More than 240 million people in the United States, including 96% of medical doctors, have now received one dose of a COVID-19 vaccine. These vaccines have been through the most intensive safety monitoring in U.S. history.
Vaccines are approved and authorized by the U.S. Food and Drug Administration (FDA). The FDA sets strict standards for clinical trials and carefully reviews scientific data from vaccine developers. Once vaccines are made available to the public, the FDA continues to monitor them very closely.
Researchers began developing vaccines for COVID-19 in January 2020, based on decades of work on immune responses and vaccine technology. Thousands of volunteers took part in the clinical trials that started that spring to ensure the vaccines are safe and effective.
Based on the results, the FDA authorized multiple vaccines for public use. In August 2021, the Pfizer vaccine (Comirnaty) was approved by the FDA.
Doctors and medical experts with many years of experience regulating vaccines looked at information about the safety, effectiveness, and quality of the vaccines before making their decision.
- Comirnaty and Pfizer-BioNTech COVID-19 Vaccine Frequently Asked Questions (FDA)
The Pfizer-BioNTech vaccine has full FDA approval for people ages 16 and up. Within the U.S., the “Pfizer-BioNTech” and “Comirnaty” COVID-19 vaccines are identical. Companies can use brand names such as “Comirnaty” once a vaccine has received FDA approval.
The Pfizer vaccine is available to children from 5 to 15 under emergency use authorization. The Moderna and J&J vaccines are still available under emergency use authorization as the FDA continues to review all available data.
All three vaccines are effective at preventing serious illness, hospitalization, and death.
- How the FDA evaluated safety data (FDA)
The science behind the breakthrough had a head start. Researchers had already made progress developing vaccines for other types of coronaviruses. They applied lessons learned after the 2003 SARS epidemic and the 2012 MERS outbreak. They also learned a lot from creating a vaccine for Ebola, which isn’t a coronavirus but has taught us more about viruses.
The rapid spread of COVID-19 made developing these vaccines an international priority. It unlocked billions of dollars in funding to ensure safety while moving with urgency to save lives.
Many researchers and medical experts have come together to develop the vaccine while still meeting the FDA’s rigorous requirements for safety and effectiveness. While regulators have streamlined some steps in the authorization process, the vaccines still needed to meet the FDA’s high standards for safety, effectiveness, and manufacturing quality.
After a vaccine is authorized by the FDA and made available to the public, experts continue to keep track of data. They are monitoring for ongoing safety and to help us learn more about questions like whether vaccinated people can still get infected without having symptoms
- Vaccine testing and approval process (CDC)
Every vaccine must go through rigorous testing and inspection to ensure it’s safe.
COVID-19 vaccines followed a 3-phase process. Several important stages were required before FDA authorization and approval.
Phase 1: The vaccine is tested in a small number of generally healthy adults, usually between 20 and 80 people. It’s evaluated for safety, dosage, and any side effects. Experts also look at what type of immune response is created.
Phase 2: If there are no safety concerns from Phase I studies, the vaccine is given in various dosages to hundreds of adults who come from different backgrounds and may have varied health issues. These studies provide more safety information on common short-term side effects and risks. They look at the relationship between the dose given and the immune response, and may provide initial insight into how effective the vaccine is.
Phase 3: Experts broaden the study to include thousands of adults from a variety of ages and backgrounds. They see how many people who got the vaccine were protected from the disease, compared to those who received a placebo. Another major goal of phase 3 trials is assessing safety, both short-term (e.g., fever, tenderness, muscle aches) and long-term (e.g., autoimmune conditions or enhanced disease following injection).
After a vaccine is authorized by the FDA and made available to the public, FDA continues to monitor its safety very closely. FDA also continues to oversee the production of the vaccine, including periodic safety checks on facilities where it is made.
- About COVID-19 vaccine trials (Duke Health)
Researchers made sure that the trials included adults from many types of backgrounds, races, ethnicities, and geographies. They worked closely with faith leaders, community groups, and health clinics across the United States to reach volunteers from different walks of life.
Medical experts want to make sure the vaccines work safely and effectively for as many people as possible. People may respond differently to vaccines based on factors like age, gender, and health conditions — so it is important to have a diverse group of participants in clinical trials.
COVID-19 has hit hard in the Black and Hispanic communities. Historically, these populations haven’t always been included in clinical research. With COVID-19 vaccines researchers made sure volunteers included people of color, as well as people over the age of 65 who are at higher risk of complications from the virus.
- Safety of COVID-19 Vaccines (CDC)
It is extremely unlikely you will suffer serious side effects that could cause a long-term health problem after getting a COVID-19 vaccine.
Long-term side effects following any vaccination are extremely rare. In the past vaccine monitoring has shown that if side effects are going to happen, they tend to happen within six weeks of receiving a vaccine dose.
For this reason, the FDA required each of the authorized COVID-19 vaccines to be studied for at least eight weeks after the final dose. Millions of people have received COVID-19 vaccines, and no long-term side effects have been found.
The CDC continues to closely monitor COVID-19 vaccines for any safety issues, including problems with manufacturing, a specific lot, or the vaccine itself. If public health experts find any potential safety concerns, FDA and the vaccine manufacturer will work towards a solution.
- COVID-19 Vaccines While Pregnant or Breastfeeding (CDC)
After extensive clinical trials and close examination, doctors have not found any evidence that COVID-19 vaccines cause fertility problems.
If you are trying to become pregnant now or want to get pregnant in the future, you may safely receive a COVID-19 vaccine.
Looking for a vaccine? Visit the Vaccine Finder to get up-to-date information on locations near you.