Seroprevalence of Antibodies to Measles, Mumps and Rubella (MMR) Vaccines in Previously Vaccinated Human Immunodeficiency Virus-Infected Children and their Control Counterparts

Abstract

Background: Concerns remain regarding immunity to measles, mumps and rubella in HIV-infected children and need for booster doses during later adolescent-hood or young adulthood. Methods: We evaluated measles, mumps and rubella antibodies in 13 HIV- infected and 13 age-matched control children. All children had received 2 doses of the measles, mumps and rubella (MMR) vaccine. Anti-measles, mumps, and rubella antibody levels were assessed by ELISA at a mean of 30 months in the HIV-infected group and 27 months in the control children, following a second dose of the MMR vaccine. MMR antibodies considered to be protective levels were >1.1 ODR (Optical Density Ratio) for measles and mumps and >9.9 IU/ml for rubella. Results and Conclusions: Of the thirteen HIV-infected children, only four (31%) (p=0.01) had protective level (>1.11 ODR) of antibodies to measles and five (38%) (p=0.04) had protective level of antibodies to mumps compared to eleven (85%) of the thirteen controls. Although the prevalence of protective immunity (>9.9 IU/ml) for rubella was comparable in HIV-infected and control children, antibody levels were significantly lower (p=0.01) in HIVinfected children compared to their control counterparts. Our study results show that approximately seventy percent of HIV-infected children and adolescents compared to their control counterparts, remain susceptible to measles and mumps, despite two doses of the MMR vaccine. We therefore, recommend that booster doses of MMR vaccine be considered in HIV- infected children and adolescents when exposed to outbreaks of these infectious diseases in the US. Further prospective and larger studies may need to be conducted in HIV-infected children to determine if lower immunities in this group are due to primary vaccine failure or waning immunity.