Experimental Malaria Vaccine Blocks The Bad Guy's Exit : Shots - Health News Most attempts at a malaria vaccine have unsuccessfully tried to keep the parasite from breaking into red blood cells. But a new twist that keeps the parasite from escaping the cells may work better.

Experimental Malaria Vaccine Blocks The Bad Guy's Exit

  • Download
  • <iframe src="https://www.npr.org/player/embed/314884348/314925157" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript


From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.


And I'm Audie Cornish.

This next story is about a disease that is a major killer of children - malaria. But it's also a story about how a fresh idea can inject new energy into the effort to prevent a devastating disease.

NPR's Richard Harris weaves these two threads together.

RICHARD HARRIS, BYLINE: Malaria is caused by a parasite that mosquitoes spread with a bite. This disease causes a lot of death and disability, especially in Africa, and researchers have been working on a vaccine to prevent it for a long, long time. Jonathan Kurtis at Rhode Island Hospital and Brown University says there has been success, of a sort.

DR. JONATHAN KURTIS: For the past 40 years, we've had wonderful vaccines for malaria. No rodent need live in fear. They've been great at protecting mice.

HARRIS: Unfortunately, even the best of these vaccines has been only so-so at protecting people. We aren't simply giant mice, after all.

KURTIS: And so instead of starting with mice, we actually began with humans.

HARRIS: In fact, he started his research with children. Kids are most vulnerable to malaria, so Kurtis figured he could find new clues for a malaria vaccine by studying toddlers who'd been infected with the malaria parasite but who didn't get sick.

His colleagues at the National Institutes of Health had painstakingly collected blood samples from children in east Africa. And Kurtis studied those samples to look for small pieces, proteins in the malaria parasite that might be its Achilles' heel.

KURTIS: We're finding the rare needle in a haystack. We're finding the rare parasite protein that generates a protective immune response.

HARRIS: Vaccines direct the immune system to attack an invader. Earlier vaccines have targeted proteins on the malaria parasite that help it break into red blood cells, where it reproduces.

KURTIS: Blocking invasion of red cells is a daunting task and it's daunting because the parasite is only outside the red cell for about 15 seconds.

HARRIS: Before it invades another red cell. But the protein that Kurtis found on the parasite wasn't part of that invasion pathway.

KURTIS: Our parasite protein is critical for the parasite's escape from the red cell. And it needs to escape from the red cell if it's going to go on and infect other red cells and multiply.

HARRIS: Kurtis looked at children who had gotten infected with the malaria parasite but who didn't get seriously ill. And he discovered that their young immune systems had produced antibodies that attack this escape protein. These lucky children...

KURTIS: Had zero cases - zero cases of severe malaria - which was sort of astonishing, actually.

HARRIS: Kurtis and his colleagues report this result in the latest Science magazine. But this is really the beginning of the story.

DYANN WIRTH: This is a long way from a vaccine that could be used in humans.

HARRIS: Dyann Wirth is a malaria vaccine researcher at the Harvard School of Public Health.

WIRTH: But I do think this addresses what I feel is one of the problems with the current malaria vaccine approach. And that is the field seems to be focused on molecules that were discovered decades ago.

HARRIS: This really is a fresh idea, she says, championed by a scientist who is not personally invested in those well-known molecules. Since even the best of those is only partially effective, the field could really use some new ideas. Though most discoveries don't pan out, science can advance rapidly when something new does work.

For his part, Jonathan Kurtis isn't promising that his discovery will be the be-all-and-end-all for malaria prevention.

KURTIS: It would be ludicrously fortuitous to think that this would be a standalone vaccine.

HARRIS: But if it works even partially, it could eventually be used in combination with other malaria vaccines to deliver a one-two punch against the parasite.

There's a lot more testing to do. The potential vaccine will be tried in monkeys and if it looks promising there, Kurtis can start the long and challenging process of testing it out in people.

Richard Harris, NPR News.

Copyright © 2014 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.