Experimental Ebola Vaccine Raises Hopes

The worst Ebola outbreak since 2014, when the deadly virus killed more than 11,000 people in western Africa, is erupting in the Democratic Republic of Congo. By mid-May 2018, the outbreak proved deadly for 27 people and affected dozens more as the virus made its way from a sparsely populated rural region to Mbandaka, a city of more than 1 million. And, on May 24, two Ebola-infected patients fled a Mbandaka treatment facility, fueling fears the virus — it kills about half the people it infects — could continue to spread.

As of May 29, 2018, the World Health Organization still refrained from calling the outbreak a global health emergency, but it did begin transporting an experimental Ebola vaccine known as rVSV-ZEBOV to the region, in an attempt to corral the spread of the virus. Although this Ebola vaccine is still under testing before it gains final approval, it already has been used during an earlier outbreak. In the 2014 West Africa Ebola epidemic, the vaccine was administered and proved effective in slowing the virus' spread.

To create the vaccine, researchers at the Canadian Public Health Agency and the U.S. Army Medical Research Institute replaced a gene in a virus that causes vesicular stomatitis with a gene from Ebola. Vesicular stomatitis is a virus in the same disease family that includes rabies, and in animals, causes excessive saliva, mouth sores and lameness. Unless a secondary infection sets in, most animals recover on their own in about two weeks.

More than 7,500 doses of the Ebola vaccine are expected to be given to people showing symptoms in the affected Congo regions — as long as the refrigeration chain for the vaccines remains unbroken. To add to the level of difficulty in combating the spread of Ebola, the vaccine requires continual cool temperatures to remain active. This means transporting it in containers cooled by liquid nitrogen over rough terrain in hot weather. It's yet another obstacle in this go-round of the virus, one that is especially troubling because it has moved to a highly populated area. Previously, there have been several Ebola outbreaks in the Congo that were contained because they occurred in remote areas.