Immunogenicity and safety of novel oral polio vaccine type 2 (nOPV2) in pediatric populations: a systematic review and Bayesian meta-analysis

Q: What is the clinical evidence from this study?

Study design: Meta-Analysis. Population: Poliovirus type 2 immunization (n=10421). Intervention: novel oral polio vaccine type 2 (nOPV2) vs. Traditional oral poliovirus vaccines, placebo, or no intervention (single-arm meta-analysis). Primary outcome: Seroconversion rate (four-fold or greater rise in neutralizing antibody titers) (95% CI 78.2-84.6).

Q: What does this research mean for the field?

The novel oral poliovirus vaccine type 2 (nOPV2) demonstrates robust immunogenicity and excellent safety in under-immunized pediatric populations. Novelty: ClaimNovelty.SYNTHESIS. Consensus alignment: ConsensusAlignment.NEUTRAL.

Jose Luis Boene; Letícia Rocha Campos; G. Carpi; Monica Muhawenimana; Sandra Helena Machado; Nilsa de Deus; Adilson Fernando Loforte Bauhofer

doi:10.1186/s12879-026-13584-0

May 25, 2026BMC Infectious DiseasesOpen Access

Immunogenicity and safety of novel oral polio vaccine type 2 (nOPV2) in pediatric populations: a systematic review and Bayesian meta-analysis

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Key result

nOPV2 achieves ~82% seroconversion and excellent safety in under-immunized pediatric populations.

95% CI 78.2-84.6
n=10,421

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Why the study?

Following the 2016 global cessation of oral poliovirus vaccine type 2, circulating vaccine-derived outbreaks emerged, but comprehensive pediatric data on the novel oral poliovirus vaccine type 2 were lacking.

Does novel oral poliovirus vaccine type 2 (nOPV2) provide adequate immunogenicity and safety in under-immunized pediatric populations?

Key Points

To systematically evaluate the immunogenicity and safety profiles of the novel oral poliovirus vaccine type 2 (nOPV2) in under-immunized pediatric populations.
Searched five databases from 2015 to 2025 for randomized controlled trials and observational studies evaluating nOPV2 in children under 18 years from under-immunized populations.
Identified five studies (four randomized controlled trials, one prospective cohort) comprising 10,421 children aged 1–59 months in Bangladesh, The Gambia, and the Dominican Republic.
Performed Bayesian single-arm hierarchical meta-analyses using Markov Chain Monte Carlo methods to synthesize proportions for seroconversion, adverse events, and viral shedding.
Pooled seroconversion rates ranged from 65.8% (95% CrI: 42.1-85.2%) in the random-effects model to 81.5% (95% CrI: 78.2-84.6%) in the beta-binomial model, with individual studies reporting rates between 65.8% and 94.1%.
Severe adverse events yielded a pooled proportion of 0.01 (95% CI: 0.00–0.02; I² = 92%), while mild adverse events occurred at a pooled rate of 7.8% (95% CrI: 6.2-9.6%).
Poliovirus viral shedding among vaccinated children reached a pooled rate of 64.7%.

Study Design

Type

Meta-Analysis (n=10,421)

Multicenter

Yes

Structured PICO

Does novel oral poliovirus vaccine type 2 (nOPV2) provide adequate immunogenicity and safety in under-immunized pediatric populations?

P

Population

10,421 children under 18 years from under-immunized populations across 5 studies (4 RCTs, 1 cohort)

I

Intervention

novel oral poliovirus vaccine type 2 (nOPV2)

O

Outcome

Immunogenicity (seroconversion rates) and safety (severe adverse events, mild events, viral shedding)safety

nOPV2 demonstrates robust immunogenicity and excellent safety in under-immunized pediatric populations, supporting its use for global polio outbreak control.

Limitations

Small number of studies (n=5) reduces statistical power
Exclusion of the Panama phase 2 trial evaluating early candidate formulations
Most included studies assessed only short-term outcomes (≤6 months), limiting conclusions on long-term immunity
Geographic concentration in three countries may restrict generalizability
Maternally derived antibodies in neonatal populations may have influenced seroconversion estimates
Substantial heterogeneity in baseline immunity, measurement timing, and population characteristics

Implication

Supports nOPV2 use for pediatric polio outbreak control; extends RCT evidence to under-immunized populations.

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 To systematically evaluate nOPV2 immunogenicity and safety in under-immunized pediatric populations through Bayesian meta-analysis. Methods 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. Results 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%. Conclusions nOPV2 shows robust immunogenicity and excellent safety, supporting its role in outbreak control and global polio eradication. Clinical trial number Not applicable.

Discussion

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Cite This Study

Boene et al. (2026) conducted a meta-analysis in Poliovirus type 2 immunization (n=10,421). novel oral polio vaccine type 2 (nOPV2) vs. Traditional oral poliovirus vaccines, placebo, or no intervention (single-arm meta-analysis) was evaluated on Seroconversion rate (four-fold or greater rise in neutralizing antibody titers) (95% CI 78.2-84.6). The novel oral polio vaccine type 2 (nOPV2) demonstrated robust immunogenicity with a pooled seroconversion rate of 81.5% and an excellent safety profile in under-immunized pediatric populations.

synapsesocial.com/papers/6a168f850c924ddd1bd5a4ba https://doi.org/10.1186/s12879-026-13584-0

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Immunogenicity and safety of novel oral polio vaccine type 2 (nOPV2) in pediatric populations: a systematic review and Bayesian meta-analysis

Figures

Key Points

Study Design

Structured PICO

Limitations

Implication

Abstract

Discussion

Cite This Study

Immunogenicity and safety of novel oral polio vaccine type 2 (nOPV2) in pediatric populations: a systematic review and Bayesian meta-analysis

Figures

Key Points

Study Design

Structured PICO

Limitations

Implication

Abstract

Discussion

Cite This Study

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