Pfizer-BioNTech COVID-19 Vaccine Overview and Safety
Manufacturer: Pfizer, Inc., and BioNTech
Type of Vaccine: mRNA
Number of Shots: 2 shots, 21 days apart
How Given: Shot in the muscle of the upper arm
Does NOT Contain: Eggs, preservatives, latex
Full List of Ingredients [PDF – 6 pages]external icon
- The Pfizer-BioNTech vaccine is recommended for people aged 16 years and older.
- Learn more about how CDC is making COVID-19 vaccine recommendations and CDC’s vaccine rollout recommendations.
- If you have had a severe allergic reaction (anaphylaxis) or an immediate allergic reaction, even if it was not severe:
- to any ingredient in an mRNA COVID-19 vaccine (such as polyethylene glycol), you should not get an mRNA COVID-19 vaccine.*
- or after getting the first dose of the vaccine, you should not get a second dose of either of the mRNA COVID-19 vaccines.
- An allergic reaction is considered severe when a person needs to be treated with epinephrine or EpiPen© or if they must go to the hospital. Learn about common side effects of COVID-19 vaccines and when to call a doctor.
- An immediate allergic reaction means a reaction within 4 hours of getting vaccinated, including symptoms such as hives, swelling, or wheezing (respiratory distress).
If you aren’t able to get an mRNA COVID-19 vaccine, you may still be able to get a different type of COVID-19 vaccine. Learn more information for people with allergies.
Possible Side Effects
In the arm where you got the shot:
Throughout the rest of your body:
- Muscle pain
These side effects usually start within a day or two of getting the vaccine. Side effects might affect your ability to do daily activities, but they should go away in a few days.
You should get the first COVID-19 vaccine that is available to you. Do not wait for a specific brand. All currently authorized and recommended COVID-19 vaccines are safe and effective, and CDC does not recommend one vaccine over another.
Safety Data Summary
- In clinical trials, reactogenicity symptoms (side effects that happen within 7 days of getting vaccinated) were common but were mostly mild to moderate.
- Side effects (such as fever, chills, tiredness, and headache) throughout the body were more common after the second dose of the vaccine.
- Most side effects were mild to moderate. However, a small number of people had severe side effects—defined as side effects affecting a person’s ability to do daily activities.
- Although few people in the clinical trials went to the hospital or died, data suggest that people who got the Pfizer-BioNTech vaccine were less likely to have these more serious outcomes compared to people who got the saline placebo.
- CDC will continue to provide updates as we learn more about the safety of the Pfizer-BioNTech vaccine in real-world conditions.
Learn more about vaccine safety monitoring after a vaccine is authorized or approved for use.
How Well the Vaccine Works
- Based on evidence from clinical trials, the Pfizer-BioNTech vaccine was 95% effective at preventing laboratory-confirmed COVID-19 illness in people without evidence of previous infection.
- CDC will continue to provide updates as we learn more about how well the Pfizer-BioNTech vaccine works in real-world conditions.
Clinical Trial Demographic Information
Clinical trials for the Pfizer-BioNTech vaccine included people from the following racial and ethnic, age, and sex categories:
- 81.9% White
- 9.8% African American
- 4.4% Asian
- <3% other races/ethnicities
- <1% Native Hawaiian or Other Pacific Islander
- <1% American Indian or Alaska Native
- 73.2% Not Hispanic or Latino
- 26.2% Hispanic of Latino
- <1% Not Reported
Age and sex breakdown:
- 50.6% male
- 49.4% female
- 21.4% 65 years and older
- 57.9% 16 to 55 years
- 41.8% 55 years and older
- 21.4% 65 years and older
- 4.3% 75 years and older
The most frequent underlying medical conditions were obesity (35.1%), diabetes (8.4%), and pulmonary disease (7.8%).