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

The virus that causes COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19


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.


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.


Researchers test mRNA as a treatment in rats and as an influenza and cancer vaccine in mice.


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.


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.


Many researchers study mRNA treatments or vaccines.


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.


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

The 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 gave emergency use authorization to COVID-19 vaccines based on less data than is normally required. The 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. Millions of COVID-19 vaccines have been given since December 2020.

Researchers at Mayo Clinic and other medical centers continue to study more vaccines that prevent COVID-19.

A young girl wearing a mask gets a COVID-19 vaccine from a health care professional wearing a mask and face shield.

COVID-19 vaccine

A child wearing a mask gets a COVID-19 vaccine.


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 also 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.


The FDA approves the Moderna COVID-19 vaccine, now called Spikevax, to prevent COVID-19 in people age 18 and older.

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