Impact of rotavirus vaccination in Malawi from 2012 to 2022 compared to model predictions

Abstract

Abstract Rotarix® vaccine was introduced into the Malawi national immunization program in October 2012. We analyzed data on children 90% with two doses by July 2014, and declined to a low of ~80% in October 2020 before returning to pre-pandemic levels by July 2021. Our models captured the post-vaccination trends in RVGE incidence. Comparing observed RVGE cases to the model-predicted incidence without vaccination, overall effectiveness was estimated to be modest at 36.0% (95% prediction interval: 33.6%, 39.9%), peaking in 2014, and was highest in infants (52.5%; 95% prediction interval: 50.1%, 54.9%). Our mathematical models provide a validated platform for assessing strategies to improve rotavirus vaccine impact in low-income settings.