Validation Survey of Yellow Fever Reactive Mass Vaccination Campaign in Rural Gurage Zone, Southern Ethiopia 2021

Abstract Background: The Ethiopian public health institute reported a Yellow fever outbreak in March 2020 based on a single laboratory confirmed sample from Ethiopia's Southern nation nationalities and people region, Gurage Zone, Enor-ener district. About 702,906 people were targeted and 652,811 received the vaccine. The campaign administrative data coverage was 93%. This study validates the yellow fever vaccination coverage in the 13 districts. Method: A cluster survey was used to validate the yellow fever vaccination coverage. The sample size required was 816 people, assuming a two-sided test with a precision of 0.05, a design effect of 2.5, 17 respondents per cluster, a proportion of those with complete vaccinations based on previous administrative coverage of 93%, and a non-response rate of 5%. The sampling interval was calculated by dividing the total population of the districts by 48 (the desired number of clusters). Result: Only 813 (99.6 %) of the 816 study participants were included in the analysis. Overall, 97.5 % of people were immunized against Yellow Fever, with a 95 % confidence interval (0.962-0.985). The majority of responders (526 (64.7 %) were female, with a vaccination rate of 98.5 %. About 101 respondents (12.4 %; 95 % CI) were between the ages of 35 and 40. (10.2- 14.9). The majority of respondents (716 (89 %) with a 95 % CI (86-90) had the Yellow fever card, and 77 (9.4 %) claimed to be vaccinated, with the remaining 20 (2.6 %) not vaccinated. Yellow fever vaccine coverage was 96 % in Chaha district; 95 % CI (93.1-97.9), 97.7 % in Abeshge district; 95 % CI (94.2-99.3), 100 % in Wolkite; 95 % CI (94-100), 98.3 % in Enor-ener district; 95 % CI (95.8-99.5), and 100 % in Gunchire (89-100). The adverse events following immunization were fever 0.4%, headache 0.4% and seizure 0.1%. Conclusion: According to this survey, there were data disparities between the survey and administrative data in the mass vaccination program coverage estimate. The mass vaccination campaign against yellow fever in the selected five districts were successful since the estimated coverage exceeded the desired threshold of 80%.