Preliminary data from Phase I clinical trials of two Ebola vaccines ̶ ChAd3-ZEBOV vaccine, being developed by GlaxoSmithKline, and rVSV-ZEBOV vaccine, being developed by NewLink Genetics and Merck Vaccines USA ̶ presented to a gathering of government officials, vaccine manufacturers, research institutions and international partners at WHO’s headquarters in Geneva on 8 January, showed encouraging results.

Produced by the National Institute of Allergy and Infectious Diseases (NIAID), under a very-high magnification, this digitally-colorized scanning electron micrograph (SEM) depicts a single filamentous Ebola virus particle that had budded from the surface of a VERO cell of the African green monkey kidney epithelial cell line.
Produced by the National Institute of Allergy and Infectious Diseases (NIAID), under a very-high magnification, this digitally-colorized scanning electron micrograph (SEM) depicts a single filamentous Ebola virus particle that had budded from the surface of a VERO cell of the African green monkey kidney epithelial cell line.

Participants at the meeting also heard details of the development of vaccines by Johnson & Johnson, in association with Bavarian Nordic, for which the first Phase I trial began in January. Additional vaccines are being developed by other companies and organizations including the biotech company Novavax and the Russian Federal Ministry of Health.

Phase II trials of the rVSV-ZEBOV vaccine are expected to start in several countries in Cameroon, Ghana, Mali, Nigeria and Senegal in February 2015. These trials will test for safety and capacity to induce an immune response in larger numbers and in broader populations, including the elderly, children and persons living with HIV.

Phase III trials are also planned to start in early 2015, in Guinea, Liberia and Sierra Leone, the three countries most affected by Ebola. The objectives of these trials will be to assess whether the vaccines protect against Ebola virus disease and to further document safety.