What is seasonal malaria and what challenges does it present to malaria control progress?
Seasonal malaria refers to the period within which we have the most malaria cases and deaths, because of high transmission. During this rainy period of around four months, young children get bitten by mosquitos more frequently and end up with high levels of infection, which are often followed by life-threatening episodes of severe anemia.
There are regions in sub-Saharan Africa that are more affected when it comes to seasonal malaria, particularly in the Sahel. Seasonal malaria is a big problem in Ghana, for example, especially in the northern part of the country. You often find that three out of ten children will have malaria during that time, which is quite huge.
The burdens of both seasonal and perennial malaria are key issues that require our attention, and any new interventions that can reduce that burden are important to us.
What is the current approach to preventing seasonal malaria, and how much progress can we make using the tools and strategies we have today?
Historically, the approach has been to enhance malaria control just before the high transmission season. This includes things like enhancing use of bed nets, ensuring availability of supplies for management of clinical cases and enhancing indoor residual spraying in places where it’s used. In more recent years, seasonal malaria chemoprevention (SMC) has also been used, where children are given treatment courses of an antimalarial medicine during that period of high malaria transmission.
The key challenge here is how to deliver the medications or interventions right when they are needed. This can be logistically burdensome, but it has been implemented very well in places like Ghana, Burkina Faso and Mali.
In the last decade, there has been progress towards malaria prevention and control in quite a number of countries, but there is still a heavy residual burden that we have to nail down. The burden in sub-Saharan Africa has come down slightly, and the implementation of bed nets, for example, has increased from close to 3% to 60-70% in some areas, but progress to reach more people appears to have leveled off. We’ve also moved from non-efficacious medications to very effective ones, like artemisinin combination therapy. But there are still many children at risk, and a lot more to do, with more concentrated efforts required in specific countries.
When it comes to malaria control, we need to deliver the most appropriate interventions for any given area to have the most impact. In areas where SMC is available, that should be enhanced. In places where malaria is perennial, other methods should be used. Multi-faceted and culturally acceptable approaches are always key.
What do you think the results of this new study could mean for the continent?
We are looking for interventions to prevent malaria among children who are the most vulnerable, so any combination of safe and efficacious interventions that reduces that burden is welcome.
This new study is good news, and the implication is that we now have an additional tool to further bring down the burden of malaria, especially in places where it’s the highest. This combination of RTS,S and SMC has been shown to reduce child morbidity and mortality, and we know we need to reduce that residual burden on the continent, so this is really welcome.
How might RTS,S seasonal use fit into future malaria control strategies?
The question of how RTS,S will be implemented has been on the table for several years now, since the time when I started working with colleagues on clinical trials for the vaccine. We’ve always asked ourselves that question. Today, we are witnessing it being implemented in three countries in sub-Saharan African: over 2 million doses have been given so far, and we haven’t witnessed any major implementation challenges. This tells us that if there is commitment to implement a new intervention within the health system, it will be done. Therefore, implementing RTS,S with SMC into the routine health system may seem challenging today, but it can be done with commitment and flexible innovations.
The pilot has been successful for several reasons. First, the three countries that were chosen to assess the feasibility of delivering RTS,S already have existing and very well set-up infrastructure for immunization. But I also know that there are other countries in Africa that do have that infrastructure in existence. Overlaying that implementation on the existing infrastructure meant that we just needed to adjust a little bit and given the interest and the will to do it, that adjustment was successful.
The other part is that there’s always been the need for something else to deal with malaria by community members, so anything that can drive down the burden is likely to be accepted. Every woman in Ghana, or in Chad, or in northern Nigeria has children who have experienced malaria or knows a mother whose child has suffered from malaria—if not died from it. So there is that community demand for a vaccine or intervention to deal with malaria. The demand has been crucial.
Another important part is the tremendous commitment by the countries leading this and by partners like the World Health Organization (WHO), PATH and donors for the implementation. Given all these facets, if the same amount of energy is put into the use of RTS,S and SMC, the burden of malaria will come down. These factors have led to the successful implementation of the pilot.
As a malaria scientist and public health strategist, what new research or programmatic questions come to mind based on the results?
One new programmatic question that we should examine is what it will mean for communities to take two preventive interventions next to each other. We need to understand how the community will perceive it, and how they will handle any other episodes of illness. Would they, for example, think that RTS,S and SMC is a magic bullet, and therefore if a child has a fever it’s likely to be something else, and not malaria? We need to get that from community members and design key messages around RTS,S and SMC implementation.
We also need to really understand the cost-effectiveness of the two interventions when used together.
Another key factor with the roll out of any new intervention is acceptance by health professionals themselves, and we need to assess their on-going acceptance of these interventions and the personal challenges they would face.
I can share experiences from our approach during the RTS,S malaria vaccine trials. The key thing is to involve key policy makers and stakeholders right from the start, when the studies are being conducted. You need to get people on board early so they understand the data that is coming out from the trials, and already start thinking about how to implement it if the trials prove useful.
Finally, the SMC trials are done within a limited setting, and so this should be repeated in other places to ensure we see the same results, specifically in areas where there is a significant burden of malaria without so much seasonality. We could look at this in areas with perennial malaria and see if it could be beneficial.
What could these results mean for Ghana and other countries with high rates of seasonal malaria transmission?
If regulatory authorities and ministries of health accept to implement this combination as an intervention in areas where the burden is high, given the data that we know, this could have a significant impact on child mortality and morbidity from malaria. This is likely to reduce the burden of malaria in our setting.
We should also put in place strong pharmaco-vigilance studies to make sure we capture any adverse events that may come up, and then report them, discuss them and act on them immediately.