The Ebola vaccine can protect people from dying of the disease even if they were already infected at the time, they were given the jab, according to a new study.
The research, based on data from the 2018–2020 Ebola outbreak in the Democratic Republic of the Congo (DRC), showed that the risk of dying of Ebola was halved among people who had been vaccinated with a single dose of the rVSV-ZEBOV vaccine before they started showing symptoms.
Ebola isn’t the first vaccine to be highly effective post-exposure – so-called ‘therapeutic vaccines’ given after infection rather than before have been used with rabies, measles and smallpox.
Even people who had been vaccinated just a day or two before they got sick were protected, despite the fact that it wouldn’t have been enough time for their immune systems to launch a full-blown response to the vaccine – scientists believe our bodies need about ten days to do this. The death rate among people who had been vaccinated two or fewer days before their symptoms developed was 27percent, compared to 56percent in those who were unvaccinated.
The study was conducted by researchers at Médecins Sans Frontières, in collaboration with the Institut National de Recherche Biomédicale (INRB) and the Ministry of Health of the Democratic Republic of the Congo. It was published in The Lancet Infectious Diseases.
The researchers noted that people who had been vaccinated had lower virus levels than those who hadn’t been vaccinated, which was likely a key factor in protecting them.
The Merck-manufactured vaccine was given to 40,000 people over the course of the DRC outbreak, and as it is 95percent effective, it played a key role in ending the epidemic.
