Unlocking the potential of preventive therapies for malaria
Interview with Dr Andrea Bosman, Coordinator of the Global Malaria Programme’s Prevention, Diagnostics & Treatment Unit
For how long have preventive therapies been used to fight malaria?
Some of the very first efforts to control malaria relied on using antimalarial medicines as preventive interventions. In the early 1900s, before WHO was established, malaria researchers tried different strategies like regular large-scale treatment and chemoprophylaxis campaigns. None of these strategies proved to be effective and by the 1980s, they were abandoned.
A turning point was in 1994, when a major study conducted by the Centers for Disease Control (CDC) using intermittent preventive treatment in pregnancy (IPTp) for the first time was presented and reviewed by WHO experts. Malaria infection during pregnancy carries serious risks for the mother and her child. Participants in the study were administered two treatment courses of the antimalarial sulfadoxine-pyrimethamine during the second and third trimester, which was found to be very effective in reducing maternal anaemia and low birth weight. The study led WHO to recommend adoption of the policy in all areas with moderate to high malaria transmission in Africa.
How has uptake of IPTp progressed?
Programmatic adoption started around 2003, but it wasn’t until 2008 that we started seeing countries really implementing the policy. Based on additional evidence, WHO now recommends that pregnant women take preventive treatment at routine antenatal care visits starting after the first trimester, starting as early as possible during the 2nd trimester and given at least 1 month apart. Between 2010 and 2015, there was a five-fold increase in the number of women receiving at least 3 doses in 20 of the 36 countries that have adopted the policy. But uptake hasn’t happened nearly as fast as we would like. Sixty-nine percent of pregnant women are still not receiving three or more doses of IPTp.
In 2007 WHO recommended a similar intervention for infants, called intermittent preventive treatment in infants (IPTi). If you give the antimalarial sulfadoxine-pyrimethamine to infants with routine vaccination – usually at 10 weeks, 14 weeks, and around 9 months of age – children have less clinical malaria and are better protected from anaemia. However the adoption of IPTi has also been very limited. Currently, the approach is being piloted in Sierra Leone.
What have been some of the barriers to adoption of IPTp and IPTi?
The issue is complex. The original research has been led by the malaria community, but successful implementation relies heavily on the collaboration of other programmes, as well as having additional funding to be able to do so. For example, reproductive health and maternal and child health programmes need to be the ones implementing IPTp, and vaccination programmes really need to implement IPTi. But when funding is tight and programmes have their own budget priorities, where does the money come from? Improving ownership among these groups would help significantly expand access to these important tools.
A third way preventive treatment is being used is in seasonal malaria chemoprevention (SMC). Can you talk a little bit about this approach?
The vast majority of malaria illnesses and deaths occur in children under five years of age. SMC protects this vulnerable group through the administration of malaria treatment at monthly intervals during malaria transmission season only – a period usually lasting around 3 to 4 months.
Uptake of SMC has been incredibly fast. In fact, it’s one of the fastest policy uptakes we’ve seen, in terms of the speed of adoption. Many agencies and major donors have mobilized around the approach and in 2015, there was actually a global shortage of the drugs used for SMC because of the exponential increase in demand. Production capacity has since increased to meet the need.
Why was uptake so quick?
SMC is different from IPTp and IPTi in the sense that it is implemented as a campaign operation that national malaria programmes themselves can direct. Community health workers are trained to administer the medicines, and go door to door to distribute them to children where they live. It’s very effective, and affordable, too. Protecting a child for an entire malaria transmission season only costs about US$ 5.
Early research indicates that SMC can reduce malaria cases in children by 75%, which is incredible. It means that robust implementation of SMC could have the potential to help us achieve one of the key milestones of the Global Technical Strategy for Malaria (GTS): on reducing malaria case incidence and mortality by 40% by 2020. In addition, vibrant research is currently being conducted on SMC and IPTp, and new tools are being developed that could make these strategies even more effective. The potential of innovation in this area is very exciting.