Passive immunity of premature infants against measles during early infancy

The aim of this study was to evaluate the presence of transferred measles a ntibodies and seronegativity rates during early infancy in premature newbor ns whose mothers had infection-induced immunity. The premature group was co mposed of 22 and 35 newborns of gestational ages less than or equal to 32 w k and >32 wk, respectively, and the control group consisted of 28 term newb orns. Enzyme-linked immunosorbent assay (ELISA) was used for the qualitativ e detection of IgG antibodies to measles virus. Mean cord blood relative va lues were significantly lower in both premature groups, less than or equal to 32 wk (p < 0.0001) and >32 wk (p < 0.001), when compared with term infan ts. No seronegative infant was found in the premature group at 2 mo of age. At 4 mo, the seronegativity rate was 27% for premature infants less than o r equal to 32 wk and 35% for those >32 wk. At 6 mo, seronegativity increase d to 86% and 74% for premature infants born at gestational ages less than o r equal to 32 wk and >32 wk, respectively. Forty-six percent of the term in fants became seronegative at that age. The differences between term infants and those in the two premature groups were statistically significant (p < 0.05 and p < 0.005). Premature infants, regardless of their prematurity deg ree, were thought to be more susceptible to measles infection than term one s at the age of 6 mo. policies For their protection from measles infection are still to be investigated.