Potential Ebola vaccine passes first human tests

 

WASHINGTON (AP) -- The first vaccine designed to prevent infection with the lethal Ebola virus has passed initial safety tests in humans and has shown promising signs that it may protect people from contracting the disease, government scientists reported Friday.

 

Just 21 people received the experimental vaccine in the early stage testing. Much more research is necessary to prove whether the vaccine will prove successful, cautioned lead researcher Dr. Gary Nabel of the National Institutes of Health.

Still, the results are encouraging for U.S. scientists who worry not only that the horrific virus might be used as a terror weapon but note that natural outbreaks in Africa seem to be on the rise.

Ebola hemorrhagic fever kills within days by causing massive internal bleeding. There is no cure. Ebola is highly contagious, and up to 90 percent of people who catch it die.

 

The virus was identified in 1976, and scientists still don't know where it incubates between outbreaks. So far they have occurred only in Africa, apparently when people come into contact with infected apes or bushmeat, the meat of ape, which is eaten in many areas of Africa.

A vaccine would be useful not only to quell a bad outbreak, but as advance protection for doctors, nurses and animal-care workers.

 

Nabel and colleagues at the NIH's Vaccine Research Center developed a vaccine made of DNA strands that encode three Ebola proteins. They boosted that vaccine with a weakened cold-related virus, and the combination protected monkeys exposed to Ebola.

The first human testing looked just at the vaccine's DNA portion; the full combination will be tested later.

 

At a microbiology meeting in Washington on Friday, Nabel and colleagues reported seeing no

worrisome side effects when comparing six people given dummy shots with 21 volunteers given increasing doses of the DNA vaccine.

Moreover, the vaccine recipients produced Ebola-specific antibodies, giving "us some confidence that the vaccine is having an effect on the immune system," Nabel said.

Once the complete vaccine has passed additional safety testing, the question is how to prove that it will protect people. NIH plans to test whether people have the same immune-system reactions to the vaccine as do monkeys that are protected by it.