Health

Experimental Ebola vaccine passes early safety test

GlaxoSmithKline’s new vaccine also yields encouraging results for immune response

An Ebola patient arriving at Geneva University Hospital HUG in Geneva, Switzerland on November 21st. Early safety trials for a new vaccine to combat the deadly disease have had encouraging results. Photograph: EPA/Julien Gregorio

Thu Nov 27 2014 - 08:01

An experimental Ebola vaccine caused no serious side effects and produced an immune response in all 20 healthy volunteers who received it in an early-stage clinical trial, according to a report in the New England Journal of Medicine on Wednesday.

The vaccine is being developed by GlaxoSmithKline and the trial is being conducted in the US in Bethesda, Maryland. It began on September 2nd and will monitor the volunteers for 48 weeks.

Scientists say the trial is primarily aimed at assessing how safe the vaccine is, but the immune response offered hope that it would also be effective.

"The safety profile is encouraging, as is the finding that the higher dose of vaccine induced an immune response quite comparable to that which has completely protected (lab) animals from Ebola," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID).

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The vaccine was developed at NIAID and Okairos, a biotechnology company acquired by GlaxoSmithKline.

It contains genetic material from two Ebola strains - Zaire, responsible for the current outbreak in West Africa, and Sudan - but no virus, so it cannot cause the disease.

Anti-Ebola antibodies

Because it is unethical to expose volunteers to Ebola, researchers assess the effectiveness of the treatment by whether they trigger production of anti-Ebola antibodies and immune-system T cells.

The trial enrolled volunteers ages 18 to 50. Half received a lower dose and half a higher dose. All 20 developed anti-Ebola antibodies within four weeks, with those on the higher dose producing more.

The size of the dose also affected production of T cells. Seven of 10 people on the high dose produced one crucial kind of T cell, but only two on the low dose did.

The higher the dose required to trigger immunity, the more challenging and expensive it will be to produce large quantities of vaccine, manufacturers say.

Dr. Daniel Bausch of Tulane University called the results promising, but said there are many more challenges ahead before the safety and effectiveness of the vaccine can be guaranteed.

Another GlaxoSmithKline vaccine, against the Zaire strain, is undergoing safety trials in England, Mali and Switzerland, while one from Iowa-based NewLink Genetics is being tested in Maryland.

A trial of an Ebola vaccine from Johnson & Johnson is also scheduled to start in January.

Reuters

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