The first Ebola vaccines will be shipped to West Africa Friday, loaded aboard a commercial flight from Brussels, Belgium, to Liberia.

Vaccine maker GlaxoSmithKline says it will eventually send 30,000 Ebola vaccines to Liberia for use in the first clinical trial testing in people who are at actual risk of catching Ebola – health care workers, close contacts of cases and perhaps burial workers as well.

“They’ve passed all the quality checks and now can be sent to the site,” Glaxo vice president Dr. Rip Ballou told NBC News. “We are also working on scaling up the production of the vaccine.”

“There will be another epidemic if there’s not a vaccine to prevent this."

On Thursday, the U.S. government announced the trial would be starting within the next two weeks. The National Institutes of Health helped develop the two vaccines that will be tested – one made by Okairos, a Swiss-Italian biotech company that Glaxo bought, and another one made by a collaboration of Canadian health experts, NewLink Genetics and licensed by Merck

“There will be another epidemic if there’s not a vaccine to prevent this,” Ballou said.

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Ebola has infected more than 21,000 people in Liberia, Sierra Leone and Guinea, and it's killed 8,600 of them. While the spread is slowing a little, the World Health Organization doesn't project an end to the epidemic before the middle of the year, and only then with a sustained effort.

“If we can come up with a vaccine that can be put into either a stockpile for emergency use or become a routine vaccine in these areas, I think this has a very big potential impact,” Ballou said.

“This is an unprecedented epidemic,” he added. “It is a highly populated part of Africa. It is an economically important part of Africa. If it were to spread into surrounding countries – think about Nigeria, the most populous nation in Africa.”

The enthusiasm for making the vaccines hasn’t always been there. Ebola vaccines have been in the works for years, but because there was no real pressure to get them made, funding was thin and work agonizingly slow. With the epidemic in West Africa, there’s been a renewed infusion of cash, interest and support for the work – and big drugmakers like Glaxo and Merck have jumped into the mix.

Health regulators have also put their approvals into the fast lane. The two vaccines that will be tested in Liberia and, later, in Sierra Leone, are jumping straight into the final phase of testing. New drugs and vaccines go through a multi-step testing process – after they’ve been shown to be safe and effective in animals. They usually must pass three phases of human testing: Phase 1 trials in a very small number of people to show they are safe; Phase 2 trials to check safety in more people and to start to look to see what dose might be effective; and then Phase 3 trials to truly show whether the new product is effective.

“I don’t think anybody would prefer to see it done this way."

These vaccines are jumping straight from Phase 1 trials among volunteers in the U.S. and Europe to Phase 3 trials among people at true risk in West Africa.

“I don’t think anybody would prefer to see it done this way. There are many, many things we would prefer to have much more information about,” Ballou said.

“This is a very serious emergency and we are doing everything we can to respond to it while being fully responsible for the actions that we take.”

The vaccine makers and the groups that will distribute and administer the vaccines face big challenges even if they are shown to protect people. The vaccines both use live viruses – not Ebola, but carrier viruses with tiny, harmless pieces of Ebola attached. They must be kept frozen at very cold temperatures, far colder than most freezers can manage.

“We have to tweak the formula to make them more stable,” Ballou said. That takes more testing. “It takes months and months to be able to generate data,” he added.