Rotavirus Gastroenteritis Infection among Children Vaccinated and Unvaccinated with Rotavirus Vaccine in Southern China: A Population-Based Assessment

Abstract

Importance: Since 2000, the Lanzhou lamb rotavirus vaccine has been exclusively licensed in China for voluntary rotavirus gastroenteritis (RV-GE) prevention. Objective: To evaluate the association of the Lanzhou lamb rotavirus vaccination with RV-GE among children in southern China. Design, Setting, and Participants: This cross-sectional, ecological study was set in Guangzhou, China. Participants were infants possibly vaccinated (aged 2 months to 3 years) and the children ineligible for vaccination (aged ≥4 years). The study was conducted from May 1, 2007, to April 30, 2016, and the data analysis was conducted in July 2016. Main Outcomes and Measures: Annual median age at onset of RV-GE and seasonal distribution of incidence. Cases of RV-GE in Guangzhou, China, diagnosed from May 1, 2007, to April 30, 2016, and reported to the National Information System for Disease Control and Prevention were examined. Poisson regression models were fitted among 32452 children younger than 4 years and among 450 children who had been ineligible for vaccination, while controlling for secular trends, socioeconomic status, and meteorological factors. Logistic regression was used to assess the indirect effects provided by the vaccinated infants from 2009 to 2011 on unvaccinated infants aged 2 to 35 months based on a separate case-control data set. Results: During 9 seasons, 119705 patients with gastroenteritis were reported; 33407 were confirmed for RV-GE (21202 [63.5%] male, 32022 [95.8%] aged <4 years, and 31306 [93.8%] residing in urban districts). The median age at onset for all patients with RV-GE increased from 11 months during the 2007 season to 15 months during the 2015 season, and the onset, peak, and cessation of incidence were delayed. When citywide vaccination coverage in the prior 12 months was classified into high and low groups (≥8.36% vs <8.36%), the incidence rate ratio for the high coverage group decreased by 32.4% among children younger than 4 years (incidence rate ratio, 0.676; 95% CI, 0.659-0.693; P