Which COVID-19 vaccine is the best?

Ohio State nurse preparing to administer COVID-19 vaccine

On Aug. 23, 2021, the U.S. Food and Drug Administration approved the Pfizer COVID-19 vaccine for the prevention of COVID-19 disease in people 16 and older. As what we know about COVID-19 evolves, so could the information contained in this story. Find our most recent COVID-19 blog posts here.

You might have already decided that you prefer one COVID-19 vaccine over another based on the characteristics of each of the options.

But the question of which vaccine is “best” doesn’t have a straightforward answer. Considering the data we have available now as well as available vaccine supply, the vaccine that’s best for you is likely the vaccine that’s available to you.

The data right now suggests that both the Pfizer vaccine, which was formally approved by the FDA on Aug. 23, 2021, and the Moderna COVID-19 vaccine, which is authorized for emergency use, are very effective at preventing COVID-19 illness. The Johnson & Johnson vaccine is similarly effective in preventing severe COVID-19, and hospitalization and death from the virus.

The most important thing is just to get a COVID-19 vaccine, period.

COVID-19 vaccine images

Key differences in the COVID-19 vaccines, and what matters

Because of differences in the ways these vaccines were tested, it can be hard to compare them apples-to-apples. But here’s what we know:


Clinical trial data shows that the Pfizer and Moderna vaccines are 95% and 94.1% effective, respectively, at preventing COVID-19 illness. This is extraordinary for a virus vaccine — the annual flu vaccine, for example, is sometimes in the 50%-60% range of effectiveness at best, but is still so helpful at preventing illness that it’s recommended every year.

In clinical trials, the Johnson & Johnson COVID-19 vaccine showed 85% effectiveness in preventing severe COVID-19 and 100% effectiveness in preventing hospitalizations and death at 28 days after the injection. Get details on how the vaccines work.

Number of shots and intervals between doses

  • Pfizer requires a second dose 21 days after the first dose.
  • Moderna requires a second dose 28 days after the first dose.
  • Johnson & Johnson’s COVID-19 vaccine is designed to be delivered in one dose.

Side effects

All three of these COVID-19 vaccines include commonly reported side effects of pain/soreness at the injection site, headache, fatigue, muscle aches and nausea, which usually fully subsided within one to two days after vaccination.

The Moderna and Pfizer vaccines include some additional commonly reported side effects, such as chills, fever, joint pain and swollen lymph nodes. These side effects were more often reported after the second dose, though they are possible after either dose.

Since the Johnson & Johnson vaccine doesn’t require a second dose, there’s no increased risk of common side effects with a second dose.

 Patient being vaccinated for COVID-19

The bottom line with COVID-19 vaccines

We’re trying to prevent:

  • COVID-19 infection
  • COVID-19 transmission
  • Severe COVID-19 cases that would require hospitalization or cause either long-term effects or death

Every vaccine available right now is much more effective than no vaccine, and they all significantly reduce the likelihood of severe illness and death. This means that even on the chance that someone gets infected after receiving a COVID-19 vaccine, they’re less likely to spread it to others and less likely to end up in a hospital’s intensive care unit.

If we can get widespread immunization, we can decrease the community viral load (the amount of virus that’s circulating), and the more people that are vaccinated, the better the vaccine works in a population.

Getting as much of our population as possible immunized with any FDA-approved COVID-19 vaccine will help us reduce the threat of disease, control the pandemic and move forward with our lives.

Andrew Thomas is chief clinical officer of The Ohio State University Wexner Medical Center and senior associate vice president for Health Sciences at The Ohio State University.