If soneone has an alergic reaction to a covid vaccine, does it have any bearing on whether it will be effective?

An allergic reaction to the first Covid vaccine should not affect its effectiveness, but it is a contraindication to receiving further Covid vaccines. It has been shown that each subsequent Covid vaccine increases the immunity to Covid 19 virus, as do actual infections. With only one vaccination, an individual should take other precautions to avoid infection, such as masking and avoiding crowds.

No, It is probably a reaction to one of the contents . Good Luck

There is no egg content in the vaccine, so it is something else you are allergic to. See an allergist for testing before a booster shot.

A severe allergic reaction, such as anaphylaxis (throat swelling) or angioedema (eyelids/tongue/lips swelling), that occur within 2 hours of a COVID-19 vaccine is concerning. The question about whether it will be effective depends on whether it is safe to take the full series (2 doses for Moderna/Pfizer or 1 dose with J&J) and whether it is safe for subsequent booster doses