Interview with Robert W Snow of the Centre for Tropical Medicine, University of Oxford, John Radcliffe Hospital and member of the Kenya Medical Research Institute/Wellcome Trust Research Laboratories.
Dr. Robert W Snow of the Centre for Tropical Medicine, University of Oxford, John Radcliffe Hospital and member of the Kenya Medical Research Institute/Wellcome Trust Research Laboratories.
Credit: Gregory Di Cresce/IRIN
For more than two decades, Robert Snow has lived and worked in Africa addressing the epidemiology, control and public health consequences of malaria. He has published more than 140 peer-reviewed journal articles and received the Chalmer's Medal for Tropical Medicine by the Royal Society of Tropical Medicine and Hygiene in 1999. Most recently, he has been responsible for bringing together a group of scientists interested in the public health policy of malaria and measuring the impact of malaria control investment. QUESTION: Why does malaria continue to threaten almost 40 percent of the world’s population?
ANSWER: You have to start with the United Nations. The UN overall has failed malaria-endemic countries simply by not providing any strategic direction. We know what you can do to control malaria – by using an insecticide-treated bed net. In communities, you can reduce all-cause childhood mortality by 16 percent or 17 percent. We don’t have another public health intervention of that scale. That’s a huge reduction, and it costs probably US $4 to cover a child with an insecticide-treated bed net (ITN). Small change, really. But up to 2003, less than 5 percent of children slept under an ITN.
It has not simply been a lack of money – money has been a problem up to now – but it has also been a lack of strategic direction. People in UN agencies such as UNICEF [the UN Children’s Fund], the World Bank, the World Health Organization [WHO], who have not come out strongly enough in favour of this intervention and in suggesting that it ought to be provided free of charge to those most vulnerable.
In fact, what these organisations have promoted is largely approaches that make poor people pay for ITNs – and poor people can’t afford it. So poor children remain vulnerable to malaria and continue to die from malaria.Q: What are your thoughts then on how the UN, particularly WHO, has dealt with the malaria treatment change to artemisinin-based combination therapies (ACTs)?
A: For a number of years we’ve known that drugs that are currently been used – like chloroquine and SP (sulfadoxine-pyrimethanine) – simply do not work. So a child presents unwell, is treated with a drug and 14 days later is still unwell in 50 percent of the cases across many countries in Africa.
Furthermore, we’ve also known for a number of years that there are new medicines that are indeed effective, can provide rapid cure, make the patients feel better, keep the patients free of infection for a long period and these are called ACTs. Now, despite knowing we had these drugs available and knowing they’ve been shown to work in clinical trials, there was reluctance on the part of WHO to come out unanimously and say that these are the drugs that should be promoted. Because of that ambiguity, countries retained drugs that didn’t work and kept using them. This went on for a number of years until about January 2004, which was a sort of watershed moment. That was when scientists working in Africa published an article in the Lancet titled, “WHO, the Global Fund, and medical malpractice in malaria treatment”. That prompted WHO and the Global Fund [to Fight AIDS, Tuberculosis and Malaria] to address their inadequacies and come out more strongly in favour of ACTs. Now we have 20-plus countries that are about to adopt or have adopted ACTs as their first-line therapy.
The problem there is that ACTs are a lot more expensive. African countries cannot afford to provide their populations with these medicines, which cost over $1 for a full-treatment course. We are critically dependent on the Global Fund supporting this initiative and other agencies, such as the World Bank, to look at more creative ways in which they can finance long-term drug delivery and drug supply.
Up to the end of 2005, there has been a rather appalling coordinated effort in terms of supplying strategic advice to countries. There has been a slow trickling of money at the beginning but then a major ratcheting up of monies available through the Global Fund. And now we are poised to make a difference. The next two years will be the acid test as to whether the UN can deliver on its promises.Q: There has been a lot written about the economic impact of malaria. What is the relationship between malaria and poverty?
A: Poverty can be seen to be working on two levels, the village level and the global level, when it comes to malaria.
Where it gets mediated at the village level is that families who have money can protect themselves. Families who don’t have money, can’t. It is as simple as that. Families who have money can access medicines rapidly. Where medicines that don’t work are the ones available in the government sector – wealthy families can go to the private sector and get medicines that do work. At those sorts of levels – at household levels – wealth is quite an important determinant. Q: And on the global level?
A: On the global level, if you took all the national data and asked, How much malaria is in a county and what is its gross domestic product? you can draw a nice regression line. That is what [economist] Jeffery Sachs does. And it is reasonably plausible at a global scale. But if you get down to national scales – take Kenya as an example – it is not as straightforward. Are the most productive areas in Kenya the ones with the least malaria? Probably not. Are areas with least malaria the least wealthy? Well, we know that is not true because in arid areas you’ve go all those nomadic populations who are incredibly poor and they don’t suffer from malaria. So at a national scale other things are influencing the relationship between poverty and malaria.Q: How is productivity affected by this affliction?
A: People do take days off with fever, but most of those fevers are not malaria. So there is loss of productivity due to general illness and more often than not malaria is lumped in with febrile illness. There have been no experiments of eliminating malaria and seeing what happens to productivity.
Some people like to use the argument that if you eliminated malaria from Dar es Salaam, Toyota and Microsoft would relocate there tomorrow, and that it is all to do with direct foreign investment. I’m far less convinced of that. If I was Microsoft, there would be a few other reasons why I wouldn’t go to Dar es Salaam other than malaria.Q: Your research team has spent a lot of time trying to compile accurate numbers on malaria. Why is this so challenging and so important?
A: Well, you can take the numbers offered from national health statistics, but that only covers those who go to health centres and, with luck, get recorded on a piece of paper and, with luck, get recorded in headquarters, and, with luck, get reported to WHO.
In Africa, I think there were 35 deaths reported for 2003. That is what happens in one district hospital in a couple of months. How can that be right? Yet the World Bank and WHO included those figures in their recent Roll Back Malaria [RBM] progress report. They included those numbers even though they’re just not credible or believable. Why do UN agencies insist on reporting things that are clearly wrong? Now part of the problem is that they’ve got no other source of information. Or, as they would say, “That’s all we got. That’s all countries tell us.” Well, that’s simply not good enough. So you have to be a lot more creative with your information and your epidemiological data.
What we have done – which is basically what most of our group does here and in Oxford – is try to develop models of risk across the world. What proportion of different countries is exposed to malaria risk? Then you can develop models where populations live in relation to malaria risk using climate and satellite imagery and so on. Once you’ve done that, then you have to have an estimate of what the likelihood of developing malaria in those different transmission areas. These are all the sorts of things we investigate.
So the bottom line is that what seems to have fallen off the radar screen is information that is vital to tracking the progress of RBM. Without reliable information on disease burdens in different regions of the world and intervention coverage, where you know what those interventions are likely to prevent, we cannot predict what is going to happen.Q: What are your thoughts on the targets of the 2005 Abuja Declaration targets?
A: I can see why people set optimistic targets. There is no point setting a target that looks a bit feeble because no one is going to buy into it. So for political reasons, targets are set high. It is not unreasonable to expect that 60 percent of pregnant women have access to intermittent presumptive treatment. It is not unreasonable at all – in fact, it is probably too low – to expect that 60 percent of children are protected with an insecticide-treated bed net. So those targets are perfectly valid and achievable, even within the timeline they gave themselves.
If I was in charge of RBM, I’d have made sure we had the right medicines in place much earlier. I’d have made sure that everyone would have gotten a free bed net with the measles vaccine campaign. How difficult can that be? To use an American phrase: It’s a no-brainer.
But RBM got all tied up trying to make sure that various stakeholders were satisfied, like the private sector and USAID [US Agency for International Development]. But irrespective of politics, those targets were achievable and are achievable.Q: Is this even true of the Abuja target to halve malaria mortality by 2010?
A: The mortality one was the one that did cause some concern for most of the scientists working on malaria in Africa. We know you can’t measure it. There is a huge error margin around the adequate description of a death attributable to malaria. There is but a handful of areas in Africa where malaria mortality is actually measured prospectively. These sites are called “demographic surveillance sites”. There are very few of them in Africa, but we know where they are. We also know that it requires quite a bit of an effort to record morbidity prospectively. These are research tools. We spend our lives trying to describe these events with precision and we know just how difficult it is.
To have a UN target put out there, such as the Millennium Development Goals or the Abuja targets, saying you are going to reduce the incidents of malaria by 50 percent or arrest its rising increase, you’ve got to be able to measure it and you’ve got to be able to measure mortality. Yes, the burden goal for RBM was halving the malaria burden by 2010. But you’ve got to be able to measure it. We know you can but it requires a huge amount of financial resources and research resources to do that. I think it is well worth doing. Still, somebody needs to fund that.Q: Has anything good come out of the RBM movement?
A: The one good thing that has come out of the Roll Back Malaria movement is there has been a real transformation in where malaria is on the health agenda of countries and international communities and international agencies. It is as high as it will ever get on the international health agenda at the moment.
Malaria is specially mandated as a disease of poverty. It also has [UN Secretary-General] Kofi Annan’s occasional attention, something you would probably never have heard of five years ago. At the international level there really is a huge amount of support. But the thing is, if you don’t see success soon, if you can’t demonstrate success soon, then that political support will wane.
The current political support has translated into financial support. You’d have to say there is a lot more money available to do the job now then there was five years ago. So now that the money is available, you need to demonstrate that you can make a perceptible difference. That will increase the flow of money. If you demonstrate you can do what you say you can do, that should keep the floodgates open for funding. If you don’t demonstrate any difference, then you’ll face donor fatigue and international fatigue, and malaria control will become another one of those interest areas like population explosion was 10 or 15 years ago.Q: Where do you see malaria vaccines figuring into the fight against malaria?
A: We will have a vaccine. It won’t be in the next 10 years, but I’m pretty convinced – despite it being elusive up until now – we’ll have it within the next 15 years. It might be an antidisease vaccine rather an anti-infective vaccine, however.
There are several candidates out there at the moment targeting different stages of the malarial parasite. The ones that are looking slightly promising at the moment are the ones more involved with reducing the risks of developing a blood-stage infection from the liver. They do offer some hope, but there is a lot of work to be done on them. It is 10 years down the line. But it is one of those things that if you don’t invest in it now, you will definitely not have it. You can guarantee that you will never have a vaccine if you don’t put two, three, five times more money into research and development.Q: What about the role of genetics, especially the genetic modification of mosquitoes?
A: That is one of those areas of blue-skies research. If you can sterilise enough male Anopheles gambiae and release enough numbers in small communities, you might have an effect. There are a lot of ethical issues with genetically modifying biological material to be released into environments. You know what it is like for genetically modified crops and how people get twitched about that? Well, genetically modified insects that bite you? There’s a lot of work to be done there, a lot of work.Q: Lastly, what is your general impression of where the fight against malaria is at the close of 2005?
A: There is definitely an opportunity before us. We sort of missed it five years ago with the Abuja targets, but it is still there for the grabbing. There is no doubt in my mind that you can provide effective medicines to 60 percent of those who need them and so on. So at the political level it is at a crossroads. There is no reason you can’t do the job.
From a biological point of view or clinical or epidemiological point of view, we can do a lot over the next five or six years, but we won’t solve the malaria problem. People need to know that. It is here to stay. We can contain it and we can stop the rising mortality by doing things better. We can reduce morbidity and mortality quite substantially in large parts of the world, but is not going to go away.