Although Ebola has no known cure, scientists and pharmaceutical companies around the world are working to develop a vaccine against the virus.
Two potential vaccines in development at drug company GlaxoSmithKline and the Public Health Agency of Canada already are undergoing human clinical trials in the U.S., Europe and some countries in Africa. By January 2015, the World Health Organization says human clinical trials could be underway in West Africa.
Right now, doctors care for Ebola patients by keeping them hydrated, maintaining their blood pressure, treating infections as they occur and replacing lost blood. But a vaccine could help end this outbreak and prevent future ones. What challenges must be overcome?
Clinical trials usually take years. Because of the extreme need for an Ebola vaccine, and because initial tests reveal no harmful effects in humans, scientists are streamlining their trials. There will be three phases of successively larger sample sizes, but the World Health Organization will begin secondary and tertiary testing phases immediately after the primary phase, without waiting for preliminary results. If trials continue to go well, pharmaceutical companies will aim to have millions of doses ready by the beginning of 2015.
Is it fair to give some potential Ebola victims a placebo? When trials begin in West Africa, some people will receive a placebo even though all are at risk. This is because the most reliable way to judge the vaccine’s effectiveness is through a randomized controlled trial, in which a control group receives a placebo and an experimental group receives the vaccine. Some health experts recommend an alternate “step wedge” method, in which people are vaccinated sequentially and every participant eventually receives a dose of the vaccine.
How can doses be distributed in areas lacking sufficient electricity to refrigerate the vaccine? In some African countries, mobile towers have been used for electricity to keep vaccines refrigerated. Experts are exploring this and other solutions.