
Abstract Background We conducted a trial in Nigeria to assess the immunogenicity of the new bivalent oral poliovirus vaccine + inactivated poliovirus vaccine (bOPV+IPV) immunization schedule and gains in type 2 immunity with addition of second dose of IPV. The trial was conducted in August 2016–March 2017, well past the trivalent OPV-bOPV switch in April 2016. Methods This was an open-label, 2-arm, noninferiority, multicenter, randomized, controlled trial. We enrolled 572 infants aged ≤14 days and randomized them into 2 arms. Arm A received bOPV at birth, 6, and 10 weeks, bOPV+IPV at week 14, and IPV at week 18. Arm B received IPV each at 6, 10, and 14 weeks and bOPV at 18 weeks of age. Results Seroconversion rates for poliovirus types 1 and 3, respectively, were 98.9% (95% confidence interval [CI], 96.7–99.8) and 98.1% (95% CI, 88.2–94.8) in Arm A and 89.6% (95% CI, 85.4–93.0) and 98.5% (95% CI, 96.3–99.6) in Arm B. Type 2 seroconversion with 1 dose IPV in Arm A was 72.0% (95% CI, 66.2–77.3), which increased significantly with addition of second dose to 95.9% (95% CI, 92.8–97.9). Conclusions This first trial on the new Expanded Program on Immunization (EPI) schedule in a sub-Saharan African country demonstrated excellent immunogenicity against poliovirus types 1 and 3 and substantial/enhanced immunogenicity against poliovirus type 2 after 1 to 2 doses of IPV, respectively.
Infant, Newborn, Infant, Nigeria, Antibodies, Viral, Poliovirus, Poliovirus Vaccine, Inactivated, Poliovirus Vaccine, Oral, Major Article, Humans, Vaccines, Combined, Child, Immunization Schedule, Poliomyelitis
Infant, Newborn, Infant, Nigeria, Antibodies, Viral, Poliovirus, Poliovirus Vaccine, Inactivated, Poliovirus Vaccine, Oral, Major Article, Humans, Vaccines, Combined, Child, Immunization Schedule, Poliomyelitis
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