Overall effect of a campaign with measles vaccine on the composite outcome mortality or hospital admission: A cluster-randomized trial among children aged 9-59 months in rural Guinea-Bissau

•Measles vaccine (MV) may reduce mortality and admissions beyond measles prevention.•For decades, MV has been distributed in campaigns to eliminate measles worldwide.•We assessed an MV campaign's effect in a cluster-randomized trial in Guinea-Bissau.•Mortality was lower than anticipated and MV did not reduce mortality or admissions.•MV's effects may differ by underlying disease patterns and other vaccine campaigns.