Rubella outbreak investigation in Kuyu District North Shoa Zone, Oromia Region, Ethiopia, 2018: Community based case control study

Abstract

Background: Rubella is a vaccine preventable disease that goes unnoticed and result significant morbidity, mainly infection during pregnancy with serous consequence to the fetus. Despite increased episodes of rubella epidemics (127 rubella virus outbreaks) 2009–2015, rubella national vaccination is not yet introduced in Ethiopia. In January16/2018, an increase of fever and rash cases reported from Kuyu District of Oromia. We investigated the outbreak to confirm rubella, determine risk factors, and guide interventions. Methods & Materials: We identified Rubella cases from health centers in Kuyu district and conducted case control study (1:2 cases–controls) with 150 participants, from March 12–15/2018. Cases were having at least fever, rash and laboratory confirmed cases. We collect serum sample for confirmation of measles finally confirmed for rubella. Controls were matched-age (<15 years) from neighbors selected purposively. We interviewed parents using a structured questionnaire and observed housing condition. Variables include sex, age, vaccination status, family size, contact history, housing condition and travel history. Simple logistic regression was used to select candidate variable at p-value <0.25. We identified independent risk factors at P<0.05 with AOR and 95% CI by multivariable logistic regression. Results: We identified 50 case-patients (with no death) and Seven (14%) confirmed cases (rubella IGM positive). Among <15 yearrs patient-cases, Attack rate was higher for under five years age group. Family size of >5(AOR = 2.4 (95% CI; 1.5–4.11)), not well ventilated living room (AOR = 4.7 (95%CI; 3.43–8.12)), history of contact with rash peoples (AOR = 2.2 (95%CI: 1.6-3.5)) and no history of vitamin A supplementation (AOR = 2.9 (95%CI; 1.7–2.6) were significant risk factors for rubella infection. Conclusion: We identified rubella Outbreak in children less than 15 years in rural area. Crowded living condition, large family size, having diarrhea in the last 14 days, not receiving Vitamin A in the last 6 months and contact with peoples with symptom of rubella were the major factors driven the outbreak. We recommended the introduction of Rubella national immunization program, and advocated rubella policy and strengthening surveillance for congenital rubella syndrome and Rubella.