Scientists from the National Institutes of Health (NIH), USA have reported that a single dose of an experimental vaccine against the Ebola virus (EBOV) protects Macaque monkeys from the current strain of the virus (EBOV-Makona) that infected over 27,000 people in Guinea, Sierra Leone, and Liberia.

The EBOV disease causes hemorrhagic fever; it is a severe and deadly disease affecting humans and primates. Additionally, EBOV is known to reside in the eyes of an infected person months after he/she has been declared Ebola-free.  

According to the World Health Organization (WHO), about 11,283 individuals have lost their lives following infection with EBOV. The epidemic started in Guinea in 2013 and spread to the neighboring countries. This particular epidemic has exposed weaknesses in mobilizing medical supplies and personnel to the affected areas and underscored the need for a preventive measure to deal with the deadly virus.

The research team from NIH used a genetically modified virus that affects cattle, known as the Vesicular Stomatitis Virus or VSV, as a platform for the vaccine. The vaccine, VSV-EBOV was tested in mice and Macaque monkeys successfully. The following are the results with Macaque monkeys:

• Vaccination one week before exposure to lethal levels of EBOV completely protected the monkeys against the EBOV-Makona.
  
• Vaccinating the monkeys three days before exposure afforded partial protection against EBOV.
  
• VSV-EBOV is likely to be equally protective against different strains of the Ebola virus.
  
• Animals vaccinated against EBOV showed the development of antibodies against the virus, which is considered crucial for developing immunity and exhibiting an adaptive response.
  

These preliminary results appear promising. The authors of the research article conclude, “Complete and partial protection was achieved with a single dose given as late as 7 and three days before challenge, respectively. This indicates that VSV-EBOV may protect humans against EBOV infections in West Africa with relatively short time to immunity, promoting its use for immediate public health responses.”

Written by Mangala Sarkar, Ph.D.

Primary References

Marzi, A., Robertson, S., Haddock, E., Feldmann, F., Hanley, P., Scott, D., . . . Feldmann, H. (2015). VSV-EBOV rapidly protects macaques against infection with the 2014/15 Ebola virus outbreak strain. Science. (n.d.). Retrieved August 8, 2015, from http://www.sciencemag.org/content/early/2015/08/05/science.aab3920.full

Media Availability: Single Dose Ebola Vaccine is Safe and Effective in Monkeys against Outbreak Strain. (n.d.). Retrieved August 8, 2015, from http://www.niaid.nih.gov/news/newsreleases/2015/Pages/VSV-EBOV.aspx

DoveMed Resources

Ebola Virus Disease (EVD). (n.d.). Retrieved August 8, 2015, from http://www.dovemed.com/ebola-virus-disease-evd/

Ebola Virus Can Reside in the Eyes Months After a Person is Declared Ebola-Free. (n.d.). Retrieved August 8, 2015, from http://www.dovemed.com/current-medical-news/ebola-virus-can-reside-eyes/

Additional References

Situation summaryData published on 07 August 2015. (n.d.). Retrieved August 10, 2015, from http://apps.who.int/gho/data/view.ebola-sitrep.ebola-summary-20150807?lang=en