Immunogenicity and safety of ebolavirus vaccines in healthy adults: a systematic review and meta-analysis of randomized controlled trials

Background: This review aimed to systematically evaluate the immunogenicity and safety of the candidate Ebola virus vaccine (EVV).Methods: We searched five databases for randomized controlled trials (RCTs) evaluating the effects of EVV on healthy adults.The primary outcomes were relative risk (RR) of sero-conversion or sero-response of EVV in healthy adults between the groups that received EVV and the controls.Results: Twenty-nine RCTs (n = 23573) were included.There was a significant difference in RR of seroconversion of EVV (RR 13.18; 95% CI 11.28-15.41;I 2 = 33%; P < 0.01) between the two groups.There was a significant difference in RR of adverse events (AEs) of EVV (RR 1.49; 95% CI 1.27-1.74;I 2 = 88%; P < 0.01), although no difference in RR of serious AE (SAE) between the two groups.Subgroup analysis showed that there was no significant difference in RR of AEs for DNAEBO, EBOV-GP, MVA, and rVSVN4CT1 vaccines, compared with controls.Conclusions: The DNAEBO, EBOV-GP, MVA, and rVSVN4CT1 vaccines are likely to be safe and immunogenic, tending to support the vaccination against Ebola disease.These findings should provide muchneeded evidence for public health policy makers to develop preventive measures based on disease prevalence features and socio-economic conditions.