Experimental Ebola vaccines
WHO consultation on Ebola vaccines
From 29–30 September, WHO organized an expert consultation to assess the status of work to test and eventually license two candidate Ebola vaccines. More than 70 experts, including many from affected and neighbouring countries in West Africa, attended the event.
The expertise represented among participants ranged from the virology of emerging infections, to regulatory requirements that must be met, to medical ethics, public health, and infectious diseases. Heads of clinical research and other executives from the pharmaceutical industry also presented their views.
Some participants came with more than 3 decades of experience working in Africa on other infectious diseases.
Experts on the use of innovative, cutting-edge trial designs also shared their most recent work.
The overarching objective was to take stock of the many efforts currently under way to rapidly evaluate Ebola vaccines for safety and efficacy. The next step is to make these vaccines available as soon as possible – and in sufficient quantities – to protect critical frontline workers and to make a difference in the epidemic’s future evolution.
All agreed on the ultimate goal: to have a fully tested and licensed product that can be scaled up for use in mass vaccination campaigns.
Two promising candidate vaccines
Given the public health need for safe and effective Ebola interventions, WHO regards the expedited evaluation of all Ebola vaccines with clinical grade material as a high priority.
Two candidate vaccines have clinical-grade vials available for phase 1 pre-licensure clinical trials.
One (cAd3-ZEBOV) has been developed by GlaxoSmithKline in collaboration with the US National Institute of Allergy and Infectious Diseases. It uses a chimpanzee-derived adenovirus vector with an Ebola virus gene inserted.
The second (rVSV-ZEBOV) was developed by the Public Health Agency of Canada in Winnipeg. The license for commercialization of the Canadian vaccine is held by an American company, the NewLink Genetics company, located in Ames, Iowa. The vaccine uses an attenuated or weakened vesicular stomatitis virus, a pathogen found in livestock; one of its genes has been replaced by an Ebola virus gene.