581. Monovalent rotavirus vaccine efficacy against different rotavirus genotypes: a pooled analysis of Phase II and III trial data

Abstract

Abstract Background Rotavirus vaccine effects appear lower in countries with high child mortality rates and high diversity of rotavirus genotypes. Some evidence suggests diminished vaccine efficacy (VE) against the G2P[4] genotype, which is heterotypic with existing monovalent rotavirus vaccine formulations. Most studies assessing genotype-specific VE have been underpowered and inconclusive. Methods We pooled individual-level data from ten Phase II and III clinical trials of monovalent rotavirus vaccine containing G1 and P[8] antigens (RV1). We estimated VE against any-severity and severe (Vesikari score ≥11) rotavirus gastroenteritis (RVGE) using binomial and multinomial logistic regression models for three types of VE: non-specific VE against any RVGE; genotype-specific VE against specific genotypes; and RV1-typic VE against genotypes homotypic, partially heterotypic, or fully heterotypic with the RV1 G1 and P[8] antigens. Models were adjusted for oral poliovirus vaccination concomitant with RV1 vaccination and the country’s child mortality stratum. Results A total of 87,644 infants from 22 countries in the Americas, Europe, Africa, and Asia were included in analysis. VE against severe RVGE was 91% (95% confidence interval (CI): 87-94%). Genotype-specific VE ranged from 96% (95% CI: 89-98%) against homotypic G1P[8] to 71% (95% CI: 43-85%) against fully-heterotypic G2P[4]. VE against severe RVGE caused by partially heterotypic genotypes (92% (95% CI: 84-96%)) was similar to VE against the homotypic genotype, but VE against fully heterotypic genotypes was lower (83% (95% CI: 67-91%)). VE against any-severity RVGE was 82% (95% CI: 75-87%). Genotype-specific VE estimates against any-severity RVGE ranged from 94% (95% CI: 86-97%) against G1P[8] to 63% (95% CI: 41-77%) against G2P[4]. VE against any-severity RVGE was lower (83% (95% CI: 72-90%) against partially heterotypic genotypes, but lowest (63% (95% CI: 40-77%)) against fully heterotypic genotypes. Conclusion RV1 VE is diminished against fully heterotypic genotypes including G2P[4]. Disclosures Benjamin Lopman, PhD, Epidemiological Research and Methods, LLC: Advisor/Consultant.