Pentavalent rotavirus vaccine effectiveness among children in Shenzhen, China: A population-based test-negative design with directed acyclic graphs bias adjustment

Background

China's Notifiable Disease Reporting System comprehensively collects data on pediatric acute gastroenteritis cases from all levels of healthcare. This study evaluated the effectiveness of the pentavalent rotavirus vaccine against rotavirus gastroenteritis in children under five years of age during seasonal epidemic periods.

Methods

Using a test-negative design, we analyzed laboratory data from diarrhea patients aged 2–59 months who sought medical care in Longhua District, Shenzhen, Guangdong Province, China between January 2020 and March 2024. Vaccination history and potential confounders, including sex, household registration status, prematurity, and birth weight, were collected retrospectively. Directed acyclic graphs were used to identify adjustment variables. Vaccine effectiveness was calculated as (1 − adjusted odds ratio) × 100 % using unconditional logistic regression, comparing rotavirus-positive cases with rotavirus-negative controls.

Results

The incidence of rotavirus gastroenteritis peaked and then progressively declined from January 2020 through March 2023, with no seasonal resurgence observed in the first quarter of 2023. Analysis of 928 epidemic-season cases (674 RV+; 254 RV–) revealed an overall pentavalent rotavirus (RV5) vaccine effectiveness of 79.6 % (95 % CI: 68.9 %–86.6 %). Dose-specific vaccine effectiveness varied substantially: 1 dose vaccine effectiveness registered at 26.7 % (95 % CI: −162.1 %–79.5 %), rising to 76.6 % (95 % CI: 46.2 %–89.8 %) for 2 doses, and reaching 82.7 % (95 % CI: 72.2 %–89.2 %) for 3 doses. Age-stratified analysis showed vaccine effectiveness of 79.5 % (95 % CI: 56.8 %–90.3 %) in children aged 2–11 months, 83.8 % (95 % CI: 66.4 %–92.2 %) for 12–23 months, and 79.6 % (95 % CI: 68.9 %–86.6 %) in those aged 24–35 months, while vaccine effectiveness was 31.2 % (95 % CI: −251.8 %–86.5 %) in children aged 36–59 months.

Conclusions

A three-dose regimen of pentavalent rotavirus vaccine provides significant effectiveness against rotavirus gastroenteritis for children under 36 months of age during epidemic seasons, thereby alleviating the burden on public health systems.