February 3, 2012
Lancet Study: Malaria Death Rates Higher Than Expected
A new probe into the perils of malaria has found that 1.2 million people die each year from the disease, 50 percent more than previously thought, and 42 percent of those numbers occur in older children and adults, railroading long-believed assumptions that mainly young children die from the disease.
The new research, conducted by the Institute for Health Metrics and Evaluation at the University of Washington, states that, even so, the number of deaths has fallen drastically due to efforts to combat the disease in recent years.
IMHE researchers said that deaths from malaria have been missed in previous studies because of the assumption that mainly young children under the age of 5 died from the disease. But IMHE found that more than 78,000 children aged 5 to 14, and more than 145,000 people ages 15 and older have died from malaria in 2010, meaning 42 percent of all malaria-related deaths were in those 5 and older.
“You learn in medical school that people exposed to malaria as children develop immunity and rarely die from malaria as adults,” said Dr. Christopher Murray, IHME Director and the study´s lead author. “What we have found in hospital records, death records, surveys and other sources shows that just is not the case.”
Published in the British medical journal The Lancet, the study suggests 1.24 million people died from the mosquito-borne disease in 2010. This is nearly twice the estimated malaria-related death toll of 655,000 that the World Health Organization previously released.
Using an analysis of reports from 1980 to 2010, IMHE concluded that worldwide deaths from malaria had risen from 995,000 in 1980 to a peak of around 1.82 million in 2004, before falling to 1.24 million in 2010.
Researchers say the biggest drivers of the decline in malaria deaths have been the increase in the use of insecticide-treated bed nets and a new class of better drugs. This process was accomplished with the support of the Global Fund to Fight AIDS, Malaria & Tuberculosis in 2001 and the creation of organizations focused on fighting malaria, such as the WHO´s Roll Back Malaria, Malaria No More and Nothing But Nets. Funding for the fight against malaria has grown from less than $250 million annually in 2001 to more than $2 billion in 2009, according to IMHE reports.
The researchers said malaria eradication was not a short-term fix. But if the decrease in deaths continues as it has from the 2004 peak, “malaria mortality will decrease to less than 100,000 deaths only after 2020,” they wrote.
“We have seen a huge increase in both funding and in policy attention given to malaria over the past decade, and it´s having a real impact,” said Dr. Alan Lopez, head of the School of Population Health at the University of Queensland and a study coauthor. “Reliably demonstrating just how big an impact is important to drive further investments in malaria control programs. This makes it even more critical for us to generate accurate estimates for all deaths, not just in young children and not just in sub-Saharan Africa.”
One of the most important factors in identifying new estimates of malaria deaths was the use of verbal autopsy data. Researchers interview relatives of someone who recently died to identify the cause of death. Verbal autopsy data were especially important in India, where malaria deaths have been hugely undercounted in both children and adults. IMHE found that more than 37,000 people over the age of 15 in India died from malaria in 2010.
“Right now we don't actually have any reliable primary numbers for malaria deaths in some of the most malaria-infected regions of the world, so what numbers we have come from estimates,” Richard Horton, editor for The Lancet, told BBC News. “What this paper reports is a new way of estimating the number of malaria deaths, where they´ve used additional data sets and improved mathematical models from calculating mortality.”
Fighting malaria has made much progress in places such as Tanzania and Zambia, which has seen deaths drop dramatically between 2004 and 2010. In Africa overall, the progress has been significant, given that malaria deaths there accounted for 25 percent of all deaths in children under age 5 in 2010.
“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 Lopez.
But researchers warn that those gains could be reversed if global economic troubles continue to hold back funding efforts. IHME reported in December that growth in development assistance for health had slowed greatly between 2009 and 2011. The announcement by the Global Fund in November that it would cancel its next round of funding casts a cloud over the future of malaria programs, the researchers note.
“There has been a rapid decrease in malaria mortality in Africa because of the scaling up of control activities supported by international donors,” the study said. “Donor support, however, needs to be increased if malaria elimination and eradication and broader health and development goals are to be met.”
“If the Global Fund is weakened, the world could lose 40 percent of all the funding dedicated to fighting malaria,” said Stephen Lim, Associate Professor of Global Health at IHME and a co-author on the study. “That kind of loss of funding poses a definite threat to the health of people in countries with a high malaria burden, which in many cases are some of the poorest countries in the world. We need to think of ways to fill funding deficits in order to insure continued progress on malaria mortality.”
The research was funded by the Bill and Melinda Gates Foundation.
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