If an infant got a dose of the adult formulation of HepB in error, should the dose be counted? When should the next dose be scheduled for this infant? Do we need to be concerned about a possible adverse event?

If an infant received an adult formulation of HepB (adult formulations contains more antigen than pediatric formulations), the dose may be counted as valid and does not need to be repeated. The next age-appropriate dose should be given on the usual schedule. Heplisav-B is an exception because it is not FDA-approved for use in children: if a dose of Heplisav-B is administered more than 4 days before the 18th birthday, the dose should not be considered valid and should be repeated using an age-appropriate formulation. Hepatitis B vaccines are very safe vaccines and no unusual adverse events would be expected because of this administration error.