Diversity in Vaccine Studies

Updated May 16, 2022

How vaccines are tested

All vaccines, including the new COVID-19 vaccines, go through a series of studies and checks (called clinical trials) to make sure they are safe, and that they work, before they are given to the public. Vaccines continue to be monitored for safety even after they are approved.

It is important that the clinical trials include a diverse group of people. Researchers need enough information to be sure the vaccine is safe and works for all groups. It’s especially important for COVID-19 because communities of color have been severely affected by the disease and vaccination could help communities move forward.

Are they tested in people like me?

You might feel concerned about whether COVID-19 vaccines were tested on people with your same racial or ethnic background or your same health concerns.

If you are a person of color, you might feel especially worried about taking these vaccines. Medical racism in the past and present is real.

You may be wondering if you can trust these vaccines and the systems that developed them that have broken trust with your community before.

Rebuilding Trust

Two vaccines have received Emergency Use Authorization (EUA) by the Food and Drug Administration (FDA) for use here in the U.S.-- Moderna and Johnson & Johnson; Pfizer/BioNTech received full FDA approval on August 23, 2021. More than a hundred additional vaccines are in different stages of development all over the world. More will likely be authorized in the future.

For COVID-19 vaccines, researchers worked hard to rebuild trust with communities and recruit diverse volunteers for their studies. They included diversity in race, ethnicity and age, as well as in health conditions. The studies ended up being more diverse than other vaccine studies have been in the past. The mix of people participating in the studies looks more like the overall population of the U.S.

Pfizer vaccine studies

Total people in Phase 3 studies - about 45,000 people
About 30% of U.S. participants identify as people of color (44% worldwide).
About 46% had at least one health condition that increases the risk of severe COVID-19 disease, including: obesity, diabetes, and ongoing lung disease.
Study participants were aged 12 to 56+.
Vaccine efficacy 95%: Efficacy is a measure of how well the vaccine protects people compared to those who don’t get the vaccine. The higher the number the better.
Read more about demographic data from Pfizer

Moderna vaccine studies

Total people in Phase 3 studies - about 30,000 people
37% of U.S. participants identify as people of color.
About 22% of participants had at least one health condition that increases the risk of severe COVID-19 disease, including diabetes, obesity, heart disease, ongoing lung disease, and liver disease.
Study participants were aged 18 to 65+.
Vaccine efficacy 94%: Efficacy is a measure of how well the vaccine protects people compared to those who don’t get the vaccine. The higher the number the better.
Read more about demographic data from Moderna

Johnson & Johnson (Janssen) vaccine studies

Total people in Phase 3 studies - almost 44,000 people:

35% of people in the U.S. studies identified as people of color. (76% worldwide)
About 41% of participants had at least one health condition that increases the risk of severe COVID-19 disease, including obesity, type 2 diabetes and hypertension
Study participants were aged 18 to 65+.

Information about Johnson & Johnson COVID Vaccine (CDC)

Scientists are still learning more

Getting fully vaccinated and a booster dose is our best defense against COVID-19.

Like with all medicines, medical experts continue to keep track of any possible safety concerns with the vaccines. They do this through a safety reporting system called V-Safe. This way they are able to find and address even the most rare concerns as vaccines are given to millions of people.

After looking more closely at the vaccines, national experts have decided that mRNA vaccines are preferred over Johnson & Johnson. People can still get the single dose J&J if they prefer, if it is the only available vaccine, or if they otherwise cannot receive an mRNA vaccine.

Vaccines will help protect you and prevent the spread of COVID-19. We recommend getting a COVID-19 vaccine as soon as you can.