Malaria kills more than 1.2 million people worldwide a year, nearly twice as many as previously thought, according to new research published on Friday that questions years of assumptions about the mosquito-borne disease.
Past studies had overlooked hundreds of thousands of deaths because they had wrongly assumed malaria overwhelmingly killed babies and focused their findings on under-fives, said the study by the Institute for Health Metrics and Evaluation (IHME) in the United States.
The new study, published in The Lancet medical journal, found 42 percent of deaths were actually among older children and adults.
The higher number of victims showed the need to increase funding to fight malaria, even as governments came under pressure to cut their aid budgets amid the global economic crisis, said the researchers.
“You learn in medical school that people exposed to malaria as children develop immunity and rarely die from malaria as adults,” said Christopher Murray, who led the study as IHME Director. “What we’ve found in hospital records, death records, surveys and other sources shows that just is not the case.”
In their work, which used new data and computer modeling to build a historical database for malaria between 1980 and 2010, they found that more than 78,000 children aged five to 14, and more than 445,000 people aged 15 and older died from malaria in 2010. This means more than four in 10 of all malaria deaths were in people aged fives years and older.
Overall, malaria deaths worldwide rose from 995,000 in 1980 to a peak of 1.8 million in 2004, before falling again to 1.2 million in 2010, the study found.
The World Health Organization’s (WHO) latest global report said the estimated number of malaria deaths fell to 655,000 in 2010, almost half the number in the IHME study.
The WHO, a United Nations agency, said on Friday it stood by its figures and said that much of the data used in the Lancet study had been based on verbal testimony by relatives of how people had died, not on laboratory diagnosis of samples.
“So we would say that again the great majority of deaths would be in children under five and we stand by our estimates,” WHO spokesman Gregory Hartl told a news briefing in Geneva.
Both studies showed a downward trend in deaths in recent years, thanks largely to the use of anti-malaria drugs and insecticide-treated bed nets.
The new findings are part of an ongoing series generated by the Global Burden of Diseases, Injuries and Risk Factors 2010 Study.