Efficacy and safety evaluations of Ebola vaccines in Guinea

The proposed study aims to evaluate Ebola vaccine efficacy and the use of ring vaccination as a delivery strategy.Ring vaccination refers to targeted vaccination of a defined geographical area (a ring) where a newly diagnosed case of an infectious disease originated. This strategy can provide a buffer of immune people to prevent further spread. To compare the risk of Ebola disease in vaccinated and non-vaccinated groups, rings will be randomised to vaccination immediately or at 30 days, with both groups receiving infection prevention and control advice at baseline, alongside contact tracing activities done outside the trial. The study will be conducted in a prefecture in Guinea, with engagement of the local community and in collaboration with the Guinean authorities.In addition, we will offer vaccination to frontline workers (FLWs) in the study area. This is in line with the prevailing consensus that FLWs should have early access to vaccines and this should be offered within a study to inform safety and efficacy. We will compare disease incidence among vaccinated FLWs with historic data on EVD incidence in a comparable cohort of FLWs. We believe this will be crucial to the success of the study at large.