LETHAL DISEASE Malaria vaccine proves effective, scientists report

A vaccine offers the greatest potential for controlling the parasitic disease.
LOS ANGELES TIMES
After more than two decades of study, researchers said Thursday that they have found the first vaccine that is effective against malaria. Trials in Africa showed that the vaccine blocked almost half of new infections in young children and reduced serious disease by nearly 60 percent.
Experts termed the results a major breakthrough in efforts to tame a disease that afflicts 400 million people each year, killing 1 million to 3 million -- most of them children in Africa. Malaria is the leading killer of children under age 5 and ranks with AIDS and tuberculosis on the list of the world's most lethal diseases.
Researchers are not sure how long the vaccine's protection will persist, but even a partially effective vaccine will have great value in fighting a disease that is becoming increasingly resistant to the drugs most commonly used to treat it.
More tests to come
More trials are needed to confirm the vaccine's efficacy, particularly in the youngest children, who are most likely to die from infections. But it could be available for widespread use by 2010, experts said.
By that time, the World Health Organization predicts, half the world's population will be living in areas of high exposure to the disease, compared with 41 percent now.
Other potential malaria vaccines have been tested, "but we have never seen results like this before," said Dr. Pedro Alonso of the University of Barcelona, who headed the trial reported in this week's edition of the journal Lancet.
An urgent goal
Producing a malaria vaccine is considered the most urgent goal in controlling the disease, because it offers the safest, least expensive method. Antimalarial drugs such as Larium, known generically as mefloquine, can be used to prevent infection by killing the parasite, but they are much more expensive, require regular use and can produce many undesirable side effects.
It's a parasite
Developing a malaria vaccine has been difficult because the disease is produced by a parasite with a complicated life cycle. Science has yet to come up with an effective vaccine against a parasite, said Melinda Moree, director of the Malaria Vaccine Initiative.
Malaria is caused by four closely related parasite strains, the most common and deadly of which is Plasmodium falciparum. The strains thrive in Anopheles mosquitoes.