Dynamics of maternally transferred antibodies against measles, mumps, and rubella in infants in Sri Lanka

Abstract

BackgroundDetermining the dynamics of maternally transferred antibodies against measles, mumps, and rubella infections in infants is important for making evidence-based policy decisions regarding the timing of vaccination. MethodsThe levels of serum immunoglobulin G (IgG) developed against measles, mumps, and rubella infections were assessed using commercial ELISA kits in mother–newborn pairs (n = 294) and 6–12-month-old infants (n = 280) recruited from Colombo District, Sri Lanka. Antibody levels of mothers and their newborns were assessed with respect to sex and parity. Antibody levels and the protection conferred were assessed in a sample of infants who completed 6–12 months of age in relation to their age and sex. Antibody levels were compared between different age and sex groups using the Mann–Whitney U-test, and correlations of antibody titers were performed using the Spearman correlation test. ResultsThe prevalence rates of seropositivity for measles, mumps, and rubella were 91.5%, 89%, and 88%, respectively, in mothers, and 95%, 91.5%, and 93%, respectively, in their newborns. The newborns had mean IgG levels exceeding those of the mothers (P < 0.001). Mothers with natural infections had higher antibody levels compared to vaccinated mothers, which resulted in a higher level of maternal transfer. All of the infants who were 9–10 months of age or older were seronegative for measles, all of those who were 10–11 months of age or older were seronegative for rubella, and all of those who were 11–12 months old were seronegative for mumps. ConclusionsThe maternal transfer of antibodies to newborns is efficient and renders protection until the infants are 6–7 months old in the case of mumps and rubella and 7–8 months old in the case of measles. Hence infants remain vulnerable to infections before the first dose of the MMR vaccine.