A new study using disease modelling – published last month in the Malaria Journal by a team of researchers from organisations including Northwestern University, Malaria Consortium, the National Malaria Elimination Programme in Nigeria and the Institute for Disease Modelling – has found a complementary effect between perennial malaria chemoprevention (PMC) and the malaria vaccine RTS,S in controlling malaria in children under two. The findings will be used to inform policy decisions in countries where the malaria burden in young children remains high.
Despite the availability of preventive and therapeutic malaria interventions, malaria continues to have a devastating impact on people’s health in endemic areas – infecting around 247 million people each year, with most clinical and severe cases occurring in under-fives. Innovations such as the RTS,S malaria vaccine – recommended by the World Health Organization (WHO) for use in children in sub-Saharan Africa in 2021 – are expected to affect how and where existing malaria interventions, such as the use of chemoprevention in children, is deployed in the future.
“We believe that vaccines have the potential to make a substantial contribution to malaria control among children under two but these will need to be used in combination with other effective control measures and as part of wider health system strengthening efforts. In many countries in sub-Saharan African where the burden of malaria is high, vaccination coverage remains below the target of 80 percent. We must therefore continue to support endemic countries to strengthen health systems and collect vital data to determine the impact of these interventions in the real world and monitor the relationship between chemoprevention use and resistance to the drugs used, to inform policy decisions”, commented Dr James Tibenderana, Malaria Consortium Chief Executive and co-author of the study.
PMC – formerly termed intermittent preventive treatment in infants or IPTi by WHO – involves treatment courses of antimalarial medicines in areas with moderate to high malaria transmission given to children up to the age of 24 months at specific ages throughout the year as a preventative measure. The previous recommendation was designed to be delivered alongside routine immunisations given at ten weeks, fourteen weeks and nine months of age through the WHO’s immunisation programme, Essential Programme for Immunization (EPI). Until recently, Sierra Leonne has been the only country to implement this intervention.
Last year, the WHO removed the fixed-dose number and timings for malaria chemoprevention from its Malaria Guidelines. The new flexibility in scheduling and timing is designed to allow countries to make appropriate adaptations according to local contexts. Mozambique has recently announced the addition of implementation of PMC to its malaria control efforts and has begun to implement the intervention in some districts. The PMC schedule of doses tested as part of the study found that this intervention can substantially reduce clinical and severe cases in the first two years of life in areas with high rates of malaria and that there was a complementary effect between PMC and the malaria vaccine, which could be provided in a schedule of four doses (or more) in children from five months of age.
Nigeria, which accounts for around 27 percent of all global malaria deaths, was selected as the study setting for the epidemiological MODeling (EMOD) software. The model was used to computer-simulate PMC doses given to under-twos alone or in combination with the malaria vaccine and their behaviour and interactions with one another.
It is expected the results of this study will be used to inform phased implementation studies, strategic considerations of PMC adoption in countries, as well as subsequent modelling studies that can support countries to collect vital data to determine the impact of these interventions in the real world and monitor the relationship between chemoprevention use and resistance.