A new analysis of malaria mortality published in The Lancet this week suggests deaths to the parasitic disease worldwide have been grossly underestimated, especially in adults. If confirmed, the study has huge implications for how large amounts of charity money are spent in controlling the disease. However, the study also finds that thanks to improved prevention and treatment, such as anti-malaria drugs and insecticide-treated bed nets, deaths to malaria are falling rapidly.
Researchers from the Institute for Health Metrics and Evaluation ( IHME) at the University of Washington in Seattle in the US, estimate that nearly 1.24 million people died from malaria in 2010, nearly double the figure estimated by the World Health Organization (WHO) for the same year.
They say previous studies have overlooked many deaths because they have assumed most of the victims are children under 5. But in their analysis, the IHME researchers found that in 2010 the disease killed more than 78,000 children aged 5 to 14, and more than 445,000 people aged 15 and older, suggesting that over 40% of all malaria deaths are of people aged 5 and older.
The lead author of the study is Dr Christopher Murray, director of the IHME. He told the press:
“You learn in medical school that people exposed to malaria as children develop immunity and rarely die from malaria as adults.”
“What we have found in hospital records, death records, surveys and other sources shows that just is not the case,” he added.
One of the main reasons Murray and colleagues’ new estimate is so much bigger than previously thought is because they included verbal autopsy data, where researchers interview relatives of the deceased to find out the cause of death.
Reseachers from IHME and other institutions wrote an article in a special issue of Population Health Metrics in August 2011, promoting the science of verbal autopsy.
The researchers found verbal autopsy was especially valuable in estimating malaria deaths in India, where they have been grossly under-counted in both children and adults. They suggest more than 37,000 people in India over the age of 15 died from the parasitic disease in 2010.
But the chances of dying from malaria in India have also declined rapidly since 1980, they said.
Overall, annual global malaria deaths rose rapidly for around 20 years since 1985, before peaking at 1.8 million in 2004. After that they have fallen every year, and between 2007 and 2010, they have fallen by more than 7% each year.
The biggest impact on reducing deaths to malaria has been a huge increase in the use of insecticide-treated bed nets and artemisinin-combination treatments (ACTs), say the researchers.
This has been possible because of organizations like the Global Fund to Fight AIDS, Malaria & Tuberculosis, set up in 2001, and the formation of WHO’s Roll Back Malaria, Malaria No More and Nothing But Nets.
The money spent every year on fighting malaria has also grown enormously: in 2009, the total reached more than $2 billion. Only eight years earlier, in 2001, the total was around $0.25 billion, according to the IHME, who last year reported that homes with at least one insecticide-treated bed net were linked to a 23% lower rate of child deaths.
Progress in tackling malaria is especially visible in Africa. Countries like Zambia and Tanzania saw deaths to the disease fall by over 30% from 2004 to 2010.
The authors emphasize it is crucial to hold onto these gains and not allow the global economic situation to stem the flow of funds.
IHME reported a few months ago that growth in funds to develop assistance for health had slowed down significantly between 2009 and 2011. Recently, the Global fund announced it was going to cancel the next round of funding. These trends do not bode well for malaria programs, say the authors.
Co-author Stephen Lim, Associate Professor of Global Health at IHME, said:
“If the Global Fund is weakened, the world could lose 40% of all the funding dedicated to fighting malaria.”
He said a loss of that size would definitely threaten the health of people in countries where malaria is rife, many of which are also 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,” said Lim.
An accompanying editorial in the same issue of The Lancet calls for urgent action to review these findings and re-align priorities in malaria control.
It says the new findings suggest malaria might be a far more important cause of deaths in childhood than previously thought, which holds serious implications for childhood survival programs. The study also shows that malaria is a greater long-term threat to adult health, meaning that malaria control and eradication programs should also be paying more attetion to this group.
The journal editors write that the study also underlines the important and urgent need to revitalize our health information systems:
“We need reliable primary cause of death data to ensure that trends in malaria mortality are readily and reliably monitored — and acted upon.”
They recommend WHO should now carry out a new set of technical and policy analyses, and give the task to a much broader group of experts than the 15 members that currently comprise the WHO’s Malaria Policy Advisory Committee (MPAC).
The new body should review the new findings and their implications for malaria control programs. The body should include experts in child survival, and country representatives.
“This opportunity needs to be grasped with urgency and optimism,” they write.
The study was funded by the The Bill & Melinda Gates Foundation, and is part of an ongoing series from the Global Burden of Diseases, Injuries, and Risk Factors 2010 Study, which last year released global figures for child mortality, maternal mortality, breast cancer, and cervical cancer. Figures covering other diseases are expected to be released later this year.
Written by Catharine Paddock PhD