Rotavirus Genotypes in the Postvaccine Era: A Systematic Review and Meta-analysis of Global, Regional, and Temporal Trends by Rotavirus Vaccine Introduction.

Background Even moderate differences in rotavirus vaccine effectiveness against nonvaccine genotypes may exert selective pressures on circulating rotaviruses. Whether this vaccine effect or natural temporal fluctuations underlie observed changes in genotype distributions is unclear. Methods We systematically reviewed studies reporting rotavirus genotypes from children <5 years of age globally between 2005 and 2023. We compared rotavirus genotypes between vaccine-introducing and nonintroducing settings globally and by World Health Organization (WHO) region, calendar time, and time since vaccine introduction. Results Crude pooling of genotype data from 361 studies indicated higher G2P[4], a nonvaccine genotype, prevalence in vaccine-introducing settings, both globally and by WHO region. This difference did not emerge when examining genotypes over time in the Americas, the only region with robust longitudinal data. Relative to nonintroducing settings, G2P[4] detections were more likely in settings with recent introduction (eg, 1–2 years postintroduction adjusted odds ratio [aOR], 4.39; 95% confidence interval [CI], 2.87–6.72) but were similarly likely in settings with more time elapsed since introduction, (eg, 7 or more years aOR, 1.62; 95% CI,.49–5.37). Conclusions When accounting for both regional and temporal trends, there was no substantial evidence of long-term vaccine-related selective pressures on circulating genotypes. Increased prevalence of G2P[4] may be transient after rotavirus vaccine introduction. [ABSTRACT FROM AUTHOR]