Effectiveness of monovalent rotavirus vaccine against hospital-attended rotavirus gastroenteritis among children in Uganda

The underlying causes for lower rotavirus vaccine effectiveness (VE) in high-child-mortality settings are not well understood. Uganda introduced the human monovalent G1P[8] rotavirus vaccine (Rotarix) in June 2018. We determined the effectiveness of Rotarix against rotavirus diarrhea requiring hospital care among Ugandan children. We compared the vaccination status of children with laboratory-confirmed rotavirus (cases) and non-rotavirus (controls) diarrhea who were age-eligible to receive Rotarix and admitted to 3 hospitals in Uganda October 2018–December 2022. VE ([1–odds ratio of vaccination among cases and controls] x 100]) was calculated using unconditional logistic regression adjusting for age, birth month-year, and hospital. Among 187 cases and 622 controls, respectively, 93 % (173/187) and 93 % (579/622) had received ≥1 doses of Rotarix. Adjusted full-series (2 dose) VE against rotavirus diarrhea was 29 % (95 % confidence interval: −37 %–63 %) in children 4–59 months of age. Two-dose VE was 62 % (9 %–84 %) in infants 4–11 months of age and − 69 % (−401 %–43 %) in children 12–59 months of age (P = 0.20). VE against strains partially-heterotypic to the vaccine strain (including G3P[8], the most common curculating genotype) was 59 % (1 %–83 %). Routine Rotarix vaccination was effective in preventing hospital visits for rotavirus diarrhea among Ugandan infants, although protection was not sustained after the first year of life. Protection was demonstrated against partially heterotypic rotavirus strains. These results support the continued use of rotavirus vaccines in Uganda. Additional studies are needed to understand the lower rotavirus VE seen in Uganda and other high-mortality settings. •We report the effectiveness of rotavirus vaccine (Rotarix) among children in Uganda.•A complete series of Rotarix prevented severe rotavirus diarrhea among Ugandan infants.•We demonstrate effectiveness against partially-heterotypic strains, e.g., G3P[8].•We provide evidence for the support of the rotavirus vaccine program in Uganda.