Facts About COVID-19 Vaccines From the FDA

Learn about the evidence supporting FDA-approval of Comirnaty and FDA emergency use authorization of COVID-19 vaccines

The U.S. Food and Drug Administration approved Comirnaty for the prevention of COVID-19 caused by SARS-CoV-2 in individuals 16 years of age and older. The vaccine has the same formulation as the Pfizer-BioNTech COVID-19 Vaccine that continues to be available under emergency use authorization (EUA), including for individuals 12 through 15 years of age, for the administration of a third dose in certain immunocompromised individuals, and for a single booster dose in certain populations.

Three COVID-19 vaccines are authorized for emergency use. The vaccines are:

Who authorizes COVID-19 vaccines for emergency use?

The FDA is the regulatory authority with oversight of the safety, effectiveness and quality of vaccines that are used in the U.S., including COVID-19 vaccines. Career scientists and doctors at the FDA determine whether to approve or authorize COVID-19 vaccines after they thoroughly analyze and evaluate the data submitted by the manufacturer related to safety, effectiveness and manufacturing quality.

During a public health emergency like the current COVID-19 pandemic, the FDA may issue an EUA when the agency’s scientific experts have determined, among other things, that the known and potential benefits of the vaccine outweigh its known and potential risks.

For Comirnaty, the company submitted a Biologics License application (BLA) to FDA which built on the extensive data and information previously submitted that supported the EUA. This included preclinical and clinical data and information, as well as details of the manufacturing process, vaccine testing results to ensure vaccine quality, and inspections at the sites at which the vaccine is made.

FDA employees are also fathers, mothers, daughters, sons, sisters, brothers and more. They and their families are directly impacted by the work they do.

Why should I get a COVID-19 vaccine?

When you get a COVID-19 vaccine, you are choosing to protect yourself and make a difference for your children, parents, grandparents, and other loved ones. For a community to be fully protected, most community members need to get the vaccine. Getting vaccinated to prevent COVID-19 will help protect you from COVID-19, and it may also protect the people around you.

Do COVID-19 vaccines work?

Yes. All FDA-approved and FDA-authorized COVID-19 vaccines prevent COVID-19 and serious health outcomes that COVID-19 can cause, including hospitalization and death. The FDA thoroughly evaluated and analyzed safety and effectiveness data for Comirnaty, the approved COVID-19 vaccine and those vaccines authorized for emergency use.

In evaluating requests for emergency use authorization for COVID-19 vaccines, the FDA determined that the available data provided clear evidence that the known and potential benefits outweigh the known and potential risks of each vaccine.

In evaluating the data and information included in the BLA for Comirnaty, the FDA determined that the vaccine is safe and effective and meets our rigorous standards for approval.

Do COVID-19 vaccines work against variants of the virus that causes COVID-19?

The available information suggests that the approved vaccine and the authorized vaccines protect the American public against COVID-19 caused by currently circulating strains of the virus that causes COVID-19.

Some variants are more contagious and spread more easily from person-to-person than the original virus that causes COVID-19. To help slow the spread of COVID-19, get a COVID-19 vaccine when it is available to you.

What safety information is available about COVID-19 vaccines?

The FDA evaluated data from clinical studies that included tens of thousands of people for Comirnaty, the FDA-approved COVID-19 vaccine, and for each of the COVID-19 vaccines authorized for emergency use.

Authorized COVID-19 Vaccines

The FDA has authorized three vaccines for emergency use because the data from clinical studies clearly showed that the known and potential benefits of the FDA-authorized COVID-19 vaccines outweighed the known and potential risks.

Approved COVID-19 Vaccine

The data to support the decision to approve Comirnaty builds on extensive data and information that supported the Pfizer-BioNTech COVID-19 Vaccine EUA , including information about the vaccine’s safety and effectiveness. The safety of Comirnaty was evaluated in individuals 16 years of age and older, approximately 22,000 of whom received the vaccine and 22,000 of whom received placebo. More than half of the clinical trial participants were followed for safety follow-up for at least four months after the second dose. After issuance of the EUA, clinical trial participants were unblinded in a phased manner over a period of months to offer placebo recipients the Pfizer-BioNTech COVID-19 Vaccine. Overall, in blinded and unblinded follow-up, approximately 12,000 vaccine recipients have been followed for at least 6 months.

Allergic Reactions

Allergic reactions, including cases of anaphylaxis have happened after some people received a COVID-19 vaccine. Anaphylaxis is a severe, life-threatening allergic reaction that happens within seconds or minutes of exposure to an allergen. Because of this remote chance of severe allergic reaction or anaphylaxis, health care providers may ask you to stay at the place where you received your COVID-19 vaccine for monitoring for 15 to 30 minutes.

Myocarditis and Pericarditis Following Vaccination with Comirnaty, Moderna and Pfizer-BioNTech COVID-19 Vaccines

Post-authorization safety surveillance data pertaining to myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the tissue surrounding the heart) demonstrate increased risks of myocarditis and pericarditis, particularly within 7 days following the second dose of the Comirnaty, Moderna, and Pfizer-BioNTech COVID-19 vaccines. For each of these vaccines, the risk is higher in males under 40 years of age than in females or older males.

The Prescribing Information for Comirnaty and the Fact Sheets for Healthcare Providers Administering Vaccine (Vaccination Providers) for the Moderna and Pfizer-BioNTech COVID-19 vaccines include a warning about to the risk of myocarditis and pericarditis, and the Fact Sheet for Recipients and Caregivers includes information about myocarditis and pericarditis. The Fact Sheets for Recipients and Caregivers note that vaccine recipients should seek medical attention right away if they experience any of the following symptoms after vaccination:
•   Chest pain
•   Shortness of breath
•   Feelings of having a fast-beating, fluttering, or pounding heart

Based on available information of the confirmed reported cases of myocarditis or pericarditis, most affected individuals were hospitalized and most responded well to treatment and rest, and their symptoms went away quickly.

FDA and CDC are monitoring the reports, collecting more information, and will follow-up to assess longer-term outcomes over several months.

Guillain Barré Syndrome Following Vaccination with Janssen COVID-19 Vaccine

Guillain Barré syndrome (a neurological disorder in which the body’s immune system damages nerve cells, causing muscle weakness and sometimes paralysis) has occurred in some people who have received the Janssen COVID-19 Vaccine. In most of these people, symptoms began within 42 days following receipt of the Janssen COVID-19 Vaccine. The chance of having this occur is very low. The Fact Sheet for Healthcare Providers Administering Vaccine (Vaccination Providers) includes a warning about the suggested increased risk of Guillain Barré Syndrome (GBS) and the Fact Sheet for Recipients and Caregivers includes information about GBS. The Fact Sheet for Recipients and Caregivers notes that vaccine recipients should seek medical attention right away if they experience any of the following symptoms after receiving the Janssen COVID-19 Vaccine:

Weakness or tingling sensations, especially in the legs or arms, that’s worsening and spreading to other
parts of the body
Difficulty walking
Difficulty with facial movements, including speaking, chewing, or swallowing
Double vision or inability to move eyes
Difficulty with bladder control or bowel function

Blood Clots in Combination with Low Blood Platelets Following Vaccination with Janssen COVID-19 Vaccine

As a result of ongoing safety monitoring, on April 13, 2021, the FDA and CDC recommended a temporary pause in the use of Janssen COVID-19 Vaccine, due to reports of a serious and rare type of blood clot in combination with low blood platelets (blood cells that help your body stop bleeding). This serious condition is called thrombosis with thrombocytopenia syndrome (TTS).