Ebola Outbreak Response in the DRC with rVSV-ZEBOV-GP Ring Vaccination

This study evaluates the efficacy of ring vaccination using the rVSV-ZEBOV-GP vaccine during the 2018–2020 Ebola virus disease outbreak in eastern Democratic Republic of Congo (DRC), a context marked by violence and community mistrust. A total of 1853 rings were formed around new cases, with 265,183 participants vaccinated. Most cases occurred within 9 days post-vaccination (380 cases), but rates dropped significantly after day 10. Only 32 cases were diagnosed between days 10–29, and 22 after day 29. The incidence rate post-day 10 was markedly lower than in the Guinea trial with delayed vaccination, reinforcing vaccine efficacy. Case fatality among vaccinees was substantially lower than among nonvaccinees (23% vs. 75%). No serious vaccine-related adverse events were reported, and ring vaccination proved feasible, effective, and dose-sparing even in difficult field conditions.

This study evaluates the efficacy of ring vaccination using the rVSV-ZEBOV-GP vaccine during the 2018–2020 Ebola virus disease outbreak in eastern Democratic Republic of Congo (DRC), a context marked by violence and community mistrust. A total of 1853 rings were formed around new cases, with 265,183 participants vaccinated. Most cases occurred within 9 days post-vaccination (380 cases), but rates dropped significantly after day 10. Only 32 cases were diagnosed between days 10–29, and 22 after day 29. The incidence rate post-day 10 was markedly lower than in the Guinea trial with delayed vaccination, reinforcing vaccine efficacy. Case fatality among vaccinees was substantially lower than among nonvaccinees (23% vs. 75%). No serious vaccine-related adverse events were reported, and ring vaccination proved feasible, effective, and dose-sparing even in difficult field conditions.