Dengue antibody in Thai children from maternally transferred antibody to acquired infection.

This prospective cohort study examined serotype-specific neutralizing serum antibodies to dengue in 55 maternal-newborn pairs, at 3, 6, 9, 12, 18, and 24 months, and again at 4 to 8 years of age. In all, 95% of the mothers had neutralizing antibody to at least one dengue serotype, and 92.7% of the maternally transferred antibody had disappeared in 12-month-old infants. In all, 31 infants had serologically confirmed dengue infection; 5 symptomatic and 29 inapparent infections were reported. The increasing trend of inapparent infections among the older age group warrants further study of the need for effective dengue vaccination beyond 2 years of age.