Conference abstract

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

Pan African Medical Journal - Conference Proceedings. 2017:6(14).20 Dec 2017.
doi: 10.11604/pamj-cp.2017.6.14.496

Contact the corresponding author
Keywords: Disease outbreaks, measles, risk factors, Uganda
Plenary

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

Robert Majwala1,&, Lydia Nakiire1, Daniel Kadobera1, Alex Riolexus Ario1

1Uganda Public Health Fellowship Program, Kampala, Uganda

&Corresponding author
Robert Majwala, Uganda Public Health Fellowship Program, Kampala, Uganda

Abstract

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-person’s likely exposure period (7-21 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 < 5 years (AR = 14/10,000) were the most affected of all age groups. The epidemic curve indicated a propagated outbreak. 32% (13/41) of case-persons and 13% (21/161) of control-persons went to one of the four water collection sites (by themselves or with parents) during the case-patients’ likely exposure period (OR M-H= 5.0; 95% CI = 1.5 - 17). The effectiveness of the single-dose measles vaccine was 75% 95% CI = 24 - 92); vaccination coverage was 68% (95% CI = 61 - 76).

Conclusion: exposures at water collection sites might have contributed to propagation of this outbreak. Low vaccine effectiveness and vaccination coverage facilitated measles transmission. We recommended intensifying measles vaccination for young children, advising residents with fever and rash to avoid going public gatherings including water collection sites, and introducing a two-dose measles vaccine in routine vaccination schedule.