A Ring Vaccination Trial in Guinea Halts Ebola’s Spread

In March 2015, public health teams in Guinea began testing an experimental vaccine known as rVSV-ZEBOV during the West African Ebola epidemic. Rather than attempting to vaccinate the entire population, researchers implemented a ring vaccination protocol. This strategy focused intervention on the direct contacts and contacts of contacts surrounding laboratory-confirmed patients. By immunizing the social network of family members, neighbors, and caretakers who visited dwellings or workplaces where patients spent time while symptomatic, epidemiologists aimed to create a protective barrier around each outbreak cluster.

The underlying vaccine was created by researchers at Canada's National Microbiology Laboratory in Winnipeg, under the Public Health Agency of Canada. The agency had patented the technology in 2003 and demonstrated its potential in animal trials funded by the Canadian and American governments between 2005 and 2009. The formulation used a live, attenuated vesicular stomatitis virus engineered to express the envelope glycoprotein of the Kikwit 1995 Zaire ebolavirus strain. In 2010, the Canadian agency licensed the intellectual property to Bioprotection Systems, a subsidiary of Newlink Genetics, for 205,000 dollars and modest royalties.