Maternally transferred neutralising dengue antibodies in Thai infants: a pilot study.

In a dengue-endemic area, sera from 42 mother-infant pairs and sera collected from the infants at follow-up at the ages of 3 months (n =27), 6 months (n =34), 9 months (n =23) and 12 months (n =8) were tested for antibodies to four dengue serotypes using a plaque reduction neutralisation test (PRNT(50)), IgG ELISA and haemagglutination inhibition assay (HAI). The IgG ELISA and HAI tests were less sensitive than PRNT(50) in detecting low levels of antibodies. Levels of maternally transferred dengue neutralising antibodies in the cord sera were very high and identical to those in the mothers.