New vaccine hope in fight against ebola

An end to the ebola epidemic in West Africa may be in sight after results from a fast-tracked vaccine trial were described as “hugely important” and “very exciting” by experts.

The experimental vaccine VSV-ZEBOV was found to be 100% effective six days after it was administered to 7,651 people living in Guinea, where the virus has already claimed more than 2,500 lives.

It made no difference if people had the jab immediately or following a delay of three weeks after giving their consent to treatment.

Critically, non-vaccinated individuals were also protected. A “ring vaccination” strategy — used in the past to eradicate smallpox — was adopted to create a buffer zone of protection by reducing spread of the disease.

Commenting on the findings, published in The Lancet medical journal, Dr Jeremy Farrar, director of Britain’s biggest research charity the Wellcome Trust, said: “Our hope is that this vaccine will now help bring this epidemic to an end and be available for the inevitable future ebola epidemics.

“It should change how the world responds to emerging infectious disease threats.” The trial was given the title “ebola ca Suffit”, which means “ebola this is Enough”.

It took place in Basse-Guinea, the only district of Guinea with new ebola cases at the start of the study on April 1 this year.

For every newly-infected individual, researchers traced all the people he or she may have been in close contact with. Adult contacts aged 18 and older who were not pregnant or breastfeeding were offered the vaccine. If consent was given, adults were randomised either to receive it immediately or after a delay.

Comparisons between an active and “dummy” placebo vaccine could not be made for ethical reasons, since it would have meant condemning one group of participants to a high risk of death.

Under the ring vaccination strategy, vaccination was followed up by monitoring the contacts and contacts of contacts of an immunised individual.

Dr Marie Paule Kieny, one of the researchers from the World Health Organisation in Geneva, Switzerland, said: “Before the trial started, in most (population) clusters there had been a series of ebola cases over the weeks prior to randomisation. However, since the trial started, we have seen no new cases in vaccinated volunteers within 10 days of vaccination, regardless of whether vaccination was immediate or delayed.”

A total of 16 new cases were recorded in the “delayed” vaccination clusters, which included unvaccinated contacts.

Taking account of untreated as well as treated individuals, the vaccine provided 75% overall protection to communities participating in the trial.