Advances in Vaccines for Marbug, Ebola Viruses

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ED GORDON, host:

This week, scientists announced they made progress in developing vaccines against Ebola and Marburg disease. The deadly Marburg virus, a so-called cousin of Ebola, is plaguing the Southern African nation of Angola. So far this spring, 433 Angolans have been infected, and more than 350 people have died. Right now, there's no cure and no way to prevent infection, except by quarantine. Researchers hope the vaccines will help fight the disease, especially in Africa. NEWS & NOTES' Farai Chideya spoke with NPR's health and science correspondent, Richard Knox, about how these diseases work.

FARAI CHIDEYA reporting:

So why do Ebola and Marburg inspire such fear, and what percent of those infected die?

RICHARD KNOX (NPR Health and Science Correspondent): Well, that's the first reason they're scary diseases, because a very high percentage of people who get infected with either one of these die, something like 80 to 90 percent. In Angola, this continuing epidemic, which seems to be winding down, has killed about 85 percent of the people who have gotten infected. And very few infections anywhere do that. People who die typically are doctors and nurses, and so that's--you know, that's scary obviously to the caregivers, but it's also scary to the communities to see the caregivers die.

Ebola, in particular--Marburg to a lesser degree, until recently--have had sort of mythic status. You know, they've been featured in a book called "The Hot Zone" by Richard Preston and the movie called "Outbreak" that sort of gave a horrific scenario of an outbreak in this country.

CHIDEYA: Now there are some viruses like the common cold that leave most people unharmed. This is obviously very, very different. Why has it been so hard to develop a vaccine for Ebola and Marburg, and what's the progress that's recently occurred?

KNOX: Well, there are a lot of factors as to why it's hard. First of all, the mysteriousness of these viruses--nobody really knows where they hide out and why they come out and what animals harbor them. And that makes it very hard to study them. Monkeys and other non-human primates are the best model to study. That means that, you know, scientists need to give diseases to animals and--to study them. And monkeys and primates are very scarce. They're very expensive. They cost thousands of dollars for each animal. You have to do this stuff in very high security labs and they're not many in the world, maybe just a handful, that can do this work. And the researchers have to wear, you know, head-to-toe moon suits and stuff so they don't get infected. And there really hasn't been much interest in doing this week until recently, because they were thought to affect only, you know, obscure countries in Africa. So, you know, they weren't a direct threat to us until bioterrorism issues came along. And scientifically, they're very difficult to work with because they kill so rapidly. Generally, vaccines are hard to make.

CHIDEYA: And so what's the breakthrough been with researchers recently that gives hope that there will be a vaccine.

KNOX: Well, a group of researchers in Canada and the United States just published a report in a journal called Nature Medicine that showed that they made a vaccine against--well, they made two vaccines, one against Ebola, one against Marburg. And when they put these vaccines into a group of monkeys and then infected them--or exposed them to the viruses, the vaccines were a 100 percent effective. None of the monkeys died, which is pretty impressive. And so they think that they're--you know, they're on the right track. There are a couple of other types of vaccines that have been sort of quietly worked on. So there's now, for the first time, some real prospect of being able to make a difference. It'll take a few years to get it to humans, though. These are hard things to work with. But, you know, if it's--it would really be exciting, it would really change things, if there were a vaccine for these really bad viruses.

CHIDEYA: NPR health and science correspondent Richard Knox, thanks for joining us.

KNOX: You're welcome.

CHIDEYA: Farai Chideya, NPR News.

GORDON: This is NPR News.

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