Scientists at Cincinnati Children's Hospital Medical Center have reported the successful preclinical results of a new vaccine against the dangerous zoonotic disease Ebola. This vaccine is exciting because it is potentially universal, effective against all four types of the Ebola virus known to infect humans.
As reported in the Journal of Virology, the team tested the new vaccine on rhesus macaques and found it elicits the right immune response against all four virus species, including the Zaire ebolavirus, which has the highest mortality rate of the ebolaviruses and has caused the largest number of outbreaks.
There are several other vaccines currently undergoing clinical trials. rVSV-ZEBOV was approved in the United States in December 2019. This vaccine is 97.5 percent effective, but it was designed to elicit an immune response specifically against the Zaire ebolavirus. A universal vaccine would help bridge the gap.
"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," Dr Karnail Singh, the study's co-principal investigator, said in a statement.
To create the vaccine, the team made a fake ebolavirus shell. The shell was covered in glycoproteins found on the surface of both the Zaire ebolavirus and the Sudan ebolavirus so that it would be recognized as an extraneous body. The shell itself did not contain any genetic material so it was harmless. This approach gave the immune system the knowledge of what to look for during infection from an ebola virus and produced a robust immune response. Although the team only used proteins from two viruses, they believe the approach will deliver immunity across all types, as their exterior envelope share common proteins.
While the results are promising, the road to becoming a fully-fledged vaccine is long. More preclinical trials are necessary to fully understand the effects of this approach. If those continue to show promise, it will then move to clinical trials in humans.
