Treatment of enteric infections among Indian infants to improve their response to oral poliovirus vaccine

The immunogenicity and effectiveness of oral poliovirus vaccine is impaired in low-income compared with high-income countries. The high prevalence of intestinal pathogens and associated environmental enteropathy has been hypothesised to contribute to this problem. We performed a double-blind, randomised, placebo-controlled trial of the effect of azithromycin on the immunogenicity of serotype-3 monovalent oral poliovirus vaccine given to healthy infants living in Vellore, India. Infants were considered eligible for enrolment if they were 6–11 months of age and lacked serum neutralising antibodies to serotype-3 poliovirus. After enrolment, infants were assigned at random (1:1) to received a 3-day course of oral azithromycin (10 mg/kg) or placebo, followed by serotype-3 monovalent oral poliovirus vaccine on day 14. The primary outcome was detection of serum neutralising antibodies to serotype-3 poliovirus on day 35. The trial is registered with the Clinical Trials Registry India, number CTRI/2014/05/004588.