COMIRNATY®

Why is it important to stay up to date on COVID-19 vaccinations, in accordance with CDC recommendations?

The protection you get against COVID-19 from previous vaccination decreases as time goes on, and as the virus that causes COVID-19 evolves. This can leave you at risk for COVID-19. That’s why getting an updated vaccine is one of the best ways to help protect yourself, and for your loved ones to protect themselves. Learn more about how our vaccine is given in our Dosing Guide.

What is the difference between an updated COVID-19 vaccine and a COVID-19 booster?

An updated vaccine is different than a booster shot. An updated vaccine contains an “updated” formula that is anticipated to help protect against the currently circulating strain(s) of the virus that causes COVID-19. Updated COVID-19 vaccines are made using a similar process as previous vaccine formulas.

A booster shot is an additional dose of the vaccine you previously received. It is given in order to help “boost” your immune system. Think of it this way: An updated vaccine helps provide immunity against new variants, while a booster helps restore immunity against previous variants.

The 2023-2024 formula COVID-19 vaccines are called “updated” vaccines by the FDA, not “boosters” like previous shots, because they build new immune response to variants that are currently circulating, instead of restoring immunity gained from a previous shot.

Some people may be eligible for additional doses of a 2023-2024 formula COVID-19 vaccine, which would function like a booster.

Were there clinical trials done for COMIRNATY?

The safety and efficacy of COMIRNATY were evaluated in a pivotal trial of approximately 46,000 people 12 years and older—one of the largest vaccine clinical trials Pfizer has ever conducted.

Yes, multiple clinical trials contributed to testing COMIRNATY. People in these clinical trials received a 2-dose series, 3 weeks apart (referred to as a primary series), and additional doses referred to as booster doses. Click here for more trial details.

The pivotal clinical trial (called Study 2) tested the safety of the original formula of COMIRNATY and how well it worked to help protect against COVID-19 and severe disease.

Additional clinical trials assessed the safety and effectiveness of updated versions of the vaccine that were adapted from the original formula to help protect against different strains of the COVID-19 virus. These studies are relevant to the 2023-2024 formula of COMIRNATY because the vaccines are made using the same process, with the difference only in the strain of COVID-19 targeted.

Previous formulas of our COVID-19 vaccines are no longer available for use in the US.

What is known about the safety of COMIRNATY?

COMIRNATY has been tested in multiple clinical trials with a demonstrated safety profile. Serious risks can include severe allergic reactions, myocarditis (inflammation of the heart muscle), or pericarditis (inflammation of the lining outside the heart). Some people may faint after vaccination and people with weakened immune systems may have a reduced immune response.

Common side effects in people 12 years of age and older include pain, swelling or redness where the shot is given, tiredness (fatigue), headache, chills, muscle and/or joint pain, and fever. Learn more about safety.

These may not be all the possible side effects of COMIRNATY. Ask your healthcare provider about any side effects that concern you.

The CDC, FDA, and other federal agencies continue to rigorously monitor the safety of COVID-19 vaccines, including the 2023-2024 formula of COMIRNATY, and share information with the public as it becomes available. Learn more from the CDC.

What are the benefits of COMIRNATY?

The FDA has approved COMIRNATY to help provide protection against COVID-19. The duration of protection is currently unknown. Learn more about the safety of COMIRNATY.