Scientists use old vaccination method to beat new viruses

Using a vaccination method first established in the fight against smallpox, researchers now claim their experimental vaccine for Ebola virus results in 100% efficacy. This strategy may have importance not only for Ebola virus but other deadly viruses including the recent Zika virus outbreak.

The findings, based on early results of a study published in The Lancet in July, were discussed at the American Association for the Advancement of Science meeting this month.

Dr. Ana Maria Henao Restrepo, who is a medical officer for the World Health Organization and lead author of the study, worked closely with Ira Longini, a biostatistics professor from the University of Florida.

They employed the "ring vaccination" method, which was used to eradicate smallpox in the 1970s. It involves vaccinating people who have had contact with people who contracted Ebola and the close contacts of people who had that contact.

The earlier study included 7,651 people, some 3,500 of whom were vaccinated with an experimental Ebola vaccine. They found that 100% of the people vaccinated with the Ebola vaccine were protected from contracting the illness. In rings where half the number of people were vaccinated, there was 75% effectiveness in reducing the risk of Ebola illness.

"This type of analysis is a very robust design," Longini said in a release. "It worked for the Ebola vaccine, and could work for the Zika vaccine, or any other emerging threat we might see. Now, we want to make the point that we can almost certainly contain future Ebola outbreaks, and that we will probably have a new paradigm and tool for dealing with new outbreaks of whatever emerges in the future."

Their next step is to publish their more recent clinical trials done on ring vaccinations of new clusters of Ebola, including one cluster in Sierra Leone--a country that has been badly affected by the virus outbreak. They will also study how long a vaccinated person's immunity to Ebola lasts.

- here's the release