Counting Malaria Out: The drugs do work, getting them is the problem (updated)
According to Professor Chris Whitty, Head of Research at the Department for International Development (DfID), almost every death by malaria is avoidable. We have drugs that work and that are affordable. Yet there are still substantial numbers of deaths due to malaria. Why?
In a talk at the London School of Hygiene and Tropical Medicine (LSHTM) last Friday, Whitty highlighted one of them: deaths occur because people simply cannot get anti-malarial drugs.
“Those who need malaria drugs and those that are given malaria drugs are not the same group,” he said. The reasons for this are complicated, but the top three are:
- Many malaria patients do not seek care.
- Of those who do, most do not seek care from the formal healthcare sector.
Earlier I wrote that the drugs are affordable. But ‘affordable’ is a relative term. ACTs are relatively cheap if you live in Thailand and only get malaria once every so often. In parts of Africa, however, ACTs cost over $1.50 a course and people tend to suffer 3-5 bouts of malaria a year. That’s a lot of money considering the average person lives on $0.64 a day. And people have different ideas of what they are willing to pay for things, even medicines. Research has shown that the value consumers put on antimalarial drugs is less than their true market value.
Prices are coming down, but slowly and Whitty believes they are unlikely to fall enough. Again, there are many reasons for this. Growth of the plant from which artemisinin is derived requires land, something that is expensive to come by. It also costs a lot to extract and process. Moreover, it’s a risky business – the market is immature and with researchers developing synthetic artemisinin many companies are unwilling to take the risk of investing in the current process. Furthermore, the shelf life of artemisinin is short, raising significant problems with stock control and wastage.
Then there is the problem of distribution. The poorest patients will always go to the closest point for care. This will almost always be local retailers – even if they have to pay for them, it’s still cheaper than travelling to a hospital. And when I write ‘local retailers’, this isn’t necessarily a proper pharmacist, but often a general supply store. Worse still, most of the working anti-malarial drugs won’t even appear in such retailers.
Then there’s drug efficacy. This depends on several factors: whether the patient attends a doctor, the accuracy of diagnosis, prescription of the drug, the patient taking the drug course correctly. By the end of this, the efficacy of any drug is likely to be only 16 per cent in a population. This drops to 5 per cent if formal healthcare services aren’t involved at all (i.e. if people are buying their drugs directly from the local shop).
The problem, said Whitty, is not the lack of effective anti-malarial drugs, but getting them to the right people at the right time. Public health professionals are looking at a number of different ways to do this, including community involvement (giving the drugs to the community to distribute themselves when needed), subsidising drugs to reduce the price to get them into local retailers, and focusing on improving the formal healthcare sector.
None of these are particularly easy, given the complexity of healthcare in many countries. There’s also the risk of over-treatment (and with it, drug resistance). Flooding the market with anti-malarial drugs also doesn’t guarantee that the people you reach are necessarily those with malaria.
What we need alongside better drugs and better access to drugs, is better diagnosis. According to a 2007 study just a quarter of the cases that look like malaria are actually malaria. Two 2004 studies published in the Lancet and BMJ found that more than 50 per cent of those treated for malaria don’t even have the disease, and that mortality is almost twice as high for those that have been misdiagnosed for malaria.
According to Dr David Bell, a researcher from the World Health Organization (WHO), over half of all malaria cases are diagnosed on the basis of symptoms alone, contrary to the WHO’s recommendation that use microscopy for confirmation.
The trouble is, while microscopy is reliable, it’s neither quick nor easy to do without the right equipment and personnel. So, scientists have been working to develop an alternative: rapid diagnostic tests (RDTs) that can diagnose malaria from a blood drop using labelled antibodies. The result is an accurate diagnosis, but one as quick and simple to use as a home pregnancy test.
RDTs are now being rolled out all over the world. In Senegal a 2007 study found that the level of malaria reported had dropped by a third, and in India, they have helped save over a 1.5 million doses of artemisinin-combination therapy (ACT). Researchers are also working to make better RDTs with improved sensitivity, the capacity to detect different malaria strains and suitability for use in the tropics.
With a variety of RDTs, of varying quality, currently on the market Bell emphasised the importance of training healthcare workers in how to use them correctly. “You can’t just throw things out to the community and expect them to work.” Manufacturers must consider proper training manuals as being as important as the actual product itself, he said.
This will help to ensure that the tests are being used properly, which will help with the other challenge of convincing people that RDTs really work and that a null result really does mean they don’t have malaria. Microscopy diagnosis still accompanies the use of RDTs for this reason.
There are still a lot of problems for the malaria research community to solve. But improved diagnosis, better treatments and better treatment strategies are helping us win the fight against the disease. According to the World Health Organisation’s 2009 Malaria report, over one third of the 108 countries where malaria is endemic documented reductions in malaria cases of more than 50 per cent in 2008 compared to 2000. In countries that have achieved high coverage with bednets and drug treatment programmes, recorded cases and deaths due to malaria have fallen by 50 per cent.
There’s still much to do, but researchers are starting to think about the next challenges in malaria on the horizon. “We have the tools to identify and manage malaria as a common disease,” said Bell, “Now we need tools and strategies to manage it as a rare disease”.
You can access audio recordings and slides from the conference talks at the LSHTM malaria website.