Immunogenicity and safety of an inactivated hepatitis A vaccine when coadministered with measles-mumps-rubella and varicella vaccines in children less than 2 years of age.

Background: Hepatitis A vaccination in early childhood has reduced hepatitis A transmission. Coadministration of hepatitis A vaccine with other childhood vaccines may assist completion of the age-appropriate immunization schedule. We assessed the immunogenicity and safety of an inactivated hepatitis A virus vaccine when coadministered with measles-mumps-rubella (MMR) and varicella vaccines in children less than 2 years of age.

Methods: In this open-label, randomized, multicenter study, 3 groups of healthy children 15 months of age received either 2 doses of hepatitis A vaccine 6 to 9 months apart (n = 324), hepatitis A vaccine coadministered with MMR and varicella vaccines and a second dose of hepatitis A vaccine 6 to 9 months later (n = 462), or MMR and varicella vaccines followed 6 weeks later by 2 doses of hepatitis A vaccine 6 to 9 months apart (n = 455). Immune responses were evaluated at baseline, 31 days after the second dose of hepatitis A vaccine, and 42 days after MMR and varicella vaccine administration. Solicited, unsolicited, and serious adverse events were collected.

Results: After 2 doses of hepatitis A vaccine, nearly all subjects in all groups were seropositive (≥99%). Coadministration of hepatitis A vaccine with MMR and varicella vaccines did not impact the immunogenicity of any of the vaccines and was well tolerated.

Conclusions: The immune response to hepatitis A vaccine and US-licensed MMR and varicella vaccines is not adversely affected when coadministered in children 15 months of age.