The number of worldwide malaria deaths over the past 30 years may have been more than double World Health Organization estimates, and mortality in those 5 or older has been overlooked, according to new research released Thursday by the Institute for Health Metrics and Evaluation.
The good news, researchers say, is that the number of malaria deaths sharply decreased from a peak of 1.8 million in 2004 to 1.2 million in 2010. According to experts, 2004 is when a number of global health organizations made a concerted effort to increase funding to fight the disease.
"The interventions that have been scaled up since 2004 have been phenomenally successful," says David Bowen, CEO of Malaria No More. "The world is making incredible progress against a disease that has been affecting human beings for as long as there have been human beings."
Bill Gates, whose foundation has donated millions to fighting the disease and developing a vaccine, has said he'd be "very disappointed if within 20 years we're not close to eradicating [malaria] globally." And in August, Ray Chambers, the United Nations secretary general's special envoy for malaria, set a goal for reducing malaria deaths to zero by 2015.
Still, according to IHME, the number of people dying from the disease is higher than previously thought—WHO estimated that in 2010, 655,000 people died from malaria. That underestimate came from misidentifying the number of adults who died from the disease, says Steve Lim, lead researcher at IHME and co-author of the report. It has long been thought that malaria acted somewhat like chicken pox—individuals exposed to it as a child are unlikely to suffer from it as an adult. The IHME report largely disproves that—about 42 percent of the 1.2 million malaria-related deaths in 2010 occurred in people over the age of 5.
"The traditional teaching in public health schools argues that adults exposed to malaria as a child develop immunity. They may have clinical malaria, but are not likely to die from it," he says. By going over death records, Lim's team was able to determine that many adults who died from a "fever of unknown origin" likely died from malaria.
Chambers, of the UN, issued a statement Thursday in response to the report, saying that it "confirms previous estimates that malaria deaths have declined by nearly one-third globally since 2004 … the consistency of the one-third decline in malaria-related fatalities is what is most compelling."
But it's unlikely the world will meet Chambers' goal of eliminating malaria deaths by 2015, according to Lim. If malaria-related deaths continue to decline at the same rate, there will be fewer than 100,000 fatal malaria cases worldwide by 2020.
"What our study suggests," he says, "is that one might have to revise some of those goals that have been set."
Malaria experts worry that funding sources might soon dry up. The Global Fund, one of the world's largest financial supporters of the malaria fight, announced it has canceled a round of funding. "It would be a terrible irony if at the moment we're making great and unprecedented progress we pull back from the commitment," Bowen says. "The gains of recent years are not a guarantee. It requires an ongoing commitment."
Phil Thuma, an American pediatrician working in rural southern Zambia, says that in 2000, his clinic, the Macha Malaria Institute, had 106 malaria deaths—in 2011, it only had one. That mirrors the rest of Zambia, where the number of malaria-related deaths declined from 16,300 in 2000 to 8,750 in 2010.
"We've had a 98 percent decrease [at my clinic]," he says. "But if the funders abandon us now, we'll be in bad shape."
That's because treating malaria isn't cheap. A potential malaria vaccine is always "just around the corner," says Thuma, but developing it is costly. Insecticide-treated bed nets have to be replaced every three years, and antimalarial drugs need to be produced, distributed, and taken regularly.