Immediate hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines: Reports to VAERS

Adult females may be at higher risk of hypersensitivity reactions after influenza vaccination than men. Although the risk of hypersensitivity reactions following 2009 pandemic influenza A (H1N1) vaccines was low, all clinics administering vaccines should be familiar with treatment guidelines for these adverse events, including the use of intramuscular epinephrine early in the course of serious hypersensitivity reactions.