A new global estimate of malaria deaths by researchers in Seattle has revealed the death toll is much greater than most experts had thought -- and is not, as had been universally assumed, mostly a killer of children.
The study found more than 1.2 million people died from malaria in 2010, nearly twice the official estimate put out by the World Health Organization, and more than a third of the deaths were in adults.
The common wisdom has been that 99 percent of malaria deaths are in young children because adults develop immunity.
"This radically changes the picture," said Dr. Christopher Murray, lead author of the study and director of the University of Washington's Institute for Health Metrics and Evaluation (IHME).
The findings, which will likely shock many in the global health community, are published in The Lancet.
The war is being won, but needs more ammo
Despite the finding that the death toll overall from malaria is much higher than the conventional wisdom, the study did show that the billions of dollars spent over the last decade or so to distribute bed nets, drugs and for other efforts in the massive international effort to reduce malaria is still succeeding.
"We actually showed a greater decline in deaths overall than many had assumed," Murray said.
The study used a different and more sophisticated analytical strategy guiding a much bigger research initiative soon to be completed by IHME and other research groups known as the Global Burden of Disease project. Here's a link to one of the project's interactive tools for exploring malaria deaths (below is just a screen grab ... the big red dot with lots of malaria is Nigeria):
"We have seen a huge increase in both funding and in policy attention given to malaria over the past decade, and it's having real impact," said Alan Lopez, a population health expert at the University of Queensland in Australia and Murray's lead partner on the disease burden project.
But the finding that adults make up a much larger proportion of the deaths, Murray said, means the global strategy may need to shift direction a bit. And the greater death toll, he added, means support for the global anti-malaria efforts will need to be stepped up as well.
Murray and his team found that even though many more adults die from malaria than had been assumed, malaria also appears to be, proportionately, a much bigger cause of all child deaths than most experts had been thought (e.g., more like 24 percent as opposed to earlier estimates of 16 percent).
They also found evidence the massive distribution of insecticide-treated bed nets have worked to reduce malaria deaths -- but the evidence of effectiveness from the complementary practice of indoor household insecticide spraying was equivocal.
Clearly, the biggest surprise here is in challenging the assumption that adults in malaria-endemic areas are immune to the parasite. Looks like adults need to be sleeping under nets as well, Murray said, and also be included in efforts to expand access to better diagnoses and treatments.
"Until now, the focus in malaria has mostly been on kids," Murray said.
"That's going to have to change."
Richard Horton, editor of The Lancet, said he expects the findings will be controversial and challenged by some. Murray's reports are "disturbing," Horton said, and disruptive to many organizations that have established strategies based on the official estimates and assumption that adults are at low risk of dying.
As Richard Knox of NPR reports, some already are contesting the findings:
"I would be very cautious" about the new estimates, Sarah Kline, director of the UK branch of the advocacy group Malaria No More told Shots. "It is a dramatic increase from what the WHO says, and it contributes to the overall discussion, but it's unclear if it will lead to significant policy change.
The tools to combat malaria are the same."
The study was funded by the Bill & Melinda Gates Foundation, which also provided the original seed money of $105 million to create the IHME at the UW in 2007 aimed at improving information and statistics in global health.