Ebola vaccine shows promise in primates

Successful tests of a vaccine for the Ebola virus in primates has scientists hoping to adapt the treatment for humans.

"We are seeing more and more naturally occurring human outbreaks of this deadly disease. With worldwide air travel and tourism, the virus can now be transported to and from remote regions of the world. And it has huge potential as a possible weapon of bioterrorism," Dr. Anthony Sanchez, from the Centers for Disease Control in Atlanta, said in a release. "We desperately need a protective vaccine."

Dr. Sanchez is presenting an overview on Monday of the Ebola vaccine's development at the Society for General Microbiology's meeting in Edinburgh, Scotland.

There have been more than 1,500 reported cases of Ebola haemorrhagic fever in humans.

Last year, Canadian scientists heralded an experimental Ebola vaccine developed in Winnipeg that could eventually become the first treatment for people newly infected with the deadly virus.

Testing in three types of animals showed the vaccine kept at least half from dying when it was administered after infection, Canadian and American researchers reported in a January 2007 issue of the journal Public Library of Science Pathogens.

Most promising was the fact that four of eight primates injected with a lethal dose of Ebola virus survived when they were given the vaccine within 30 minutes of exposure.

Last year's study marked the first time a vaccine against one of the species of Ebola viruses had been shown to be effective in what's called a post-exposure setting. In fact, it's the first time anything has been shown to improve survival after infection with an Ebola virus.

Most vaccines are given to prevent illness. But a few, like those for smallpox and rabies, are used after infection to help the immune system fight off the invading pathogen. In the case of infection with filoviruses like Ebola, Marburg and Lassa fever, that help is crucial because the viruses act by first suppressing the immune response.

Ebola starts abruptly and symptoms include fever, headache, sore throat, weakness, joint and muscle aches, diarrhoea, vomiting and stomach pain. A rash, red eyes and bleeding may also occur. About 90 per cent of people and non-human primates who catch the illness die.

Because the Ebola virus is so dangerous, producing and testing a vaccine is an extremely challenging and slow process — a small number of high containment facilities exist with staff capable of doing the testing.