Malaria vaccine is a letdown but could still reduce numbers of cases
The world’s leading malaria vaccine candidate appears to be a disappointment, with final study results showing it doesn’t work very well and that initial protection fades over time.
Despite the dismal results — it protects about one-third of children vaccinated — developers are moving ahead to get it approved because it could still help protect some children from getting the mosquito-spread disease.
GlaxoSmithKline has spent hundreds of millions of dollars on the vaccine, which is likely to be the world’s first licensed shot for malaria. A decision from the European Medicines Agency is expected later this year.
The World Health Organization had previously set a target of 2015 for having a malaria vaccine that was at least 50 percent effective with protection lasting longer than a year. According to a study published Friday in the journal The Lancet, those goals have been missed with the GlaxoSmithKline vaccine, though scientists say the shot isn’t a complete waste.
“Everyone accepts that this is not the perfect or the last malaria vaccine,” said Brian Greenwood of the London School of Hygiene and Tropical Medicine, the study’s lead author. “It’s not good enough to stop transmission but it will cut the huge burden of disease.”
He noted there are about 200 million cases of malaria every year, with many children infected multiple times.
“Preventing some of those attacks is not insignificant,” he said. The vaccine study involved about 15,500 babies and toddlers in Africa; one group got three doses; a second group also got a booster shot and a third group got dummy shots. All of the children used a mosquito bed net and they were followed for up to four years.
Overall, the vaccine was about 30 percent effective in those who got three doses and a booster shot but the protection waned over time.
It worked a little better — about 36 percent — in those 5 months to 17 months. But it was only 26 percent effective in babies and vac- cination made no difference in the rates of severe malaria or deaths.
More commonly used vaccines, like those for measles and polio, work more than 90 percent of the time.
Researchers reported side effects including pain, fever and convulsions. There were also 22 cases of meningitis in babies and toddlers who were immunized compared to one case in the group that didn’t, but the researchers couldn’t explain why.
Greenwood said the vaccine would likely be made available at cost and that major funders have already expressed interest in paying for immunization campaigns. Other experimental malaria vaccines are being developed but are at least several years behind.
WHO estimates malaria killed more than 580,000 people in 2013, mostly children in Africa under age 5. Officials mostly try to slow the mosquito-spread disease using bed nets, insecticide spraying, and giving out malaria medications to entire villages in areas with high levels of the disease.