vaccines based on less data than is normally required. However, data must show that the vaccines are safe and effective before the FDA can give emergency use authorization or approval. Vaccines have gone through — and continue to go through — extensive safety monitoring. From December 2020 to December 2025, billions of COVID-19 vaccines are given.\n\nResearchers at Mayo Clinic and other medical centers continue to study more about COVID-19 vaccines.\n\n![ A young child wearing a mask gets a COVID-19 vaccine from a health care professional wearing a mask and face shield.](https:\/\/assets.mayoclinic.org\/content\/dam\/media\/global\/images\/2025\/history-disease-outbreaks-vaccine-timeline\/child-covid-vax-2208x1472-Getty-1306490855.jpg)\n\nCOVID-19 vaccine\n\nA child wearing a mask gets a COVID-19 vaccine.\n\n## 2021\nThe FDA gives emergency use authorization to the Janssen\/Johnson & Johnson COVID-19 vaccine. The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 16 and older. The FDA authorizes the Pfizer-BioNTech vaccine for [children](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/covid-19-vaccines-for-kids\/art-20513332) ages 5 through 15. Researchers continue to study and develop several other COVID-19 vaccines. Many COVID-19 vaccines are in clinical trials.\n\n## 2022\nThe FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 6 months to 4 years and the Moderna vaccine for children ages 6 months to 17 years. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized for people age 12 and older.\n\n## 2023\nThe FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Pfizer-BioNTech vaccine for people age 6 months to 11 years. The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Moderna vaccine for children 6 months to 11 years.\n\n## 2024\nCertain strains of the COVID-19 virus are targeted in the 2024-2025 COVID-19 vaccines based on the virus strains that are spreading. These include the Pfizer- BioNTech, Moderna and Novavax COVID-19 2024-2025 formula vaccines. The Novavax COVID-19 vaccine, adjuvanted, 2024-2025 formula is authorized for people age 12 and older.\n\n## 2025\nThe 2025-2026 COVID-19 vaccines available in the United States include Moderna, Pfizer-BioNTech and Novavax. The vaccines are all approved for people age 65 and older. Each vaccine also is approved for younger people with a health condition that raises the risk of serious COVID-19 illness.\n## Learn more:\n- COVID-19 vaccines\n  - [COVID-19 vaccines: Get the facts](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-vaccine\/art-20484859)\n  - [Comparing the differences between COVID-19 vaccines](https:\/\/www.mayoclinic.org\/diseases-conditions\/comparing-vaccines)\n  - [Mayo Clinic expert discusses updated COVID-19 vaccines](https:\/\/newsnetwork.mayoclinic.org\/discussion\/mayo-clinic-expert-discusses-updated-covid-19-vaccines\/)\n  - [mRNA vaccines and immunity (video)](https:\/\/www.mayoclinic.org\/mrna-vaccines-immunity\/vid-20507649)\n  - [Different types of COVID-19 vaccines: How they work](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/different-types-of-covid-19-vaccines\/art-20506465)\n  - [Mayo Clinic expert discusses updated COVID-19 vaccines](https:\/\/newsnetwork.mayoclinic.org\/discussion\/mayo-clinic-expert-discusses-updated-covid-19-vaccines\/)\n  - [Vector and Viral Engineering Lab](http:\/\/www.mayo.edu\/research\/labs\/vector-vaccine-engineering)\n- COVID-19 vaccines and kids\n  - [COVID-19 vaccines for kids: What you need to know](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/covid-19-vaccines-for-kids\/art-20513332)\n  - [Mayo Clinic Minute: 3 misconceptions about COVID-19 and flu vaccines](https:\/\/newsnetwork.mayoclinic.org\/discussion\/mayo-clinic-minute-3-misconceptions-about-covid-19-and-the-flu-vaccines\/)\n- COVID-19 treatment\n  - [COVID-19 drugs: Are there any that work?](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/expert-answers\/coronavirus-drugs\/faq-20485627)\n  - [Treating COVID-19 at home: Care tips for you and others](http:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/treating-covid-19-at-home\/art-20483273)\n- COVID-19 tests\n  - [COVID-19 diagnostic testing](https:\/\/www.mayoclinic.org\/tests-procedures\/covid-19-diagnostic-test\/about\/pac-20488900)\n  - [COVID-19 antibody testing](https:\/\/www.mayoclinic.org\/tests-procedures\/covid-19-antibody-testing\/about\/pac-20489696)\n  - [How testing has kept up with new COVID-19 variants](https:\/\/newsnetwork.mayoclinic.org\/discussion\/how-testing-has-kept-up-with-new-covid-19-variants\/)\n\nHistory of infectious disease outbreaks and vaccines timeline.\n\nLearn about the history of major disease outbreaks, epidemics and pandemics, as well as the impact vaccines and research had on many infectious diseases.\n\nFind out more at [History of infectious disease outbreaks and vaccines timeline](https:\/\/www.mayoclinic.org\/diseases-conditions\/history-disease-outbreaks-vaccine-timeline).\n\nShow References\n\n1. Plotkin SA, et al., eds. Plotkin's Vaccines. 7th ed. Elsevier; 2018. [https:\/\/www.clinicalkey.com](https:\/\/www.clinicalkey.com\/). Accessed Oct. 8, 2021.\n2. Blake JB. Benjamin Waterhouse and the introduction of vaccination. Reviews of Infectious Diseases. Oxford University Press. 1987;doi:10.1093\/clinids\/9.5.1044.\n3. Desmond A, et al. On the shoulders of giants — From Jenner’s cowpox to mRNA Covid vaccines. The New England Journal of Medicine. 2021; doi:10.1056\/NEJMp2034334.\n4. Saleh A, et al. Vaccine development throughout history. Cureus. 2021; doi:10.7759\/cureus.16635.\n5. The history of vaccines. College of Physicians of Philadelphia. [https:\/\/www.historyofvaccines.org](https:\/\/www.historyofvaccines.org\/). Accessed Oct. 7, 2021.\n6. Stokes J, et al. Trivalent combined measles-mumps-rubella vaccine. JAMA. 1971;218:57.\n7. Klein NP. Licensed pertussis vaccine in the United States: History and current state. 2014; doi:10.4161\/hv.29576.\n8. Influenza historic timeline. Centers for Disease Control and Prevention. <https:\/\/archive.cdc.gov\/www_cdc_gov\/flu\/pandemic-resources\/pandemic-timeline-1930-and-beyond.htm>. Accessed Nov. 14, 2024.\n9. Poland GA, et al. Development of vaccines against Zika virus. The Lancet. Infectious Diseases. 2018; doi:10.1016\/S1473-3099(18)30063-X.\n10. Poland GA, et al. Zika vaccine development: Current status. Mayo Clinic Proceedings. 2019; doi:10.1016\/j.mayocp.2019.05.016.\n11. Li YD, et al. Coronavirus vaccine development: From SARS and MERS to COVID-19. Journal of Biomedical Science. 2020; doi:10.1186\/s12929-020-00695-2.\n12. Dolgin E. The tangled history of mRNA vaccines. Nature. 2021; doi:10.1038\/d41586-021-02483-w.\n13. Goodman RA, et al., eds. Vaccination mandates: The public health imperative and individual rights. In: Law in Public Health Practice. Oxford University Press; 2007.\n14. Centers for Disease Control and Prevention. Current trends childhood immunization initiative, United States — 5-year follow up. MMWR Morbidity and Mortality Weekly Report. 1982; <http:\/\/www.cdc.gov\/mmwr\/preview\/mmwrhtml\/00001091.htm>. Accessed Oct. 7, 2021.\n15. Vaccination. Office of Disease Prevention and Health Promotion. https:\/\/ odphp.health.gov\/healthypeople\/objectives-and-data\/browse-objectives\/vaccination. Accessed Nov. 13, 2024.\n16. The history of vaccines. History of the immunization schedule. College of Physicians of Philadelphia. https:\/\/ historyofvaccines.org\/activities\/history-immunization-schedule. Accessed Nov. 13, 2024.\n17. NCIRD national surveillance materials and resources. Centers for Disease Control and Prevention. <https:\/\/www.cdc.gov\/ncird-surveillance\/resources\/index.html>. Accessed Nov. 13, 2024.\n18. Roush SW, et al. Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. JAMA. 2007; doi:10.1001\/jama.298.18.2155.\n19. Poland GA (expert opinion). Mayo Clinic. Sept. 17, 2021.\n20. FDA approves and authorizes updated mRNA COVID-19 vaccines to better protect against currently circulating variants. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/news-events\/press-announcements\/fda-approves-and-authorizes-updated-mrna-covid-19-vaccines-better-protect-against-currently. Accessed Dec. 6, 2024.\n21. 1918 pandemic influenza timeline. Centers for Disease Control and Prevention. https:\/\/ archive.cdc.gov\/www\\_cdc\\_gov\/flu\/pandemic-resources\/1918-commemoration\/pandemic-timeline-1918.htm. Accessed Nov. 14, 2024.\n22. Recommendations for COVID-19 vaccines in infants, children, and adolescents: Policy statement. Pediatrics. 2025;doi:10.1542\/peds.2025-073924.\n23. Medical review (expert opinion). Mayo Clinic. Sept. 25, 2025.\n24. COVID-19 vaccines. U.S. Food and Drug Administration. <https:\/\/www.fda.gov\/emergency-preparedness-and-response\/coronavirus-disease-2019-covid-19\/covid-19-vaccines>. Accessed Dec. 2, 2024.\n25. Poland GA, et al. The age-old struggle against the antivaccinationists. The New England Journal of Medicine. 2011; doi:10.1056\/NEJMp1010594.\n26. Clapesattle H. The Doctors Mayo. The University of Minnesota Press; 1941.\n27. Saint Mary's isolation hospital during the influenza pandemic. Saint Marys Hospital Annals; 1918.\n28. Harren R. Olmsted country in the grippe of Spanish influenza. The Scribe. History Center of Olmsted Country. 2018.\n29. Strand PK. A Century of Caring: 1889-1989. Saint Marys Hospital; 1988.\n30. Mayo Clinic: The battle plan for H1N1. Mayo Alumni Magazine; 2009.\n31. First polio vaccine delivery. MayoVox. Mayo Clinic; 1955.\n32. Rosenow EC. Prophylactic inoculation against respiratory infections during the present pandemic of influenza: Preliminary report. Mayo Clinic; 1918.\n33. Rules concerning the report of contagious diseases. The Clinic Bulletin. 1919;1;1.\n34. Maltezou HA, et al. Immunization of health-care providers: Necessity and public-health policies. Healthcare. 2016; doi:10.3390\/healthcare4030047.\n35. Voigt EA, et al. Defending against smallpox: A focus on vaccines. Expert Review of Vaccines. 2016; doi:10.1080\/14760584.2016.1175305.\n36. Wright GH, et al. Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: A randomized trial. Vaccine. 2014; doi:10.1016\/j.vaccine.2013.10.039.\n37. Spikevax. U.S. Food and Drug Administration. <https:\/\/www.fda.gov\/vaccines-blood-biologics\/spikevax>. Accessed Dec. 2, 2024.\n38. Infectious Disease. Office of Disease Prevention and Health Promotion. https:\/\/ odphp.health.gov\/healthypeople\/objectives-and-data\/browse-objectives\/infectious-disease. Accessed Nov. 13, 2024.\n39. Coronavirus disease (COVID-19). World Health Organization. <https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/coronavirus-disease-(covid-19)>. Accessed Nov. 27, 2024.\n40. Spikevax (approval letter). Biologic License Application 125752. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/spikevax. Accessed Sept. 25, 2025.\n41. Mnexspike (approval letter). Biologic License Application 125835 U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/mnexspike. Accessed Sept. 25, 2025.\n42. Comirnaty (approval letter). Biologic License Application 125742. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/comirnaty. Accessed Sept. 25, 2025.\n43. Nuvaxovid (approval letter). Biologic License Application 125817. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/vaccines\/nuvaxovid. Accessed Sept. 25, 2025.\n44. AskMayoExpert. COVID-19 vaccination. 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[Terms & Conditions](https:\/\/www.mayoclinic.org\/about-this-site\/terms-conditions-use-policy)\n- [Privacy Policy](https:\/\/www.mayoclinic.org\/about-this-site\/privacy-policy)\n- [Notice of Privacy Practices](https:\/\/mcforms.mayo.edu\/mc5200-mc5299\/mc5256-01.pdf)\n- [Notice of Nondiscrimination](https:\/\/mcforms.mayo.edu\/mc2500-mc2599\/mc2570-61.pdf)\n- [Digital Accessibility Statement](https:\/\/www.mayoclinic.org\/about-this-site\/accessibility-statement)\n- [Advertising & Sponsorship Policy](https:\/\/www.mayoclinic.org\/about-this-site\/advertising-sponsorship-policy)\n- [Site Map](https:\/\/www.mayoclinic.org\/site-help\/site-map)\n- [Manage Cookies](https:\/\/www.mayoclinic.org\/)\n\n- [Terms and Conditions](https:\/\/www.mayoclinic.org\/about-this-site\/terms-conditions-use-policy)\n- [Privacy Policy](https:\/\/www.mayoclinic.org\/about-this-site\/privacy-policy)\n- [Notice of Privacy Practices](https:\/\/mcforms.mayo.edu\/mc5200-mc5299\/mc5256-01.pdf)\n- [Notice of Nondiscrimination](https:\/\/mcforms.mayo.edu\/mc2500-mc2599\/mc2570-61.pdf)\n- [Digital Accessibility Statement](https:\/\/www.mayoclinic.org\/about-this-site\/accessibility-statement)\n- [Advertising and Sponsorship Policy](https:\/\/www.mayoclinic.org\/about-this-site\/advertising-sponsorship-policy)\n- [Site Map](https:\/\/www.mayoclinic.org\/site-help\/site-map)\n- [Manage Cookies](https:\/\/www.mayoclinic.org\/)\n***\nLanguage:\n\nEnglish\n\n- [English](https:\/\/www.mayoclinic.org\/diseases-conditions\/history-disease-outbreaks-vaccine-timeline\/covid-19)\n- [Español](https:\/\/www.mayoclinic.org\/es)\n- [العربية](https:\/\/www.mayoclinic.org\/ar)\n- [简体中文](https:\/\/www.mayoclinic.org\/zh-hans)\n\n© 1998-2026 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.\n\nLanguage:\n\nEnglish\n\n- [English](https:\/\/www.mayoclinic.org\/diseases-conditions\/history-disease-outbreaks-vaccine-timeline\/covid-19)\n- [Español](https:\/\/www.mayoclinic.org\/es)\n- [العربية](https:\/\/www.mayoclinic.org\/ar)\n- [简体中文](https:\/\/www.mayoclinic.org\/zh-hans)","attrs_readable_markdown":"2020COVID-19 and related vaccine development and research\n\n**Find out more about the COVID-19 pandemic, COVID-19 tests, COVID-19 treatments, mRNA research and COVID-19 vaccines.**\n\n![Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19](https:\/\/assets.mayoclinic.org\/content\/dam\/media\/global\/images\/2025\/history-disease-outbreaks-vaccine-timeline\/coronavirus2-structure-2208x1472-1668678_3931480-001.jpg)\n\nThe virus that causes COVID-19\n\nSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19\n\n1984\n\nPaul A. Krieg, Ph.D., Douglas A. Melton, Ph.D., Tom Maniatis, Ph.D., and Michael Green, Ph.D., and colleagues at Harvard University use a synthesized RNA enzyme to make biologically active messenger RNA (mRNA) in a lab. A similar process is still used today to make synthetic mRNA. Drs. Krieg and Melton use synthetic mRNA to study gene function and activity. Other researchers also study RNA.\n\n1987\n\nRobert W. Malone, M.D., M.S., mixes mRNA with fat droplets. He discovers that when human cells are added to this mixture, they absorb the mRNA and make proteins. Dr. Malone also finds that frog embryos absorb mRNA. These experiments are considered early steps in the eventual development of mRNA-based COVID-19 vaccines.\n\n1990s\n\nResearchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice.\n\n2000s\n\nSeveral researchers study mRNA treatments or vaccines. But since mRNA is easy to damage and expensive to produce, many researchers can’t get funding to pursue this work and so the research often wasn’t pursued.\n\n2005\n\nKatalin Kariko, Ph.D., and Drew Weissman, M.D., Ph.D., discover that modifying synthetic mRNA keeps the immune system from attacking the mRNA. This discovery moves mRNA vaccine research forward.\n\n2010s\n\nMany researchers study mRNA treatments or vaccines.\n\n2019\n\nA new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in China. The SARS-CoV-2 virus causes [coronavirus disease 2019 (COVID-19)](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/symptoms-causes\/syc-20479963). WHO will declare the COVID-19 outbreak a pandemic in 2020. WHO and CDC issue recommendations for preventing and treating COVID-19. By January 2021, COVID-19 will cause about 2.5 million deaths worldwide.\n\n2020\n\nMany COVID-19 vaccine clinical trials are in process. Researchers take what was previously learned from vaccine studies of SARS-CoV, MERS-CoV and other viruses to develop [vaccines](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-vaccine\/art-20484859) that prevent COVID-19. Researchers also study [COVID-19 symptoms](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/symptoms-causes\/syc-20479963), [long-term effects](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-long-term-effects\/art-20490351), [diagnostic tests](https:\/\/www.mayoclinic.org\/tests-procedures\/covid-19-diagnostic-test\/about\/pac-20488900), [antibody tests](https:\/\/www.mayoclinic.org\/tests-procedures\/covid-19-antibody-testing\/about\/pac-20489696), treatments and [drugs](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/expert-answers\/coronavirus-drugs\/faq-20485627).\n\nMayo Clinic researchers study and develop a COVID-19 diagnostic test, an antibody test, monoclonal antibody medications, [convalescent plasma therapy](http:\/\/www.mayoclinic.org\/tests-procedures\/convalescent-plasma-therapy\/about\/pac-20486440) and vaccines.\n\n### COVID-19 vaccines\nIn the U.S., the Food and Drug Administration (FDA) gives emergency use authorization to two mRNA [COVID-19 vaccines](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/coronavirus-vaccine\/art-20484859), the Pfizer-BioNTech and the Moderna COVID-19 vaccines. Because there is an urgent need for COVID-19 vaccines and the FDA’s vaccine approval process can take months to years, the FDA first gives emergency use authorization to COVID-19 vaccines based on less data than is normally required. However, data must show that the vaccines are safe and effective before the FDA can give emergency use authorization or approval. Vaccines have gone through — and continue to go through — extensive safety monitoring. From December 2020 to December 2025, billions of COVID-19 vaccines are given.\n\nResearchers at Mayo Clinic and other medical centers continue to study more about COVID-19 vaccines.\n\n![ A young child wearing a mask gets a COVID-19 vaccine from a health care professional wearing a mask and face shield.](https:\/\/assets.mayoclinic.org\/content\/dam\/media\/global\/images\/2025\/history-disease-outbreaks-vaccine-timeline\/child-covid-vax-2208x1472-Getty-1306490855.jpg)\n\nCOVID-19 vaccine\n\nA child wearing a mask gets a COVID-19 vaccine.\n\n2021\n\nThe FDA gives emergency use authorization to the Janssen\/Johnson & Johnson COVID-19 vaccine. The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 16 and older. The FDA authorizes the Pfizer-BioNTech vaccine for [children](https:\/\/www.mayoclinic.org\/diseases-conditions\/coronavirus\/in-depth\/covid-19-vaccines-for-kids\/art-20513332) ages 5 through 15. Researchers continue to study and develop several other COVID-19 vaccines. Many COVID-19 vaccines are in clinical trials.\n\n2022\n\nThe FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 6 months to 4 years and the Moderna vaccine for children ages 6 months to 17 years. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized for people age 12 and older.\n\n2023\n\nThe FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Pfizer-BioNTech vaccine for people age 6 months to 11 years. The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Moderna vaccine for children 6 months to 11 years.\n\n2024\n\nCertain strains of the COVID-19 virus are targeted in the 2024-2025 COVID-19 vaccines based on the virus strains that are spreading. These include the Pfizer- BioNTech, Moderna and Novavax COVID-19 2024-2025 formula vaccines. The Novavax COVID-19 vaccine, adjuvanted, 2024-2025 formula is authorized for people age 12 and older.\n\n2025\n\nThe 2025-2026 COVID-19 vaccines available in the United States include Moderna, Pfizer-BioNTech and Novavax. The vaccines are all approved for people age 65 and older. Each vaccine also is approved for younger people with a health condition that raises the risk of serious COVID-19 illness.\n\nLearn more:\n\n1. Plotkin SA, et al., eds. Plotkin's Vaccines. 7th ed. Elsevier; 2018. [https:\/\/www.clinicalkey.com](https:\/\/www.clinicalkey.com\/). Accessed Oct. 8, 2021.\n2. Blake JB. Benjamin Waterhouse and the introduction of vaccination. Reviews of Infectious Diseases. Oxford University Press. 1987;doi:10.1093\/clinids\/9.5.1044.\n3. Desmond A, et al. On the shoulders of giants — From Jenner’s cowpox to mRNA Covid vaccines. The New England Journal of Medicine. 2021; doi:10.1056\/NEJMp2034334.\n4. Saleh A, et al. Vaccine development throughout history. Cureus. 2021; doi:10.7759\/cureus.16635.\n5. The history of vaccines. College of Physicians of Philadelphia. [https:\/\/www.historyofvaccines.org](https:\/\/www.historyofvaccines.org\/). Accessed Oct. 7, 2021.\n6. Stokes J, et al. Trivalent combined measles-mumps-rubella vaccine. JAMA. 1971;218:57.\n7. Klein NP. Licensed pertussis vaccine in the United States: History and current state. 2014; doi:10.4161\/hv.29576.\n8. Influenza historic timeline. Centers for Disease Control and Prevention. <https:\/\/archive.cdc.gov\/www_cdc_gov\/flu\/pandemic-resources\/pandemic-timeline-1930-and-beyond.htm>. Accessed Nov. 14, 2024.\n9. Poland GA, et al. Development of vaccines against Zika virus. The Lancet. Infectious Diseases. 2018; doi:10.1016\/S1473-3099(18)30063-X.\n10. Poland GA, et al. Zika vaccine development: Current status. Mayo Clinic Proceedings. 2019; doi:10.1016\/j.mayocp.2019.05.016.\n11. Li YD, et al. Coronavirus vaccine development: From SARS and MERS to COVID-19. Journal of Biomedical Science. 2020; doi:10.1186\/s12929-020-00695-2.\n12. Dolgin E. The tangled history of mRNA vaccines. Nature. 2021; doi:10.1038\/d41586-021-02483-w.\n13. Goodman RA, et al., eds. Vaccination mandates: The public health imperative and individual rights. In: Law in Public Health Practice. Oxford University Press; 2007.\n14. Centers for Disease Control and Prevention. Current trends childhood immunization initiative, United States — 5-year follow up. MMWR Morbidity and Mortality Weekly Report. 1982; <http:\/\/www.cdc.gov\/mmwr\/preview\/mmwrhtml\/00001091.htm>. Accessed Oct. 7, 2021.\n15. Vaccination. Office of Disease Prevention and Health Promotion. https:\/\/ odphp.health.gov\/healthypeople\/objectives-and-data\/browse-objectives\/vaccination. Accessed Nov. 13, 2024.\n16. The history of vaccines. History of the immunization schedule. College of Physicians of Philadelphia. https:\/\/ historyofvaccines.org\/activities\/history-immunization-schedule. Accessed Nov. 13, 2024.\n17. NCIRD national surveillance materials and resources. Centers for Disease Control and Prevention. <https:\/\/www.cdc.gov\/ncird-surveillance\/resources\/index.html>. Accessed Nov. 13, 2024.\n18. Roush SW, et al. Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. JAMA. 2007; doi:10.1001\/jama.298.18.2155.\n19. Poland GA (expert opinion). Mayo Clinic. Sept. 17, 2021.\n20. FDA approves and authorizes updated mRNA COVID-19 vaccines to better protect against currently circulating variants. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/news-events\/press-announcements\/fda-approves-and-authorizes-updated-mrna-covid-19-vaccines-better-protect-against-currently. Accessed Dec. 6, 2024.\n21. 1918 pandemic influenza timeline. Centers for Disease Control and Prevention. https:\/\/ archive.cdc.gov\/www\\_cdc\\_gov\/flu\/pandemic-resources\/1918-commemoration\/pandemic-timeline-1918.htm. Accessed Nov. 14, 2024.\n22. Recommendations for COVID-19 vaccines in infants, children, and adolescents: Policy statement. Pediatrics. 2025;doi:10.1542\/peds.2025-073924.\n23. Medical review (expert opinion). Mayo Clinic. Sept. 25, 2025.\n24. COVID-19 vaccines. U.S. Food and Drug Administration. <https:\/\/www.fda.gov\/emergency-preparedness-and-response\/coronavirus-disease-2019-covid-19\/covid-19-vaccines>. Accessed Dec. 2, 2024.\n25. Poland GA, et al. The age-old struggle against the antivaccinationists. The New England Journal of Medicine. 2011; doi:10.1056\/NEJMp1010594.\n26. Clapesattle H. The Doctors Mayo. The University of Minnesota Press; 1941.\n27. Saint Mary's isolation hospital during the influenza pandemic. Saint Marys Hospital Annals; 1918.\n28. Harren R. Olmsted country in the grippe of Spanish influenza. The Scribe. History Center of Olmsted Country. 2018.\n29. Strand PK. A Century of Caring: 1889-1989. Saint Marys Hospital; 1988.\n30. Mayo Clinic: The battle plan for H1N1. Mayo Alumni Magazine; 2009.\n31. First polio vaccine delivery. MayoVox. Mayo Clinic; 1955.\n32. Rosenow EC. Prophylactic inoculation against respiratory infections during the present pandemic of influenza: Preliminary report. Mayo Clinic; 1918.\n33. Rules concerning the report of contagious diseases. The Clinic Bulletin. 1919;1;1.\n34. Maltezou HA, et al. Immunization of health-care providers: Necessity and public-health policies. Healthcare. 2016; doi:10.3390\/healthcare4030047.\n35. Voigt EA, et al. Defending against smallpox: A focus on vaccines. Expert Review of Vaccines. 2016; doi:10.1080\/14760584.2016.1175305.\n36. Wright GH, et al. Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: A randomized trial. Vaccine. 2014; doi:10.1016\/j.vaccine.2013.10.039.\n37. Spikevax. U.S. Food and Drug Administration. <https:\/\/www.fda.gov\/vaccines-blood-biologics\/spikevax>. Accessed Dec. 2, 2024.\n38. Infectious Disease. Office of Disease Prevention and Health Promotion. https:\/\/ odphp.health.gov\/healthypeople\/objectives-and-data\/browse-objectives\/infectious-disease. Accessed Nov. 13, 2024.\n39. Coronavirus disease (COVID-19). World Health Organization. <https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/coronavirus-disease-(covid-19)>. Accessed Nov. 27, 2024.\n40. Spikevax (approval letter). Biologic License Application 125752. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/spikevax. Accessed Sept. 25, 2025.\n41. Mnexspike (approval letter). Biologic License Application 125835 U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/mnexspike. Accessed Sept. 25, 2025.\n42. Comirnaty (approval letter). Biologic License Application 125742. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/comirnaty. Accessed Sept. 25, 2025.\n43. Nuvaxovid (approval letter). Biologic License Application 125817. U.S. Food and Drug Administration. https:\/\/www.fda.gov\/vaccines-blood-biologics\/vaccines\/nuvaxovid. Accessed Sept. 25, 2025.\n44. AskMayoExpert. COVID-19 vaccination. Mayo Clinic; 2025.","meta_canonical":null}

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Boilerpipe Text	2020 COVID-19 and related vaccine development and research Find out more about the COVID-19 pandemic, COVID-19 tests, COVID-19 treatments, mRNA research and COVID-19 vaccines. The virus that causes COVID-19 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19 1984 Paul A. Krieg, Ph.D., Douglas A. Melton, Ph.D., Tom Maniatis, Ph.D., and Michael Green, Ph.D., and colleagues at Harvard University use a synthesized RNA enzyme to make biologically active messenger RNA (mRNA) in a lab. A similar process is still used today to make synthetic mRNA. Drs. Krieg and Melton use synthetic mRNA to study gene function and activity. Other researchers also study RNA. 1987 Robert W. Malone, M.D., M.S., mixes mRNA with fat droplets. He discovers that when human cells are added to this mixture, they absorb the mRNA and make proteins. Dr. Malone also finds that frog embryos absorb mRNA. These experiments are considered early steps in the eventual development of mRNA-based COVID-19 vaccines. 1990s Researchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice. 2000s Several researchers study mRNA treatments or vaccines. But since mRNA is easy to damage and expensive to produce, many researchers can’t get funding to pursue this work and so the research often wasn’t pursued. 2005 Katalin Kariko, Ph.D., and Drew Weissman, M.D., Ph.D., discover that modifying synthetic mRNA keeps the immune system from attacking the mRNA. This discovery moves mRNA vaccine research forward. 2010s Many researchers study mRNA treatments or vaccines. 2019 A new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in China. The SARS-CoV-2 virus causes coronavirus disease 2019 (COVID-19) . WHO will declare the COVID-19 outbreak a pandemic in 2020. WHO and CDC issue recommendations for preventing and treating COVID-19. By January 2021, COVID-19 will cause about 2.5 million deaths worldwide. 2020 Many COVID-19 vaccine clinical trials are in process. Researchers take what was previously learned from vaccine studies of SARS-CoV, MERS-CoV and other viruses to develop vaccines that prevent COVID-19. Researchers also study COVID-19 symptoms , long-term effects , diagnostic tests , antibody tests , treatments and drugs . Mayo Clinic researchers study and develop a COVID-19 diagnostic test, an antibody test, monoclonal antibody medications, convalescent plasma therapy and vaccines. COVID-19 vaccines In the U.S., the Food and Drug Administration (FDA) gives emergency use authorization to two mRNA COVID-19 vaccines , the Pfizer-BioNTech and the Moderna COVID-19 vaccines. Because there is an urgent need for COVID-19 vaccines and the FDA’s vaccine approval process can take months to years, the FDA first gives emergency use authorization to COVID-19 vaccines based on less data than is normally required. However, data must show that the vaccines are safe and effective before the FDA can give emergency use authorization or approval. Vaccines have gone through — and continue to go through — extensive safety monitoring. From December 2020 to December 2025, billions of COVID-19 vaccines are given. Researchers at Mayo Clinic and other medical centers continue to study more about COVID-19 vaccines. COVID-19 vaccine A child wearing a mask gets a COVID-19 vaccine. 2021 The FDA gives emergency use authorization to the Janssen/Johnson & Johnson COVID-19 vaccine. The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 16 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 5 through 15. Researchers continue to study and develop several other COVID-19 vaccines. Many COVID-19 vaccines are in clinical trials. 2022 The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 6 months to 4 years and the Moderna vaccine for children ages 6 months to 17 years. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized for people age 12 and older. 2023 The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Pfizer-BioNTech vaccine for people age 6 months to 11 years. The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Moderna vaccine for children 6 months to 11 years. 2024 Certain strains of the COVID-19 virus are targeted in the 2024-2025 COVID-19 vaccines based on the virus strains that are spreading. These include the Pfizer- BioNTech, Moderna and Novavax COVID-19 2024-2025 formula vaccines. The Novavax COVID-19 vaccine, adjuvanted, 2024-2025 formula is authorized for people age 12 and older. 2025 The 2025-2026 COVID-19 vaccines available in the United States include Moderna, Pfizer-BioNTech and Novavax. The vaccines are all approved for people age 65 and older. Each vaccine also is approved for younger people with a health condition that raises the risk of serious COVID-19 illness. Learn more: Plotkin SA, et al., eds. Plotkin's Vaccines. 7th ed. Elsevier; 2018. https://www.clinicalkey.com . Accessed Oct. 8, 2021. Blake JB. Benjamin Waterhouse and the introduction of vaccination. Reviews of Infectious Diseases. Oxford University Press. 1987;doi:10.1093/clinids/9.5.1044. Desmond A, et al. On the shoulders of giants — From Jenner’s cowpox to mRNA Covid vaccines. The New England Journal of Medicine. 2021; doi:10.1056/NEJMp2034334. Saleh A, et al. Vaccine development throughout history. Cureus. 2021; doi:10.7759/cureus.16635. The history of vaccines. College of Physicians of Philadelphia. https://www.historyofvaccines.org . Accessed Oct. 7, 2021. Stokes J, et al. Trivalent combined measles-mumps-rubella vaccine. JAMA. 1971;218:57. Klein NP. Licensed pertussis vaccine in the United States: History and current state. 2014; doi:10.4161/hv.29576. Influenza historic timeline. Centers for Disease Control and Prevention. https://archive.cdc.gov/www_cdc_gov/flu/pandemic-resources/pandemic-timeline-1930-and-beyond.htm . Accessed Nov. 14, 2024. Poland GA, et al. Development of vaccines against Zika virus. The Lancet. Infectious Diseases. 2018; doi:10.1016/S1473-3099(18)30063-X. Poland GA, et al. Zika vaccine development: Current status. Mayo Clinic Proceedings. 2019; doi:10.1016/j.mayocp.2019.05.016. Li YD, et al. Coronavirus vaccine development: From SARS and MERS to COVID-19. Journal of Biomedical Science. 2020; doi:10.1186/s12929-020-00695-2. Dolgin E. The tangled history of mRNA vaccines. Nature. 2021; doi:10.1038/d41586-021-02483-w. Goodman RA, et al., eds. Vaccination mandates: The public health imperative and individual rights. In: Law in Public Health Practice. Oxford University Press; 2007. Centers for Disease Control and Prevention. Current trends childhood immunization initiative, United States — 5-year follow up. MMWR Morbidity and Mortality Weekly Report. 1982; http://www.cdc.gov/mmwr/preview/mmwrhtml/00001091.htm . Accessed Oct. 7, 2021. Vaccination. Office of Disease Prevention and Health Promotion. https:// odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/vaccination. Accessed Nov. 13, 2024. The history of vaccines. History of the immunization schedule. College of Physicians of Philadelphia. https:// historyofvaccines.org/activities/history-immunization-schedule. Accessed Nov. 13, 2024. NCIRD national surveillance materials and resources. Centers for Disease Control and Prevention. https://www.cdc.gov/ncird-surveillance/resources/index.html . Accessed Nov. 13, 2024. Roush SW, et al. Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. JAMA. 2007; doi:10.1001/jama.298.18.2155. Poland GA (expert opinion). Mayo Clinic. Sept. 17, 2021. FDA approves and authorizes updated mRNA COVID-19 vaccines to better protect against currently circulating variants. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/fda-approves-and-authorizes-updated-mrna-covid-19-vaccines-better-protect-against-currently. Accessed Dec. 6, 2024. 1918 pandemic influenza timeline. Centers for Disease Control and Prevention. https:// archive.cdc.gov/www_cdc_gov/flu/pandemic-resources/1918-commemoration/pandemic-timeline-1918.htm. Accessed Nov. 14, 2024. Recommendations for COVID-19 vaccines in infants, children, and adolescents: Policy statement. Pediatrics. 2025;doi:10.1542/peds.2025-073924. Medical review (expert opinion). Mayo Clinic. Sept. 25, 2025. COVID-19 vaccines. U.S. Food and Drug Administration. https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/covid-19-vaccines . Accessed Dec. 2, 2024. Poland GA, et al. The age-old struggle against the antivaccinationists. The New England Journal of Medicine. 2011; doi:10.1056/NEJMp1010594. Clapesattle H. The Doctors Mayo. The University of Minnesota Press; 1941. Saint Mary's isolation hospital during the influenza pandemic. Saint Marys Hospital Annals; 1918. Harren R. Olmsted country in the grippe of Spanish influenza. The Scribe. History Center of Olmsted Country. 2018. Strand PK. A Century of Caring: 1889-1989. Saint Marys Hospital; 1988. Mayo Clinic: The battle plan for H1N1. Mayo Alumni Magazine; 2009. First polio vaccine delivery. MayoVox. Mayo Clinic; 1955. Rosenow EC. Prophylactic inoculation against respiratory infections during the present pandemic of influenza: Preliminary report. Mayo Clinic; 1918. Rules concerning the report of contagious diseases. The Clinic Bulletin. 1919;1;1. Maltezou HA, et al. Immunization of health-care providers: Necessity and public-health policies. Healthcare. 2016; doi:10.3390/healthcare4030047. Voigt EA, et al. Defending against smallpox: A focus on vaccines. Expert Review of Vaccines. 2016; doi:10.1080/14760584.2016.1175305. Wright GH, et al. Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: A randomized trial. Vaccine. 2014; doi:10.1016/j.vaccine.2013.10.039. Spikevax. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/spikevax . Accessed Dec. 2, 2024. Infectious Disease. Office of Disease Prevention and Health Promotion. https:// odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/infectious-disease. Accessed Nov. 13, 2024. Coronavirus disease (COVID-19). World Health Organization. https://www.who.int/news-room/fact-sheets/detail/coronavirus-disease-(covid-19) . Accessed Nov. 27, 2024. Spikevax (approval letter). Biologic License Application 125752. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/spikevax. Accessed Sept. 25, 2025. Mnexspike (approval letter). Biologic License Application 125835 U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/mnexspike. Accessed Sept. 25, 2025. Comirnaty (approval letter). Biologic License Application 125742. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/comirnaty. Accessed Sept. 25, 2025. Nuvaxovid (approval letter). Biologic License Application 125817. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/vaccines/nuvaxovid. Accessed Sept. 25, 2025. AskMayoExpert. COVID-19 vaccination. Mayo Clinic; 2025.
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Research & Education at Mayo Clinic ## Research [Research at Mayo Clinic](https://www.mayo.edu/research) [Research Faculty](https://www.mayo.edu/research/faculty) [Laboratories](https://www.mayo.edu/research/labs) [Core Facilities](https://www.mayo.edu/research/core-facilities/overview) [Centers & Programs](https://www.mayo.edu/research/centers-programs) [Departments & Divisions](https://www.mayo.edu/research/departments-divisions) [Clinical Trials](https://www.mayo.edu/research/clinical-trials) [Institutional Review Board](https://www.mayo.edu/research/institutional-review-board/overview) [Postdoctoral Fellowships](https://jobs.mayoclinic.org/search-jobs/postdoctoral%20fellowships/33647/1) [Training Grant Programs](https://www.mayo.edu/research/training-grant-programs) ## Education [Mayo Clinic College of Medicine and Science](https://college.mayo.edu/) [Mayo Clinic Graduate School of Biomedical Sciences](https://college.mayo.edu/academics/biomedical-research-training/) [Mayo Clinic Alix School of Medicine](https://college.mayo.edu/academics/mayo-clinic-alix-school-of-medicine/) [Mayo Clinic School of Graduate Medical Education](https://college.mayo.edu/academics/residencies-and-fellowships/) [Mayo Clinic School of Health Sciences](https://college.mayo.edu/academics/health-sciences-education/) [Mayo Clinic School of Continuous Professional Development](https://ce.mayo.edu/) [Mayo Clinic College of Medicine and Science](https://college.mayo.edu/) ![](https://assets.mayoclinic.org/content/dam/media/global/images/2023/06/26/mccms-Getty-1082003662-415x275.jpg) - Giving to Mayo Clinic [Give Now](https://give.mayoclinic.org/campaign/740556/donate) [Giving to Mayo Clinic](https://www.mayoclinic.org/giving-to-mayo-clinic) [Frequently Asked Questions](https://www.mayoclinic.org/giving-to-mayo-clinic/contact-us/frequently-asked-questions) [Contact Us to Give](https://www.mayoclinic.org/giving-to-mayo-clinic/contact-us) [Make a Donation](https://give.mayoclinic.org/campaign/740556/donate) ![](https://assets.mayoclinic.org/content/dam/media/global/images/2023/10/23/giving-to-mayo-em100063715-p-195580295-415x275.png) # 2020COVID-19 and related vaccine development and research ## History of COVID-19: Outbreaks and vaccine timeline Find out more about the COVID-19 pandemic, COVID-19 tests, COVID-19 treatments, mRNA research and COVID-19 vaccines. ![Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19](https://assets.mayoclinic.org/content/dam/media/global/images/2025/history-disease-outbreaks-vaccine-timeline/coronavirus2-structure-2208x1472-1668678_3931480-001.jpg) The virus that causes COVID-19 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19 ## 1984 Paul A. Krieg, Ph.D., Douglas A. Melton, Ph.D., Tom Maniatis, Ph.D., and Michael Green, Ph.D., and colleagues at Harvard University use a synthesized RNA enzyme to make biologically active messenger RNA (mRNA) in a lab. A similar process is still used today to make synthetic mRNA. Drs. Krieg and Melton use synthetic mRNA to study gene function and activity. Other researchers also study RNA. ## 1987 Robert W. Malone, M.D., M.S., mixes mRNA with fat droplets. He discovers that when human cells are added to this mixture, they absorb the mRNA and make proteins. Dr. Malone also finds that frog embryos absorb mRNA. These experiments are considered early steps in the eventual development of mRNA-based COVID-19 vaccines. ## 1990s Researchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice. ## 2000s Several researchers study mRNA treatments or vaccines. But since mRNA is easy to damage and expensive to produce, many researchers can’t get funding to pursue this work and so the research often wasn’t pursued. ## 2005 Katalin Kariko, Ph.D., and Drew Weissman, M.D., Ph.D., discover that modifying synthetic mRNA keeps the immune system from attacking the mRNA. This discovery moves mRNA vaccine research forward. ## 2010s Many researchers study mRNA treatments or vaccines. ## 2019 A new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in China. The SARS-CoV-2 virus causes [coronavirus disease 2019 (COVID-19)](https://www.mayoclinic.org/diseases-conditions/coronavirus/symptoms-causes/syc-20479963). WHO will declare the COVID-19 outbreak a pandemic in 2020. WHO and CDC issue recommendations for preventing and treating COVID-19. By January 2021, COVID-19 will cause about 2.5 million deaths worldwide. ## 2020 Many COVID-19 vaccine clinical trials are in process. Researchers take what was previously learned from vaccine studies of SARS-CoV, MERS-CoV and other viruses to develop [vaccines](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-vaccine/art-20484859) that prevent COVID-19. Researchers also study [COVID-19 symptoms](https://www.mayoclinic.org/diseases-conditions/coronavirus/symptoms-causes/syc-20479963), [long-term effects](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-long-term-effects/art-20490351), [diagnostic tests](https://www.mayoclinic.org/tests-procedures/covid-19-diagnostic-test/about/pac-20488900), [antibody tests](https://www.mayoclinic.org/tests-procedures/covid-19-antibody-testing/about/pac-20489696), treatments and [drugs](https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/coronavirus-drugs/faq-20485627). Mayo Clinic researchers study and develop a COVID-19 diagnostic test, an antibody test, monoclonal antibody medications, [convalescent plasma therapy](http://www.mayoclinic.org/tests-procedures/convalescent-plasma-therapy/about/pac-20486440) and vaccines. ### COVID-19 vaccines In the U.S., the Food and Drug Administration (FDA) gives emergency use authorization to two mRNA [COVID-19 vaccines](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-vaccine/art-20484859), the Pfizer-BioNTech and the Moderna COVID-19 vaccines. Because there is an urgent need for COVID-19 vaccines and the FDA’s vaccine approval process can take months to years, the FDA first gives emergency use authorization to COVID-19 vaccines based on less data than is normally required. However, data must show that the vaccines are safe and effective before the FDA can give emergency use authorization or approval. Vaccines have gone through — and continue to go through — extensive safety monitoring. From December 2020 to December 2025, billions of COVID-19 vaccines are given. Researchers at Mayo Clinic and other medical centers continue to study more about COVID-19 vaccines. ![ A young child wearing a mask gets a COVID-19 vaccine from a health care professional wearing a mask and face shield.](https://assets.mayoclinic.org/content/dam/media/global/images/2025/history-disease-outbreaks-vaccine-timeline/child-covid-vax-2208x1472-Getty-1306490855.jpg) COVID-19 vaccine A child wearing a mask gets a COVID-19 vaccine. ## 2021 The FDA gives emergency use authorization to the Janssen/Johnson & Johnson COVID-19 vaccine. The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 16 and older. The FDA authorizes the Pfizer-BioNTech vaccine for [children](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/covid-19-vaccines-for-kids/art-20513332) ages 5 through 15. Researchers continue to study and develop several other COVID-19 vaccines. Many COVID-19 vaccines are in clinical trials. ## 2022 The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 6 months to 4 years and the Moderna vaccine for children ages 6 months to 17 years. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized for people age 12 and older. ## 2023 The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Pfizer-BioNTech vaccine for people age 6 months to 11 years. The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Moderna vaccine for children 6 months to 11 years. ## 2024 Certain strains of the COVID-19 virus are targeted in the 2024-2025 COVID-19 vaccines based on the virus strains that are spreading. These include the Pfizer- BioNTech, Moderna and Novavax COVID-19 2024-2025 formula vaccines. The Novavax COVID-19 vaccine, adjuvanted, 2024-2025 formula is authorized for people age 12 and older. ## 2025 The 2025-2026 COVID-19 vaccines available in the United States include Moderna, Pfizer-BioNTech and Novavax. The vaccines are all approved for people age 65 and older. Each vaccine also is approved for younger people with a health condition that raises the risk of serious COVID-19 illness. ## Learn more: - COVID-19 vaccines - [COVID-19 vaccines: Get the facts](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-vaccine/art-20484859) - [Comparing the differences between COVID-19 vaccines](https://www.mayoclinic.org/diseases-conditions/comparing-vaccines) - [Mayo Clinic expert discusses updated COVID-19 vaccines](https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-expert-discusses-updated-covid-19-vaccines/) - [mRNA vaccines and immunity (video)](https://www.mayoclinic.org/mrna-vaccines-immunity/vid-20507649) - [Different types of COVID-19 vaccines: How they work](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/different-types-of-covid-19-vaccines/art-20506465) - [Mayo Clinic expert discusses updated COVID-19 vaccines](https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-expert-discusses-updated-covid-19-vaccines/) - [Vector and Viral Engineering Lab](http://www.mayo.edu/research/labs/vector-vaccine-engineering) - COVID-19 vaccines and kids - [COVID-19 vaccines for kids: What you need to know](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/covid-19-vaccines-for-kids/art-20513332) - [Mayo Clinic Minute: 3 misconceptions about COVID-19 and flu vaccines](https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-minute-3-misconceptions-about-covid-19-and-the-flu-vaccines/) - COVID-19 treatment - [COVID-19 drugs: Are there any that work?](https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/coronavirus-drugs/faq-20485627) - [Treating COVID-19 at home: Care tips for you and others](http://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/treating-covid-19-at-home/art-20483273) - COVID-19 tests - [COVID-19 diagnostic testing](https://www.mayoclinic.org/tests-procedures/covid-19-diagnostic-test/about/pac-20488900) - [COVID-19 antibody testing](https://www.mayoclinic.org/tests-procedures/covid-19-antibody-testing/about/pac-20489696) - [How testing has kept up with new COVID-19 variants](https://newsnetwork.mayoclinic.org/discussion/how-testing-has-kept-up-with-new-covid-19-variants/) History of infectious disease outbreaks and vaccines timeline. Learn about the history of major disease outbreaks, epidemics and pandemics, as well as the impact vaccines and research had on many infectious diseases. Find out more at [History of infectious disease outbreaks and vaccines timeline](https://www.mayoclinic.org/diseases-conditions/history-disease-outbreaks-vaccine-timeline). Show References 1. Plotkin SA, et al., eds. Plotkin's Vaccines. 7th ed. Elsevier; 2018. [https://www.clinicalkey.com](https://www.clinicalkey.com/). Accessed Oct. 8, 2021. 2. Blake JB. Benjamin Waterhouse and the introduction of vaccination. Reviews of Infectious Diseases. Oxford University Press. 1987;doi:10.1093/clinids/9.5.1044. 3. Desmond A, et al. On the shoulders of giants — From Jenner’s cowpox to mRNA Covid vaccines. The New England Journal of Medicine. 2021; doi:10.1056/NEJMp2034334. 4. Saleh A, et al. Vaccine development throughout history. Cureus. 2021; doi:10.7759/cureus.16635. 5. The history of vaccines. College of Physicians of Philadelphia. [https://www.historyofvaccines.org](https://www.historyofvaccines.org/). Accessed Oct. 7, 2021. 6. Stokes J, et al. Trivalent combined measles-mumps-rubella vaccine. JAMA. 1971;218:57. 7. Klein NP. Licensed pertussis vaccine in the United States: History and current state. 2014; doi:10.4161/hv.29576. 8. Influenza historic timeline. Centers for Disease Control and Prevention. <https://archive.cdc.gov/www_cdc_gov/flu/pandemic-resources/pandemic-timeline-1930-and-beyond.htm>. Accessed Nov. 14, 2024. 9. Poland GA, et al. Development of vaccines against Zika virus. The Lancet. Infectious Diseases. 2018; doi:10.1016/S1473-3099(18)30063-X. 10. Poland GA, et al. Zika vaccine development: Current status. Mayo Clinic Proceedings. 2019; doi:10.1016/j.mayocp.2019.05.016. 11. Li YD, et al. Coronavirus vaccine development: From SARS and MERS to COVID-19. Journal of Biomedical Science. 2020; doi:10.1186/s12929-020-00695-2. 12. Dolgin E. The tangled history of mRNA vaccines. Nature. 2021; doi:10.1038/d41586-021-02483-w. 13. Goodman RA, et al., eds. Vaccination mandates: The public health imperative and individual rights. In: Law in Public Health Practice. Oxford University Press; 2007. 14. Centers for Disease Control and Prevention. Current trends childhood immunization initiative, United States — 5-year follow up. MMWR Morbidity and Mortality Weekly Report. 1982; <http://www.cdc.gov/mmwr/preview/mmwrhtml/00001091.htm>. Accessed Oct. 7, 2021. 15. Vaccination. Office of Disease Prevention and Health Promotion. https:// odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/vaccination. Accessed Nov. 13, 2024. 16. The history of vaccines. History of the immunization schedule. College of Physicians of Philadelphia. https:// historyofvaccines.org/activities/history-immunization-schedule. Accessed Nov. 13, 2024. 17. NCIRD national surveillance materials and resources. Centers for Disease Control and Prevention. <https://www.cdc.gov/ncird-surveillance/resources/index.html>. Accessed Nov. 13, 2024. 18. Roush SW, et al. Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. JAMA. 2007; doi:10.1001/jama.298.18.2155. 19. Poland GA (expert opinion). Mayo Clinic. Sept. 17, 2021. 20. FDA approves and authorizes updated mRNA COVID-19 vaccines to better protect against currently circulating variants. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/fda-approves-and-authorizes-updated-mrna-covid-19-vaccines-better-protect-against-currently. Accessed Dec. 6, 2024. 21. 1918 pandemic influenza timeline. Centers for Disease Control and Prevention. https:// archive.cdc.gov/www\_cdc\_gov/flu/pandemic-resources/1918-commemoration/pandemic-timeline-1918.htm. Accessed Nov. 14, 2024. 22. Recommendations for COVID-19 vaccines in infants, children, and adolescents: Policy statement. Pediatrics. 2025;doi:10.1542/peds.2025-073924. 23. Medical review (expert opinion). Mayo Clinic. Sept. 25, 2025. 24. COVID-19 vaccines. U.S. Food and Drug Administration. <https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/covid-19-vaccines>. Accessed Dec. 2, 2024. 25. Poland GA, et al. The age-old struggle against the antivaccinationists. The New England Journal of Medicine. 2011; doi:10.1056/NEJMp1010594. 26. Clapesattle H. The Doctors Mayo. The University of Minnesota Press; 1941. 27. Saint Mary's isolation hospital during the influenza pandemic. Saint Marys Hospital Annals; 1918. 28. Harren R. Olmsted country in the grippe of Spanish influenza. The Scribe. History Center of Olmsted Country. 2018. 29. Strand PK. A Century of Caring: 1889-1989. Saint Marys Hospital; 1988. 30. Mayo Clinic: The battle plan for H1N1. Mayo Alumni Magazine; 2009. 31. First polio vaccine delivery. MayoVox. Mayo Clinic; 1955. 32. Rosenow EC. Prophylactic inoculation against respiratory infections during the present pandemic of influenza: Preliminary report. Mayo Clinic; 1918. 33. Rules concerning the report of contagious diseases. The Clinic Bulletin. 1919;1;1. 34. Maltezou HA, et al. Immunization of health-care providers: Necessity and public-health policies. Healthcare. 2016; doi:10.3390/healthcare4030047. 35. Voigt EA, et al. Defending against smallpox: A focus on vaccines. Expert Review of Vaccines. 2016; doi:10.1080/14760584.2016.1175305. 36. Wright GH, et al. Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: A randomized trial. Vaccine. 2014; doi:10.1016/j.vaccine.2013.10.039. 37. Spikevax. U.S. Food and Drug Administration. <https://www.fda.gov/vaccines-blood-biologics/spikevax>. Accessed Dec. 2, 2024. 38. Infectious Disease. Office of Disease Prevention and Health Promotion. https:// odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/infectious-disease. Accessed Nov. 13, 2024. 39. Coronavirus disease (COVID-19). World Health Organization. <https://www.who.int/news-room/fact-sheets/detail/coronavirus-disease-(covid-19)>. Accessed Nov. 27, 2024. 40. Spikevax (approval letter). Biologic License Application 125752. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/spikevax. Accessed Sept. 25, 2025. 41. Mnexspike (approval letter). Biologic License Application 125835 U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/mnexspike. Accessed Sept. 25, 2025. 42. Comirnaty (approval letter). Biologic License Application 125742. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/comirnaty. Accessed Sept. 25, 2025. 43. Nuvaxovid (approval letter). Biologic License Application 125817. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/vaccines/nuvaxovid. Accessed Sept. 25, 2025. 44. AskMayoExpert. COVID-19 vaccination. Mayo Clinic; 2025. ![](https://assets.mayoclinic.org/content/dam/mayoclinic/images/icons/person-physician.svg) ## National Doctors’ Day is March 30\! [Give Now\!](https://give.mayoclinic.org/campaign/769678/donate?utm_source=devappeal&utm_medium=devweb&utm_campaign=devdoctorsday&preset1=50&preset2=100&preset3=250&preset4=1000&amount=100&currency=USD&c_src=26R031WG1MWV90Z11B) Your gift to celebrate this day advances our doctors’ lifesaving work. 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Readable Markdown	2020COVID-19 and related vaccine development and research Find out more about the COVID-19 pandemic, COVID-19 tests, COVID-19 treatments, mRNA research and COVID-19 vaccines. ![Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19](https://assets.mayoclinic.org/content/dam/media/global/images/2025/history-disease-outbreaks-vaccine-timeline/coronavirus2-structure-2208x1472-1668678_3931480-001.jpg) The virus that causes COVID-19 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19 1984 Paul A. Krieg, Ph.D., Douglas A. Melton, Ph.D., Tom Maniatis, Ph.D., and Michael Green, Ph.D., and colleagues at Harvard University use a synthesized RNA enzyme to make biologically active messenger RNA (mRNA) in a lab. A similar process is still used today to make synthetic mRNA. Drs. Krieg and Melton use synthetic mRNA to study gene function and activity. Other researchers also study RNA. 1987 Robert W. Malone, M.D., M.S., mixes mRNA with fat droplets. He discovers that when human cells are added to this mixture, they absorb the mRNA and make proteins. Dr. Malone also finds that frog embryos absorb mRNA. These experiments are considered early steps in the eventual development of mRNA-based COVID-19 vaccines. 1990s Researchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice. 2000s Several researchers study mRNA treatments or vaccines. But since mRNA is easy to damage and expensive to produce, many researchers can’t get funding to pursue this work and so the research often wasn’t pursued. 2005 Katalin Kariko, Ph.D., and Drew Weissman, M.D., Ph.D., discover that modifying synthetic mRNA keeps the immune system from attacking the mRNA. This discovery moves mRNA vaccine research forward. 2010s Many researchers study mRNA treatments or vaccines. 2019 A new coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in China. The SARS-CoV-2 virus causes [coronavirus disease 2019 (COVID-19)](https://www.mayoclinic.org/diseases-conditions/coronavirus/symptoms-causes/syc-20479963). WHO will declare the COVID-19 outbreak a pandemic in 2020. WHO and CDC issue recommendations for preventing and treating COVID-19. By January 2021, COVID-19 will cause about 2.5 million deaths worldwide. 2020 Many COVID-19 vaccine clinical trials are in process. Researchers take what was previously learned from vaccine studies of SARS-CoV, MERS-CoV and other viruses to develop [vaccines](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-vaccine/art-20484859) that prevent COVID-19. Researchers also study [COVID-19 symptoms](https://www.mayoclinic.org/diseases-conditions/coronavirus/symptoms-causes/syc-20479963), [long-term effects](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-long-term-effects/art-20490351), [diagnostic tests](https://www.mayoclinic.org/tests-procedures/covid-19-diagnostic-test/about/pac-20488900), [antibody tests](https://www.mayoclinic.org/tests-procedures/covid-19-antibody-testing/about/pac-20489696), treatments and [drugs](https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/coronavirus-drugs/faq-20485627). Mayo Clinic researchers study and develop a COVID-19 diagnostic test, an antibody test, monoclonal antibody medications, [convalescent plasma therapy](http://www.mayoclinic.org/tests-procedures/convalescent-plasma-therapy/about/pac-20486440) and vaccines. ### COVID-19 vaccines In the U.S., the Food and Drug Administration (FDA) gives emergency use authorization to two mRNA [COVID-19 vaccines](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-vaccine/art-20484859), the Pfizer-BioNTech and the Moderna COVID-19 vaccines. Because there is an urgent need for COVID-19 vaccines and the FDA’s vaccine approval process can take months to years, the FDA first gives emergency use authorization to COVID-19 vaccines based on less data than is normally required. However, data must show that the vaccines are safe and effective before the FDA can give emergency use authorization or approval. Vaccines have gone through — and continue to go through — extensive safety monitoring. From December 2020 to December 2025, billions of COVID-19 vaccines are given. Researchers at Mayo Clinic and other medical centers continue to study more about COVID-19 vaccines. ![ A young child wearing a mask gets a COVID-19 vaccine from a health care professional wearing a mask and face shield.](https://assets.mayoclinic.org/content/dam/media/global/images/2025/history-disease-outbreaks-vaccine-timeline/child-covid-vax-2208x1472-Getty-1306490855.jpg) COVID-19 vaccine A child wearing a mask gets a COVID-19 vaccine. 2021 The FDA gives emergency use authorization to the Janssen/Johnson & Johnson COVID-19 vaccine. The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 16 and older. The FDA authorizes the Pfizer-BioNTech vaccine for [children](https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/covid-19-vaccines-for-kids/art-20513332) ages 5 through 15. Researchers continue to study and develop several other COVID-19 vaccines. Many COVID-19 vaccines are in clinical trials. 2022 The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older. The FDA authorizes the Pfizer-BioNTech vaccine for children ages 6 months to 4 years and the Moderna vaccine for children ages 6 months to 17 years. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized. The Novavax COVID-19 vaccine is authorized for people age 18 and older, and soon it is authorized for people age 12 and older. 2023 The FDA approves the Pfizer-BioNTech COVID-19 vaccine, now called Comirnaty, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Pfizer-BioNTech vaccine for people age 6 months to 11 years. The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 12 and older. The FDA authorizes the Moderna vaccine for children 6 months to 11 years. 2024 Certain strains of the COVID-19 virus are targeted in the 2024-2025 COVID-19 vaccines based on the virus strains that are spreading. These include the Pfizer- BioNTech, Moderna and Novavax COVID-19 2024-2025 formula vaccines. The Novavax COVID-19 vaccine, adjuvanted, 2024-2025 formula is authorized for people age 12 and older. 2025 The 2025-2026 COVID-19 vaccines available in the United States include Moderna, Pfizer-BioNTech and Novavax. The vaccines are all approved for people age 65 and older. Each vaccine also is approved for younger people with a health condition that raises the risk of serious COVID-19 illness. Learn more: 1. Plotkin SA, et al., eds. Plotkin's Vaccines. 7th ed. Elsevier; 2018. [https://www.clinicalkey.com](https://www.clinicalkey.com/). Accessed Oct. 8, 2021. 2. Blake JB. Benjamin Waterhouse and the introduction of vaccination. Reviews of Infectious Diseases. Oxford University Press. 1987;doi:10.1093/clinids/9.5.1044. 3. Desmond A, et al. On the shoulders of giants — From Jenner’s cowpox to mRNA Covid vaccines. The New England Journal of Medicine. 2021; doi:10.1056/NEJMp2034334. 4. Saleh A, et al. Vaccine development throughout history. Cureus. 2021; doi:10.7759/cureus.16635. 5. The history of vaccines. College of Physicians of Philadelphia. [https://www.historyofvaccines.org](https://www.historyofvaccines.org/). Accessed Oct. 7, 2021. 6. Stokes J, et al. Trivalent combined measles-mumps-rubella vaccine. JAMA. 1971;218:57. 7. Klein NP. Licensed pertussis vaccine in the United States: History and current state. 2014; doi:10.4161/hv.29576. 8. Influenza historic timeline. Centers for Disease Control and Prevention. <https://archive.cdc.gov/www_cdc_gov/flu/pandemic-resources/pandemic-timeline-1930-and-beyond.htm>. Accessed Nov. 14, 2024. 9. Poland GA, et al. Development of vaccines against Zika virus. The Lancet. Infectious Diseases. 2018; doi:10.1016/S1473-3099(18)30063-X. 10. Poland GA, et al. Zika vaccine development: Current status. Mayo Clinic Proceedings. 2019; doi:10.1016/j.mayocp.2019.05.016. 11. Li YD, et al. Coronavirus vaccine development: From SARS and MERS to COVID-19. Journal of Biomedical Science. 2020; doi:10.1186/s12929-020-00695-2. 12. Dolgin E. The tangled history of mRNA vaccines. Nature. 2021; doi:10.1038/d41586-021-02483-w. 13. Goodman RA, et al., eds. Vaccination mandates: The public health imperative and individual rights. In: Law in Public Health Practice. Oxford University Press; 2007. 14. Centers for Disease Control and Prevention. Current trends childhood immunization initiative, United States — 5-year follow up. MMWR Morbidity and Mortality Weekly Report. 1982; <http://www.cdc.gov/mmwr/preview/mmwrhtml/00001091.htm>. Accessed Oct. 7, 2021. 15. Vaccination. Office of Disease Prevention and Health Promotion. https:// odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/vaccination. Accessed Nov. 13, 2024. 16. The history of vaccines. History of the immunization schedule. College of Physicians of Philadelphia. https:// historyofvaccines.org/activities/history-immunization-schedule. Accessed Nov. 13, 2024. 17. NCIRD national surveillance materials and resources. Centers for Disease Control and Prevention. <https://www.cdc.gov/ncird-surveillance/resources/index.html>. Accessed Nov. 13, 2024. 18. Roush SW, et al. Historical comparisons of morbidity and mortality for vaccine-preventable disease in the United States. JAMA. 2007; doi:10.1001/jama.298.18.2155. 19. Poland GA (expert opinion). Mayo Clinic. Sept. 17, 2021. 20. FDA approves and authorizes updated mRNA COVID-19 vaccines to better protect against currently circulating variants. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/fda-approves-and-authorizes-updated-mrna-covid-19-vaccines-better-protect-against-currently. Accessed Dec. 6, 2024. 21. 1918 pandemic influenza timeline. Centers for Disease Control and Prevention. https:// archive.cdc.gov/www\_cdc\_gov/flu/pandemic-resources/1918-commemoration/pandemic-timeline-1918.htm. Accessed Nov. 14, 2024. 22. Recommendations for COVID-19 vaccines in infants, children, and adolescents: Policy statement. Pediatrics. 2025;doi:10.1542/peds.2025-073924. 23. Medical review (expert opinion). Mayo Clinic. Sept. 25, 2025. 24. COVID-19 vaccines. U.S. Food and Drug Administration. <https://www.fda.gov/emergency-preparedness-and-response/coronavirus-disease-2019-covid-19/covid-19-vaccines>. Accessed Dec. 2, 2024. 25. Poland GA, et al. The age-old struggle against the antivaccinationists. The New England Journal of Medicine. 2011; doi:10.1056/NEJMp1010594. 26. Clapesattle H. The Doctors Mayo. The University of Minnesota Press; 1941. 27. Saint Mary's isolation hospital during the influenza pandemic. Saint Marys Hospital Annals; 1918. 28. Harren R. Olmsted country in the grippe of Spanish influenza. The Scribe. History Center of Olmsted Country. 2018. 29. Strand PK. A Century of Caring: 1889-1989. Saint Marys Hospital; 1988. 30. Mayo Clinic: The battle plan for H1N1. Mayo Alumni Magazine; 2009. 31. First polio vaccine delivery. MayoVox. Mayo Clinic; 1955. 32. Rosenow EC. Prophylactic inoculation against respiratory infections during the present pandemic of influenza: Preliminary report. Mayo Clinic; 1918. 33. Rules concerning the report of contagious diseases. The Clinic Bulletin. 1919;1;1. 34. Maltezou HA, et al. Immunization of health-care providers: Necessity and public-health policies. Healthcare. 2016; doi:10.3390/healthcare4030047. 35. Voigt EA, et al. Defending against smallpox: A focus on vaccines. Expert Review of Vaccines. 2016; doi:10.1080/14760584.2016.1175305. 36. Wright GH, et al. Effect of reduced dose schedules and intramuscular injection of anthrax vaccine adsorbed on immunological response and safety profile: A randomized trial. Vaccine. 2014; doi:10.1016/j.vaccine.2013.10.039. 37. Spikevax. U.S. Food and Drug Administration. <https://www.fda.gov/vaccines-blood-biologics/spikevax>. Accessed Dec. 2, 2024. 38. Infectious Disease. Office of Disease Prevention and Health Promotion. https:// odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/infectious-disease. Accessed Nov. 13, 2024. 39. Coronavirus disease (COVID-19). World Health Organization. <https://www.who.int/news-room/fact-sheets/detail/coronavirus-disease-(covid-19)>. Accessed Nov. 27, 2024. 40. Spikevax (approval letter). Biologic License Application 125752. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/spikevax. Accessed Sept. 25, 2025. 41. Mnexspike (approval letter). Biologic License Application 125835 U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/mnexspike. Accessed Sept. 25, 2025. 42. Comirnaty (approval letter). Biologic License Application 125742. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/comirnaty. Accessed Sept. 25, 2025. 43. Nuvaxovid (approval letter). Biologic License Application 125817. U.S. Food and Drug Administration. https://www.fda.gov/vaccines-blood-biologics/vaccines/nuvaxovid. Accessed Sept. 25, 2025. 44. AskMayoExpert. COVID-19 vaccination. Mayo Clinic; 2025.
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