Diarrhea and Bivalent Oral Polio Vaccine Immunity

Global eradication of poliomyelitis has proven to be elusive. Although 99% of cases have been eliminated since 1988, outbreaks continue to occur, and new tools are needed to accelerate eradication. One concern in this effort is that some populations have decreased immunogenicity to oral poliovirus vaccine (OPV). Past studies have shown decreased seroimmunity to trivalent OPV (tOPV) in children with diarrhea. In 2009, bivalent OPV (bOPV) was recommended for use in immunization campaigns, and will likely replace tOPV in routine immunization in 2016. However, the effect of diarrhea on seroconversion to bOPV has not been studied. This project evaluated the effect of diarrhea on seroconversion to bOPV among infants who reside in Nepal. The investigators conducted a prospective, interventional study that assessed immune response to bOPV among infants with and without diarrhea. Immune responses were compared among infants with and without diarrhea. This study will result in a better understanding of the factors that decrease the ability of some children to seroconvert to OPV and be protected from poliomyelitis infection.