Rotavirus Vaccine Effectiveness Stratified By National-Level Characteristics: An Introduction to the 24-Country...

Area of Science:

• Global Health
• Vaccinology
• Pediatric Infectious Diseases

Background:

• Rotavirus vaccines show variable effectiveness across different mortality settings.
• Limited data exists on vaccine effectiveness (VE) in specific subpopulations and for rare outcomes.
• Large-scale pooled analyses are crucial for understanding these disparities.

Purpose of the Study:

• To evaluate rotavirus vaccine effectiveness (VE) stratified by country-level child mortality rates.
• To assess VE across diverse subpopulations using a combined dataset.
• To clarify disparities in rotavirus vaccine performance globally.

Main Methods:

• Pooled data from 25 test-negative design case-control studies across 24 countries.
• Inclusion of children aged 3-59 months with medically-attended diarrhea.
• Logistic regression models used to estimate adjusted VE for complete and partial vaccine series, stratified by national under-5 mortality rates (U5M).

Main Results:

• Analysis included 6,626 rotavirus-positive cases and 19,459 rotavirus-negative controls.
• Complete-series VE was significantly higher in low/medium U5M countries (74%) compared to high U5M countries (46-52%).
• Partial-series VE estimates were lower than complete-series estimates.

Conclusions:

• Rotavirus vaccine performance exhibits heterogeneity across different child mortality levels.
• Complete-series vaccination is critical for maximizing protection against rotavirus illness.
• Findings underscore the importance of vaccination strategies in diverse global settings.