Ebola Vaccine Could Start Testing In Africa By January

Oct 21, 2014
Originally published on October 22, 2014 10:22 am

The World Health Organization says that efforts are on track to distribute an experimental Ebola vaccine in West Africa in January.

Two potential vaccines are now being tested for safety in people, and Russia is developing another one. While quantities will be limited, scientists say even a relatively small supply of vaccine can help bring the epidemic under control.

There's no guarantee that any vaccine will be effective, so it's good that several are in the pipeline. That includes an Ebola vaccine being developed by GlaxoSmithKline, which has already been tested in a small number of volunteers in the U.S., Europe and Africa.

Marie-Paule Kieny, assistant director-general for health systems and innovation at the World Health Organization, says a Canadian vaccine licensed to NewLink Genetics in Ames, Iowa, is now being tested in people as well, at the Walter Reed National Military Medical Center and the National Institutes of Health, near Washington, D.C.

Next month, those trials will be expanded to include several hundred volunteers in Europe. Those tests will involve 250 doses of each of these two front-running vaccine candidates, "and these data are absolutely crucial to allow decision-making on what dose level should go into the testing in Africa," Kieny says.

That's a critical question at the moment, because nobody now knows whether a tiny dose or a large dose would be required to protect someone from the Ebola virus. The largest dose in these tests will be nearly 1,000 times larger than the smallest dose.

"Everybody would like to have the lowest dose because, of course, you could have so much more vaccine than if it's the highest dose," Kieny says.

Health officials are hoping to have tens of thousands of doses available starting in January. But that could present a major manufacturing challenge, especially if each shot needed to contain a huge dose of the vaccine.

And while these two potential vaccines are the farthest along, they aren't alone. Three others are in earlier development stages at U.S. companies, and "some vaccines are also in development in Russia," Kieny told a WHO news conference in Geneva on Tuesday. "So we are in contact with Russians to see when they could be available for testing in Africa, and what type of doses, in terms of quantity, could be available in the months to come."

She says it's not clear whether the Russian scientists have already started safety testing in people.

Until quite recently, public health officials figured that a vaccine would come along too late to be of any use in controlling the current Ebola outbreak. But that attitude is changing.

"We could use a strategy similar to the ring vaccination strategy that was used in the smallpox eradication program," says Stephen Morse, an epidemiologist at Columbia University's Mailman School of Public Health.

The concept of ring vaccination is that you wouldn't need to immunize the many millions of residents in the affected West African countries. Instead, if health officials can see where the disease is heading next, they can focus on immunizing people who will soon be in harm's way.

That of course includes health care workers, who are at highest risk right now.

"That would not require large amounts of vaccine," Morse says, "but it probably would limit the spread of the epidemic considerably."

Using this strategy, the vaccine wouldn't have to be perfectly effective, and you wouldn't even need to vaccinate all people who are at risk in order to put brakes on the epidemic.

Drugs to treat Ebola would help as well.

Kieny says the French government plans to test a Japanese antiviral drug called Favipiravir in Guinea. And there's an international partnership coordinated by England's Oxford University to bring a half-dozen other potential drugs into the region as well.

She says the partnership is now visiting sites in the three African countries to identify which treatment centers would be adequate and would also be willing to participate in the testing of drugs.

Of course, public health officials responsible for stopping Ebola are still relying most heavily on the tried-and-true method: finding people who are sick and isolating them so the disease stops spreading.

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Transcript

ROBERT SIEGEL, HOST:

The World Health Organization says efforts are on track to distribute an experimental Ebola vaccine in West Africa in January. Two options are being tested for safety. Quantities will be limited, but even a relatively small supply of vaccine could help bring the epidemic under control, as NPR's Richard Harris reports.

RICHARD HARRIS, BYLINE: There's no guarantee that any vaccine will be effective so it's good that several are in the pipeline. That includes an Ebola vaccine being developed by GlaxoSmithKline, which has already been tested in a small number of volunteers in the U.S., Europe and Africa. World Health Organization official Marie-Paule Kieny says a Canadian vaccine, licensed to a small U.S. company, is now being tested in people, as well.

MARIE-PAUL KIENY: The first two tries, which are ongoing, are ongoing in the U.S. at Walter Reed, as well at NIH.

HARRIS: Next month, those trials will be expanded to several hundred volunteers in Europe. Those tests will include 250 doses of each of these two front-running vaccine candidates.

KIENY: And these data are absolutely crucial to allow decision-making on what dose level should go in the testing in Africa.

HARRIS: That's a critical question at the moment because nobody knows whether a tiny dose or a large dose would be required to protect someone from the Ebola virus. The largest dose in these tests would be nearly a thousand times larger than the smallest dose.

KIENY: Everybody would like to have the lowest dose to go forward because if it's the lowest dose then, of course, you can have so much more vaccine than if it's the highest dose.

HARRIS: Health officials are hoping to have tens of thousands of doses available starting in January. But that could present a major manufacturing challenge, especially if each shot needed a huge dose of the vaccine. Now while these two potential vaccines are the furthest along, they aren't alone. Dr. Kieny says three others are in earlier development stages at U.S. companies.

KIENY: Some vaccines are also in development in Russia. And so we are in contact with Russians to see when they could be available for testing in Africa and what type of doses, in terms of quantity, could be available in the months to come.

HARRIS: Until quite recently, public health officials figured that a vaccine would come along too late to be of any use in controlling the current Ebola outbreak. But that attitude is changing. Stephen Morse is an epidemiologist at Columbia University's Mailman School of Public Health.

STEPHEN MORSE: We could use a strategy, I think, similar to the ring vaccination strategy that was used in the smallpox eradication program.

HARRIS: The concept of ring vaccination is you shouldn't need to immunize the many millions of citizens in the affected West African countries. Instead, if health officials can see where the disease is heading next, they can immunize people who will soon be in harm's way. That, of course, includes health care workers who are at the highest risk right now.

MORSE: That would not require large amounts of vaccine, but probably would limit the spread of the epidemic considerably.

HARRIS: Using this strategy, the vaccine wouldn't have to be perfectly effective, and you wouldn't even need to vaccinate all people who are at risk in order to put the brakes on the epidemic. And drugs to treat Ebola would help as well. Dr. Kieny at the WHO said the French government is planning to test a Japanese antiviral drug called Favipiravir in Guinea. And there's an international partnership coordinated by Oxford University to bring a half a dozen other potential drugs into the region as well.

KIENY: The partnership is now visiting sites in the three African countries to identify which treatment centers would be adequate and would also be willing to participate in the testing of drugs.

HARRIS: Of course, public health officials responsible for stopping Ebola are still relying most heavily on the tried-and-true method, that is, find people who are sick and isolate them so the disease stops spreading. Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.