Ebola vaccine “extremely promising” in clinical trial–WHO

Results from a phase-III trial of the vaccine candidate VSV-EBOV has shown the vaccine is highly effective against Ebola, the World Health Organisation has said. It said results from a preliminary trial in Guinea showed “an extremely promising development,” according to Dr Margaret Chan, WHO director-general. “The credit goes to the Guinean Government, the people […]

Results from a phase-III trial of the vaccine candidate VSV-EBOV has shown the vaccine is highly effective against Ebola, the World Health Organisation has said.

It said results from a preliminary trial in Guinea showed “an extremely promising development,” according to Dr Margaret Chan, WHO director-general.

“The credit goes to the Guinean Government, the people living in the communities and our partners in this project. An effective vaccine will be another very important tool for both current and future Ebola outbreaks.”

While the vaccine up to now shows 100% efficacy in individuals, more conclusive evidence is needed on its capacity to protect populations through what is called “herd immunity”.

Guinean authorities have approved the continuation of the trial.

“This is Guinea’s gift to West Africa and the world,” said Dr Sakoba Keita, Guinea’s national coordinator for the Ebola response.

Researchers found a protein in hose and cattle virus similar to the surface protein of Zaire strain of Ebola virus.

The protein is smuggled into a person’s body in a vesicular stomatis virus (VSV). It does not cause human illness but it activates the immune system and teaches the body to recognise and react to Ebola protein and be able to fight Ebola when it arrives in a vaccinated person.

The virus has infected more than 27,000 people since it broke out in West Africa and killed more than 11,000 in most-affected countries.

More than 7,000 people volunteered for the vaccine trial, researchers reported in the journal Lancet.

They used a “ring” vaccination method—vaccinating people immediately in contact with an infected person to create a protective “ring” and stop the virus from spreading further, said John-Arne Røttingen, Director of the Division of Infectious Disease Control at the Norwegian Institute of Public Health and Chair of the Study Steering Group.

The same vaccination method was used to eradicate smallpox.

Half of the rings were vaccinated three weeks after an infected patient was identified to provide a term of comparison with rings that were vaccinated immediately.

“This now stops,” the WHO said. “In addition, the trial will now include 13 to 17-year-old and possibly 6 to 12-year-old children on the basis of new evidence of the vaccine’s safety.”

“In parallel with the ring vaccination, we are also conducting a trial of the same vaccine on frontline workers,” said Bertrand Draguez, Medical Director at Médecins sans Frontières.

“These people have worked tirelessly and put their lives at risk every day to take care of sick people. If the vaccine is effective, then we are already protecting them from the virus. With such high efficacy, all affected countries should immediately start and multiply ring vaccinations to break chains of transmission and vaccinate all frontline workers to protect them.”

The vaccine was developed by the Public Health Agency of Canada.

“This is a remarkable result which shows the power of equitable international partnerships and flexibility,” said Jeremy Farrar, Director of the Wellcome Trust, one of the funders of the trial.