The effect of diarrheal disease on bivalent oral polio vaccine (bOPV) immune response in infants in Nepal

Abstract Background A globally-coordinated phase out of all type 2 containing oral polio vaccine (OPV) is planned for April 2016 during which bivalent 1 + 3 OPV (bOPV) will replace trivalent OPV (tOPV) in routine immunization schedules and campaigns. Diarrhea impairs the immune response to tOPV, but the effect of diarrhea on bOPV is unknown. Methods Infants aged 6 weeks to 11 months, who had received Results Infants with diarrhea, versus those without diarrhea, had reduced response for poliovirus types 1 (56% [87/156] vs 66% [109/164]) and 3 (34% [70/209] vs 52% [122/236]). After adjusting for other factors, infants with diarrhea had significantly reduced response for type 3 (odds ratio [OR] = 0.44, 95% CI 0.29–0.68), as did infants with >5 loose stools per day (OR = 0.36, 95% CI 0.21–0.62). Conclusions Diarrhea reduced the immune response to bOPV. Provision of additional doses of polio vaccine is necessary to maintain high population immunity in areas with high prevalence of diarrheal disease. Clinical trial registry This study is registered at clinicaltrials.gov as NCT01559636 .