We have a nurse in one of our clinics who gave separate doses of hepatitis A and hepatitis B vaccine in the gluteus. Are the doses of each antigen considered invalid? If so, can they be repeated at any time or do I need to count the spacing between doses from the date when the invalid dose was administered?

Although the gluteus muscle is not a recommended site for vaccination, in general, a dose given there can be considered valid. The exceptions to this general rule are hepatitis B and rabies vaccines, so the hepatitis B vaccine should not be counted in this situation. The hepatitis B vaccine can be repeated immediately. See the Advisory Committee on Immunization Practice’s (ACIP) “General Best Practices Guidelines for Immunization”, available at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/administration.html.