Abstract
BACKGROUND: Following the 2016 global cessation of oral poliovirus vaccine type 2, outbreaks of circulating vaccine-derived poliovirus type 2 have posed significant public health challenges. The novel oral poliovirus vaccine type 2 (nOPV2), developed for enhanced genetic stability, lacks comprehensive pediatric data. OBJECTIVE(S): To systematically evaluate nOPV2 immunogenicity and safety in under-immunized pediatric populations through Bayesian meta-analysis. METHOD(S): We searched five databases from 2015 to 2025 for RCTs and observational studies of nOPV2 in children under 18 years from under-immunized populations. Bayesian single-arm meta-analyses were performed. RESULT(S): Five studies (four RCTs, one cohort) with 10,421 children from Bangladesh, The Gambia, and the Dominican Republic were included. Pooled seroconversion rates ranged from 65.8% to 81.5%. Severe adverse events after nOPV2 vaccination yielded a pooled proportion of 0.01 (95% CI: 0.00-0.02), mild events occurred in 7.8%, and viral shedding was 64.7%. CONCLUSION(S): nOPV2 shows robust immunogenicity and excellent safety, supporting its role in outbreak control and global polio eradication. CLINICAL TRIAL NUMBER: Not applicable.Copyright © 2026. The Author(s).
