A U.S. health agency is speeding up clinical trials of a possible vaccine against the deadly Ebola virus that so far has killed more than 1,500 people in West Africa.

If successful, the next step would be a larger trial in countries where the outbreak is occurring.

According to Dr. Anthony Fauci, who will oversee the trials at the National Institutes of Health, the anti-Ebola vaccine that protects monkeys from the deadly virus has been slated for human trials early because of the dire situation in West Africa.

"You want to balance the need to get a potentially effective vaccine to the people who need it as quickly as possible, at the same time that you structure it in a way that you can get some meaningful information as to whether it does work or not, and whether it does harm," he said, emphasizing the critical emphasis on safety.

"We’ve had experience with vaccines that you actually think are going to prevent infection and they make things worse."

If the initial lab trials go well, the next step would be a larger trial in countries where the outbreak is occurring, a complex scientific trial that entails monitoring those given the vaccine.

According to Fauci, the field vaccine trials are very different from providing experimental drugs to treat Ebola.

"It’s not like a drug in which you are giving it to a very sick person who has no other option," he said. "A vaccine is given to a healthy person, so the idea that ‘first do no harm' is much, much more compelling when you are dealing with someone who is a normal healthy person versus someone who is desperately ill and has no form of therapy but needs something."

One of the biggest concerns is the lack of infrastructure in countries where the outbreak is raging: too few doctors, too little protective gear, not enough treatment centers or medicines to help sick patients. The World Health Organization is asking for half a billion dollars to address these issues.

If a larger trial is warranted, it will start early next year. Fauci says he hopes the situation in West Africa will be better under control by then. Still, he says even if the vaccine is effective, it's not the answer to the current outbreak.

“We have an ongoing epidemic," he said. "We do not have a vaccine, so that’s a hypothetical. We do not have drugs, so that’s a hypothetical. Right now, what we do have is the possibility of infection control, isolation, quarantine and contact tracing. That is what is going to bring this epidemic under control."

In the meantime, health officials say precaution and prevention remain the best defense against the disease.