Dr Matt Cairns
A new study led by researchers from the London School of Hygiene & Tropical Medicine (LSHTM) has found that the seasonal prevention of malaria throughout certain regions of Africa could help to significantly reduce malaria attacks and child mortality associated with the disease. The team used their findings to produce a map to identify the locations within Africa that would most benefit from this form of treatment.
What did surprise us was the size of the identified areas in the Sahel and sub-Sahel regions. This belt extends from Gambia and Senegal in the West to Sudan in the East. Actually, when we saw the size of the population within that area and the scale of the potential impact, we were really surprised.
Dr Matt Cairns
Not only does seasonal malaria chemoprevention (SMC) represent a new weapon in the fight against malaria, but there also exists the potential for the method to become operational within a fairly small timeframe.
"Excitingly, this is something that is available to put into action immediately, so children will start to benefit from this approach now rather than in three or five years’ time," explains Professor Sir Brian Greenwood, one of the study’s senior authors. "The key is to ensure that the promise becomes a reality."
Even cautious estimates from the researchers, whose findings were published in the journal Nature Communications
, predict that SMC could save tens of thousands of lives every year. In trials published last year, where participants slept under new, insecticide-treated nets (ITNs), half received SMC treatment and half did not. SMC was successful in preventing around 80 per cent of severe and uncomplicated malaria cases. In a larger pilot trial, approximately 800,000 courses of the treatment have now been administered to children at risk from malaria.
I spoke to Dr Matt Cairns, Lecturer in Epidemiology at LSHTM, about how SMC can be used to protect African children from this most prevalent of infectious diseases…How does SMC differ from traditional methods used to combat malaria?
The key difference is that SMC represents a targeted form of control. Basically, it is given to a particular high-risk group – in this case, children under five years of age – and it would be delivered at a particular time of the year when malaria cases are at their peak. This means that the treatment is appropriate in certain areas of Africa where the patterns of malaria demonstrate seasonality. In our study we tried to establish the areas that would benefit from this strategy, and how expansive they were.How does the seasonal nature of this treatment impact upon its cost?
SMC is different to conventional treatment of malaria patients as it is a proactive approach designed to prevent malaria, rather than to react to and treat it. There are additional costs incurred when doing something like this, but in terms of the cost of each case of malaria that would be prevented, it’s quite good value. In certain contexts, it offers similar levels of value for money as other interventions that are available such as insecticide sprays and ITNs. Delivery by trained members of the community has been shown to be successful, will help to minimise costs, and, importantly, is also acceptable to the communities where it has been tried.
Were there any surprises amongst the locations that your research identified as suitable targets for SMC?
Map displaying areas that would most benefit from SMC
It is reasonably well known that certain areas of West Africa have highly seasonal malaria, particularly in light of the trials of SMC that have taken place over the last five to 10 years. What did surprise us was the size of the identified areas in the Sahel and sub-Sahel regions. This belt extends from Gambia and Senegal in the west to Sudan in the east. Actually, when we saw the size of the population within that area and the scale of the potential impact, we were really surprised.
Another aspect that was quite revealing was that according to the rainfall patterns there is quite a large area of southern and eastern Africa that might also be suited to this approach. This was not widely recognised before we conducted our research and it is something that we plan to look at in more detail.Is this the first time that these sorts of maps have been used in relation to tropical diseases?
There have been several other attempts in the past to look at the amount of malaria in different locations, and there has also been work done to look at the seasonality of malaria in a more general sense. However, this really is the first attempt to map such issues with a particular intervention in mind. We wanted to identify the areas in which SMC would be specifically appropriate. When we were selecting regions with seasonal malaria transmission, we focused on those in which the majority of the malaria burden occurs within three months of the year. This strategy was partly based on the fact that previous clinical trials have demonstrated that monthly courses over three months can provide a high level of protection.Your co-author, Professor Sir Brian Greenwood, contends that SMC could be put into action immediately. Who needs to act in order for this to happen?
This approach is now recommended within the official policy of the World Health Organization (WHO). I think that this is a really important first step in the process. The next stage, which hopefully will begin later this year, will involve fairly large-scale pilot implementation projects by National Malaria Control Programmes, perhaps with the support of NGOs such as Médecins Sans Frontières (MSF). We have had a really encouraging start.
If the pilot implementations are successful, they should provide the momentum for other areas and countries to provide SMC. Ultimately, the interventions would operate at full scale under the guidance of National Malaria Control Programmes, and so would be coordinated by ministries of health. Indeed, some of the trials that have been completed to date have been conducted in close cooperation with ministries of health. I hope that such involvement will result in treatment moving from the research side of things to implementation, faster than other interventions have done in the past.You have estimated that tens of thousands of lives could be saved each year with SMC. Would you expect the large-scale implementation of this intervention to involve any significant challenges?
Yes. I think that we could encounter several challenges. First of all, there has to be funding in place. Now that SMC has been recommended by WHO, it should be possible for countries to apply for support from either the Global Fund to Fight AIDS, Tuberculosis and Malaria, or from the President’s Malaria Initiative (PMI). But as far as malaria control tools are concerned, this is not particularly expensive. It costs in the region of $1.50 per child, per year, for this treatment.
Of course, there must also be the will to do this from the countries concerned, and generating this will is not always a small challenge. So far, the intervention has proven quite popular and it has certainly been well received by participating communities, according to our research. A number of staff from National Malaria Control Programmes have also expressed an interest in SMC. It still remains to be seen whether the potential challenges can be overcome.To what extent is it important for this approach to be supplemented by other anti-malarial tools such as mosquito nets and insecticides?
I think that this is a really important factor. Other control tools are absolutely integral to malaria control. In addition to the ones that you have mentioned, prompt diagnosis and the effective use of combined malaria treatments will remain the cornerstone of anti-malarial strategies. It is important to keep in mind that although SMC offers very good protection, we still need to employ it within the context of other available interventions.
Encouragingly, previous studies have shown that this approach is still valuable, even if children are already sleeping under good quality ITNs. The preventative potential delivered by the drugs, when combined with protection offered by other tools, are of clear benefit to the children. I think that this is one of the main reasons behind support for the intervention.
Key trials were conducted in Burkina Faso and Mali. Whilst all of the children involved slept under new ITNs, half received SMC treatment and the other half did not. The number of clinical cases and severe malaria episodes (where children would need to be admitted to hospital) were reduced by about 80 per cent amongst the children given SMC, despite the fact that all participants were using high-quality ITNs. These results show that SMC delivers substantial protection on top of
that offered by other tools.Will you be involved in the implementation of this approach?
I personally will not be involved in the implementation. Several of my colleagues at LSHTM and within the larger SMC taskforce will certainly be involved in the design and evaluation of implementation. I will, however, continue to work in this area. One thing that I am particularly interested in is whether this approach, or an adapted version of this approach, can be used in areas with longer rainy seasons. Until now, we have focused on areas where most cases of malaria occur within three months of the year, but it might be possible to adapt the treatment to cover periods of five or six months. If we are successful in our goal, we could cover a much larger area of Africa and many more children could be protected.