While much of the world is focused on COVID-19, it’s easy to forget that other deadly viruses are out there. Now, researchers have tested a novel vaccine candidate for Ebola in animals, which doesn’t contain live vectors and appears to be effective against all four species of the virus that infect humans.
Vaccines and treatments for the Ebola virus have been in development for decades, but efforts were accelerated after the worst outbreak on record occurred between 2013 and 2016, centralized in West Africa.
The most promising vaccine so far is rVSV-ZEBOV, which has been shown to have an almost 100-percent effectiveness rate against the Zaire species of Ebola virus. It’s made by genetically engineering a harmless virus to express a glycoprotein that the Zaire Ebola virus uses, which trains the patient’s immune system to fight off the deadly bug.
Although this vaccine is very effective against this most dangerous Ebola species, it has limited ability to fight off the other three species. The new vaccine candidate, on the other hand, can target all four known types of Ebola.
Instead of using live vectors, the researchers created a spherical virus-like particle (VLP) that’s made with glycoproteins from the Zaire and Sudan Ebola viruses. These particles induce an immune reaction against Ebola, but because they don’t have genetic material and don’t multiply, they won’t cause illness as a side effect.
In tests on rabbits, the team found that the new Ebola VLP vaccine generated antibodies that fought off all four Ebola species. Tests on rhesus macaques achieved similarly strong immune responses.
“This could be a significant advancement in the global effort to prevent or manage Ebola outbreaks, especially if this vaccine used alone or in combination with another Ebola vaccine results in long-term and durable protective immunity against different Ebola viruses,” says Karnail Singh, co-principal investigator on the study.
Of course, the work is still in the very early stages, so there’s no guarantee that the results will translate to humans. The team says that further preclinical testing will need to be conducted before clinical trials can begin.
The research was published in the Journal of Virology.
