COVID-19 Vaccines and Allergic Reactions.If you have had a severe allergic reaction or an immediate allergic reaction—even if it was not severe—to any ingredient in an mRNA COVID-19 vaccine, As an example, 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.
Experts refer to severe allergic reactions as anaphylaxis.An immediate allergic reaction happens within 4 hours after getting vaccinated and may include symptoms such as hives, swelling, and wheezing (respiratory distress).Polysorbate is not an ingredient in either mRNA COVID-19 vaccine but is closely related to PEG, which is in the vaccines.