by Apoorva Mandavilli
The WHO on Wednesday endorsed the first ever vaccine to prevent malaria, debuting a tool that could save the lives of tens of thousands of children in Africa each year. Malaria is among the oldest known and deadliest of infectious diseases. It kills about half a million people each year, nearly all of them in sub-Saharan Africa — among them 2,60,000 kids under age 5.The new vaccine, made by GlaxoSmithKline, rouses a child’s immune system to thwart Plasmodium falciparum, the deadliest of five malaria pathogens and the most prevalent in Africa. The vaccine is not just a first for malaria — it is the first for any parasitic disease.
In clinical trials, the vaccine had an efficacy of about 50% against severe malaria in the first year, but dropped close to zero by the fourth year. And the trials did not measure the vaccine’s impact on preventing deaths, which has led some experts to question whether it is a worthwhile investment in countries with countless other intractable problems. But severe malaria accounts for up to half of malaria deaths and is considered “a reliable proximal indicator of mortality,” said Dr. Mary Hamel, who leads WHO’s malaria vaccine implementation program. “I do expect we will see that impact.”
A modelling study last year estimated that if the vaccine were rolled out to nations with the highest incidence of malaria, it could prevent 5.4 million cases and 23,000 deaths in kids younger than age 5 each year. To have a malaria vaccine that is safe, moderately effective and ready for distribution is “a historical event,” said Dr. Pedro Alonso, director of WHO’s global malaria programme. Parasites are much more complex than viruses or bacteria, and the quest for a malaria vaccine has been underway for a hundred years, he added.
Called Mosquirix, the new vaccine is given in three doses between ages 5 and 17 months, and a fourth dose roughly 18 months later. NYt news service