Pfizer Covid Vaccine Side Effects

The Pfizer-BioNTech COVID-19 vaccine can cause side effects, most of which are mild and temporary.^[1] Common side effects include:

• Pain, redness, or swelling at the injection site
• Tiredness or fatigue
• Headache
• Muscle pain
• Chills
• Joint pain
• Fever
• Swollen lymph nodes
• Nausea
• Feeling unwell
• Decreased appetite
• Vomiting or diarrhea
• Arm pain
• Dizziness
• Fainting following injection
• Irritability (especially in children)
• Febrile seizures (convulsions during a fever, rare in children)

These reactions are mostly mild and usually resolve within a few days.^[3] In clinical trials and real-world monitoring, such side effects were reported most frequently after the second dose.^[2]

Serious side effects are rare but may include:

• Severe allergic reactions, including anaphylaxis
• Non-severe allergic reactions such as rash, hives, itching, or swelling of the face
• Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart)

Myocarditis and pericarditis have occurred most often in adolescent and young adult males, typically within seven days following the second dose.^[1] The risk, while still low, is higher in young males (for example, estimated excess of 131–196 cases per 1 million young males vaccinated within a week post-dose).^[6] Symptoms of myocarditis or pericarditis include chest pain, shortness of breath, and palpitations. Seek medical attention if any of these occur soon after vaccination.^[3]

Other rare symptoms may include:

• Fainting or dizziness shortly after vaccination
• Persistent irritability, poor feeding, fatigue, abdominal pain, or cool/pale skin (especially in children)

The vast majority of people do not have serious side effects, and the benefits of vaccination in preventing COVID-19 illness outweigh these risks.^[5] Contact a healthcare provider for concerns about side effects or to report unusual or severe reactions.^[7]

References

• [1] 2024–2025 Formula COVID-19 Vaccine by Pfizer-BioNTech – CDC
• [2] Package Insert and FDA Approved Patient Labeling – COMIRNATY
• [3] Fact sheet for recipients and caregivers about pfizer-biontech – FDA
• [5] COVID Vaccine 2024-2025 (12 Yrs Up) (Pfizer) (PF) Intramuscular – WebMD
• [6] Benefit-risk assessment of COVID-19 vaccine, mRNA (Comirnaty) – PMC
• [7] 2024–2025 COVID-19 Vaccine by Pfizer-BioNTech – CDC