Ebola vaccine?

PharmaLive: Single-shot Outbreak Vaccine Provides Full Protection Against Ebola According to Results of New Animal Studies: "Dutch biotechnology company Crucell N.V. (Euronext, Nasdaq: CRXL) today reported new results from its Ebola vaccine studies. The studies, conducted together with the Vaccine Research Center (VRC) of the US National Institutes of Health (NIH) and the US Army Research Institute of Infectious Diseases (USAMRIID), confirm previously published results showing that a single shot of the vaccine protected monkeys completely against a lethal Ebola challenge. "

This is great news - a major step down the road to developing an Ebola vaccine for people. A vaccine would be a critical tool in stopping outbreaks, particularly by vaccinating health care workers and high-risk contacts during an outbreak. The ongoing Marburg outbreak in Angola shows the risk to health care workers during an outbreak is very high. Losing health care workers during an outbreak further exacerbates transmission, and makes it more difficult to contain.

Ebola can also have devastating effects on great ape populations. Now that there is progress towards a vaccine, there will be calls, as there have in the past, to vaccinate gorillas during outbreaks. If a vaccine is developed, the trick would be to get it into a form that makes mass vaccination of gorillas feasible - they just aren't going to line up for a shot, and they are picky eaters unlikely to eat baits randomly distributed on the ground.

The issue highlights the two main hypotheses of Ebola transmission in gorillas. Are outbreaks maintained by gorilla-to-gorilla transmission, or are the outbreaks maintained by continued introduction from some other animal reservoir like bats or insects. If gorilla-gorilla transmission is the main route, then ring vaccination around affected areas might stop an outbreak. However, if transmission is mainly from some highly mobile reservoir species to gorillas, then its unlikely that enough gorillas could be vaccinated to stop an outbreak ... which ones would you vaccinate?

The great ape connection is key: recent research has shown that the recent outbreaks of Ebola can be traced to consumption of wildlife (mainly apes but other species as well: Wild Animal Mortality Monitoring and Human Ebola Outbreaks, Gabon and Republic of Congo, 2001–2003,)

Some basic questions need to be answered about the epidemiology of Ebola. What is the reservoir? What precipitates outbreaks in the reservoir, then in wild mammals like apes? Research is ongoing.