A measles outbreak propagated by children congregating at water collection points: Mayuge District, Eastern Uganda, October 2016

Introduction: on 12 October, 2016 a measles outbreak was reported in Mayuge district. We investigated the outbreak to identify risk factors, evaluate vaccination coverage and vaccine effectiveness, and recommend evidence-based control measures. Methods: we defined a probable case as onset of fever (≥3 days) and generalized rash, plus ≥1 of the following: conjunctivitis, cough, runny nose in a resident of Mayuge (population: 480,079). A confirmed case was a probable case with measles-specific IgM (+) not explained by vaccination. We reviewed medical records and conducted active community case-finding. In a case-control investigation involving probable cases, age and village-matched controls, we evaluated risk factors for transmission during the case-persons likely exposure period (721 days prior to rash onset). We estimated vaccine effectiveness (VE) using the formula: VE ≈ 100 (1-ORprotective). We calculated vaccination coverage using the percent of controls vaccinated. Results: we identified 62 probable cases (attack rate [AR] = 4.0/10,000), including 3 confirmed. Males and females had similar ARs. Children