MedPageToday Study reinforces importance of vaccinating at-risk groups as early as possible, authors say, Vaccination with the Ebola Zaire vaccine (rVSVΔG-ZEBOV-GP; Ervebo) was associated with a significantly lower risk of death in patients with confirmed Ebola disease, even for those vaccinated shortly after exposure to the virus, a retrospective analysis found.
Among patients admitted to Ebola health facilities in the Democratic Republic of the Congo, the unadjusted case fatality rate (CFR) was 25.1% for vaccinated patients compared with 56.2% for unvaccinated patients (P<0.0001), Rebecca Coulborn, MPH, of Epicentre in Paris, and colleagues reported in Lancet Infectious Diseases.
In an adjusted analysis, protection against death increased as time elapsed from vaccination to symptom onset. However, even vaccination shortly before symptom onset was tied to a reduced risk of death compared with being unvaccinated:
- 27% vaccinated less than 2 days before symptom onset died (adjusted relative risk [aRR] 0.56, 95% CI 0.36-0.82, P=0.0046)
- 20% vaccinated 3-9 days before symptom onset died (aRR 0.44, 95% CI 0.29-0.65, P=0.0001)
- 18% vaccinated 10 or more days before symptom onset died (aRR 0.40, 95% CI 0.21-0.69, P=0.0022)
“Our evidence reinforces the importance of vaccinating populations who are at risk of exposure to Ebola virus as early as possible during outbreaks to reduce the risk of infection and severe complications of Ebola virus disease, including death,” the authors wrote.