THE EFFECT OF DIARRHEA ON ORAL POLIOVIRUS VACCINE FAILURE IN BRAZIL

The effect of diarrhea on oral poliovirus vaccine (OPV) failure was ev aluated using data from Brazil, where 728 infants were immunized at bi rth (OPVI) and similar to 6 (OPV2), 10 (OPV3), and 14 (OPV4) weeks. Re cent diarrhea history was significantly associated with increased vacc ine failure only after OPV2 for poliovirus types 2 and 3. In multivari ate models, controlling for breast feeding, season of vaccine administ ration (type 3 only), maternal antibody (type 3 only), and immunizatio n campaign exposure (type 3 only) strengthened this effect. Diarrhea a t 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 w ith a recent diarrhea history should be considered. While the effect o f diarrhea on vaccine failure may be limited to OPV2, programmatic rea lities may preclude dose-specific recommendations.