Still Looking for Malaria Vaccine, 10 Years Later
MADELEINE BRAND, host:
This is DAY TO DAY. I'm Madeleine Brand.
Scientists often seem to be on the verge of a great discovery. Take the search for a vaccine against malaria. More than a million children die each year from the parasitic infection, so a vaccine is urgently needed.
NPR's Joe Palca has been revisiting stories he reported a decade or more ago. Today, Joe looks back at a time when a malaria vaccine seemed almost within reach.
JOE PALCA reporting:
In 1994, I reported on the vaccine SPf66. It wasn't intended to prevent people from getting malaria. Instead, the idea was to keep them from suffering the most deadly effects of the disease. As part of my reporting, I went to the Gambia, where doctors were testing the vaccine.
(Soundbite of a crying child)
PALCA: Malaria researchers are ecstatic that for the first time there's something they can do to prevent malaria. In tests just completed in East Africa, the genetically engineered vaccine reduced the number of cases of malaria by about 30 percent in children under five. Here in the Gambia the idea is to see if the vaccine is effective in even younger children, children under a year old. If it is, it could be given with vaccines against other childhood diseases, saving millions of lives.
In fact, scientists hoped they were on the verge of one of the most significant breakthroughs of our time. Here's D.A. Henderson, a senior official at the U.S. Department of Health in 1994.
Mr. D.A. HENDERSON (United States Department of Health): We've not had a vaccine at all against any parasitic infection. And to have one against a disease as severe as malaria represents a major step forward. To have a vaccine against malaria would be as - virtually as significant a development as against AIDS.
PALCA: So where is SPf66 today, when it seemed such a promising vaccine 12 years ago?
Mr. LEE HALL (National Institute of Allergy and Infectious Diseases): What happened over time, the vaccine efficacy drifted down. In many cases, the efficacy was zero or below.
PALCA: In other words, says Lee Hall, it wasn't working. Hall is chief of the parasitology branch at the National Institute of Allergy and Infectious Diseases.
Mr. HALL: Early on there were some very promising result. And in fact the first paper that came out in 1992 suggested a potential efficacy of 80 percent.
PALCA: Hall says that after their initial successes, scientists did what they normally do when they produce promising results: they tried to do it again. And as often happens, when it was tested on more people, under more rigorous conditions with more careful controls, initial promising results just evaporated. But Hall says despite the failure of SPf66, scientists learned a lot from the experience. And when new candidate vaccines are ready to be tested scientists will be better prepared.
Mr. HALL: This was the first time that a malaria vaccine had been actually taken into the field and tested. They really became much more sophisticated and aware of the difficulties of testing malaria vaccines in the field.
PALCA: Hall says that alone was a significant contribution to the intellectual and scientific basis of malaria vaccine development. And many of the same scientists who worked on SPf66 are currently testing new vaccines. Today there are still hundreds of millions of people around the world infected with malaria.
Would you say that a vaccine against malaria would be as significant a development as a vaccine against AIDS?
Mr. HALL: I think it's on the same level, yes.
PALCA: But for now that development still seems quite a ways off.
Joe Palca, NPR News.