Scientists at the National Institutes of Health (NIH) have developed an experimental vaccine against the Ebola that offers protection against the current strain of the virus – EBOV-Makona – in cynomolgus macaques. Complete effectiveness was possible if the vaccine was administered at least seven days prior to exposure, and partial protection was seen if administered three days before exposure to the virus.
The Prepared Ebola vaccine – VSV-EBOV
Vesicular stomatitis virus (VSV) is an animal virus that mainly affects cattle. VSV has been productively tested as an experimental vaccine against various strains of viruses. VSV-EBOV is a live-attenuated vaccine. It utilizes genetically engineered VSV to transport a gene of the Ebola virus (EBOV) that has been found to induce protective immunity in macaques.
Before this study, scientists had no data regarding the effects of administering VSV-EBOV to monkeys, and would the vaccine even be effective against EBOV-Makona, which has spread across West Africa. Studies on previous animal models demonstrated that VSV-EBOV was highly effective in protecting monkeys against the first strain of Ebola virus identified in 1976 in Mayinga, and also against EBOV-Kikwit, a strain that emerged in 1995 in Central Africa.
VSV-EBOV – Effectiveness And Future Prognosis
The new findings suggest that VSV-EBOV induces immune responses against all three strains of EBOV mentioned above. Scientists from National Institute of Allergy and Infectious Diseases Division of Intramural Research conclude that VSV-EBOV would also be equally effective against other strains of Ebola.
Researchers also observed that the experimental vaccine provided initial protection by stimulating innate host responses of fighting against virus particles. These fundamental responses conferred protection against EBOV-Makona within a week after vaccination. Moreover, animals vaccinated more than a week prior to exposure developed antibodies – adaptive immune response essential for long-term protection. Global clinical trials are currently underway to test the effectiveness of VSV-EBOV in humans.