Measles outbreak investigation in west Hararghie zone of Oromia region , Ethiopia ,2007

Abstract

Background
This epidemic investigation was conducted in West Harargie zone of Oromia Region, Ethiopia. The zone had a total population of 1,900,412 in 2007. Measles catch-up SIAs were conducted in 2002 followed by 2 rounds of follow up SIAs in 2005 and 2007 (with 93% administrative coverage in both rounds). The measles routine immunization administrative coverage has shown an improvement from 34% in 2002 to 71% in 2007. With an improving surveillance system there was no adequate documentation of measles outbreaks and mortality due to measles throughout the country. This paper describes the findings of an investigation of a confirmed measles outbreak in this zone between WHO epidemiological weeks 2 and 29 of 2007
Methods
A household retrospective surveys was conducted in 7 Woreda of west Harargie zone of Oromia region from 1August to 3 September 2007. A house-to-house search for measles cases was conducted in each village of the 8 Woredas where the measles epidemic was reported (from January to June of 2007). Guardian of the cases (ascertained based on the WHO cases definition) were interviewed based on the questionnaire. Data was collected by trained health workers. The data was checked by WHO surveillance officer. EPI2000 and SPSS statistical packages were used for data analysis. The investigation team carried out a time, place and person analysis, and estimated the case fatality rate, X2 test used whenever necessary.
Results
A total of 718 cases were identified and interviewed during the survey period; of which 54% are males and the same percentage is under age of five years old. 84.4 % of the cases were from 3 Woredas. Among the investigated patients, 579 (80.6%) were unvaccinated for measles, 96 (13.2 %) reported to have received at least one dose of measles vaccine. There were a total of 48 (6.7%) deaths and the cases fatality rate was highest between 12 and 23 months of age and in subjects older than 14 years. the case fatality rate is higher among the non vaccinated children.
Conclusions & recommendations
Despite availability of measles vaccine unvaccinated children are dying and the notification efficiency is still low. The routine surveillance system picks only fewer deaths than found by the outbreak investigation report. The surveillance system needs to be expanded up to community level and the outbreaks need to investigate appropriately and fully to document all cases and deaths. Late out break response immunization didn’t help. Early Intensified routine and selective immunization might have a better result with lesser cost.