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Pfizer-BioNTech COVID-19 Vaccine Side Effects

Generic name: sars-cov-2 mrna (tozinameran) vaccine

Medically reviewed by Last updated on Apr 26, 2023.

Note: This document contains side effect information about sars-cov-2 mrna (tozinameran) vaccine. Some dosage forms listed on this page may not apply to the brand name Pfizer-BioNTech COVID-19 Vaccine.

Applies to sars-cov-2 mrna (tozinameran) vaccine: intramuscular suspension.


Intramuscular route (Suspension)

Although the licensed vaccine (Comirnaty®) is FDA-approved in patients aged 16 or older for 2 doses , Pfizer-BioNTech COVID-19 vaccine is an unapproved product authorized for emergency use in individuals aged 12 through 15 years and to provide a third dose to individuals aged 12 years or older who are solid organ transplant recipients or have an equivalent level of immunocompromise.

Serious side effects

Along with its needed effects, sars-cov-2 mrna (tozinameran) vaccine (the active ingredient contained in Pfizer-BioNTech COVID-19 Vaccine) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking sars-cov-2 mrna (tozinameran) vaccine:

More common

Less common


Incidence not known

Other side effects

Some side effects of sars-cov-2 mrna (tozinameran) vaccine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to sars-cov-2 mrna (tozinameran) vaccine: intramuscular suspension.


Very common (10% or more): Pain at injection site (78.3% to 90.5%), injection site swelling (up to 10.5%)

Common (1% to 10%): Swelling, injection site redness/redness[Ref]

Nervous system

Very common (10% or more): Headache (43.5% to 75.5%)

Uncommon (0.1% to 1%): Lethargy

Rare (0.01% to 0.1%): Bell's palsy

Postmarketing reports: Dizziness, syncope[Ref]

Bell's palsy occurred in 4 patients in the treatment group versus 2 patients in the placebo group. Onset of facial paralysis occurred on day 37 after dose 1 (patient only received one dose), and days 3, 9, and 48 after dose 2 in the treatment group; onset of facial paralysis was day 30 and 102 in the placebo group. Currently available information is insufficient to determine a causal relationship with the vaccine.[Ref]


Very common (10% or more): Fatigue (49.4 to 77.5%), use of antipyretic or pain medication (27.8% to 45.2%), fever of 38C or higher (4.1% to 24.3%)

Uncommon (0.1% to 1%): Malaise, asthenia[Ref]


Very common (10% or more): Chills (16.5% to 49.2%), new or worsened muscle pain (22.9% to 42.2%), new or worsened joint pain (11.8% to 24.3%)

Postmarketing reports: Pain in extremity (arm)[Ref]


Very common (10% or more): Diarrhea (up to 11.7%)

Common (1% to 10%): Nausea, vomiting

Uncommon (0.1% to 1%): Decreased appetite[Ref]


Postmarketing reports: Severe allergic reactions including anaphylaxis, other hypersensitivity reactions (e.g., rash, pruritus, urticaria, angioedema)[Ref]


Postmarketing reports: Pericarditis, myocarditis[Ref]


Uncommon (0.1% to 1%): Hyperhidrosis, night sweats[Ref]


Uncommon (0.1% to 1%): Lymphadenopathy[Ref]


Uncommon (0.1% to 1%): Decreased appetite[Ref]

Frequently asked questions


1. "Product Information. Pfizer-BioNTech COVID-19 Vaccine PF (SARS-CoV-2 (COVID-19) mRNA BNT-162b2 vaccine)." Pfizer Inc., Madison, NJ.

2. (2022) "Product Information. Pfizer-BioNTech COVID-19 Vaccine PF (SARS-CoV-2 mRNA (tozinameran) vaccine)." Pfizer Inc.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.