Impact of recurrent outbreaks of Ebola virus disease in Africa: a meta-analysis of case fatality rates

Abstract

Objectives: Between 2010 and 2020, Africa witnessed several outbreaks of Ebola virus disease (EVD), each presenting with varying case fatality rate (CFR) and other socio-economic impacts. This study aims to summarize the CFR and identify potential factors that influenced the severity of EVD outbreaks in Africa.

Study design: This was a systematic review and meta-analysis of EVD outbreaks published between January 2010 and March 2020, using Web of Science, Scopus, and PubMed databases.

Methods: Only English-language articles and reports, including the number of cases and deaths during the outbreak in Africa, were considered. The quality of the included articles was assessed using Murad's quality assessment tool. The analysis was conducted using Stata (version 12), pooled effect sizes were calculated using the random-effects model, and heterogeneity was tested for using the I² statistic.

Results: Thirteen studies with 32,300 cases and 13,727 deaths were identified, whose pooled CFR was 60% (95% confidence interval [CI]: 47-73%). The most EVD-affected countries were the Democratic Republic of Congo with five outbreaks and a pooled CFR of 65% (95% CI: 59-71%), followed by Uganda with three outbreaks and CFR of 83% (95% CI: 60-99%). Zaire ebolavirus caused the most outbreaks (10), with a CFR of 58% (95% CI: 45-71%). Besides, outbreaks with fewer than 1000 cases reported a higher CFR rate (65%, 95% CI: 54-75%) compared with those with more cases (51%, 95% CI: 33-69%).

Conclusion: The study has revealed a considerably high CFR caused by the recurrent EVD outbreaks in Africa. It also notes an implementation gap in the prevention and control strategies and thus identifies a need to strengthen the surveillance systems and response mechanisms to enable early detection and prompt control of future outbreaks.

Keywords: Africa; Case fatality rate; Ebola virus disease; Meta-analysis; Outbreak.