Indirect protection from rotavirus vaccines: a systematic review

Introduction: Rotavirus vaccines may provide indirect protection by reducing transmission in the population and thus reducing disease burden. Method(s): This systematic review summarizes estimates of indirect protection from rotavirus vaccines and the methods used to obtain these estimates. Result(s): We identified 71 studies published between 2009 and 2022 that provided 399 estimates of indirect protection from rotavirus vaccine. Most estimates (73%) evaluated hospitalizations due to rotavirus gastroenteritis as the outcome and unvaccinated children <5 years old as the agegroup (64%), but there was considerable variability in methods to evaluate indirect protection. For hospitalizations due to rotavirus gastroenteritis among unvaccinated children <5 years old, the median incidence rate ratio was 0.60 (IQR: 0.40-0.87, n = 110 estimates), the median relative percent change in percent positivity was 25% (IQR: 13-44%, n = 49 estimates), and the median relative percent change in absolute number of rotavirus positive tests or rotavirus-specific International Classification of Diseases codes was 42% (IQR: 16-66%, n = 40 estimates). Conclusion(s): These findings broadly suggest rotavirus vaccines provide some indirect protection. There is a need to standardize measurement of indirect rotavirus vaccine protection, particularly using consistent outcomes and metrics, and stratifying results by standardized age groups and years since vaccine introduction. Copyright © This work was authored as part of the Contributor's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.