Important: VAERS reports alone cannot determine if a vaccine caused an adverse event. Reports may contain incomplete, inaccurate, or unverified information. Correlation does not equal causation.
Allergic reactions to vaccines range from mild skin reactions to life-threatening anaphylaxis. While serious allergic reactions are extremely rare (1-5 per million doses), understanding the signs and knowing what to expect is important.
Injection site redness/swelling, mild rash or hives near injection site, itching. Usually resolves on its own within hours.
Widespread hives (urticaria), facial swelling, persistent itching. May require antihistamines. Consult healthcare provider.
Difficulty breathing, throat swelling, rapid heartbeat, dizziness, drop in blood pressure. Medical emergency — call 911. Treated with epinephrine.
Allergic reactions to vaccines are usually triggered not by the active ingredient (the antigen) but by other components:
You're asked to wait 15-30 minutes after vaccination so that if anaphylaxis occurs, it can be treated immediately. Anaphylaxis almost always occurs within this window. All vaccination sites are required to have epinephrine available.
The 30-minute wait is recommended for people with a history of anaphylaxis to any cause or a history of immediate allergic reaction to a previous dose or known vaccine component.
Anaphylaxis rates vary slightly by vaccine but are extremely rare across the board:
For context: the risk of anaphylaxis from common antibiotics like penicillin is about 1-5 per 10,000 — roughly 100x higher than from vaccines.
Most people with allergies — including food allergies, drug allergies, and environmental allergies — can safely receive vaccines. Specific guidance: