The effect of diarrhea on oral poliovirus vaccine failure in Brazil.

The effect of diarrhea on oral poliovirus vaccine (OPV) failure was evaluated using data from Brazil, where 728 infants were immunized at birth (OPV1) and approximately 6 (OPV2), 10 (OPV3), and 14 (OPV4) weeks. Recent diarrhea history was significantly associated with increased vaccine failure only after OPV2 for poliovirus types 2 and 3. In multivariate models, controlling for breast feeding, season of vaccine administration (type 3 only), maternal antibody (type 3 only), and immunization campaign exposure (type 3 only) strengthened this effect. Diarrhea at OPV receipt was associated with vaccine failure to poliovirus types 1 and 3 only after OPV2. These data support the current recommendation that children with diarrhea receive OPV and be reimmunized once their illness resolves. Expanding this recommendation to include children with a recent diarrhea history should be considered. While the effect of diarrhea on vaccine failure may be limited to OPV2, programmatic realities may preclude dose-specific recommendations.