The American Society of Tropical Medicine and Hygiene’s (ASTMH) Annual Meeting is one of the world’s most important meetings of global health practitioners, researchers and funders. While the rainy climes of Seattle, where this year’s annual meeting took place earlier this month, is a distant geography from the countries and communities where Malaria Consortium supports seasonal malaria chemoprevention (SMC) campaigns, the rain does at least represent a linkage between the meeting’s host city and where the work is taking place.
It is the seasonal rains in parts of Africa that bring with them a proliferation in the mosquito population and therefore an increase in malaria incidence. SMC campaigns are conducted during these rainy seasons in many areas and have been shown to contribute to a significant reduction in malaria cases among children during this period of the highest risk of infection.
However, the debate around SMC – how and where it is used, which drugs are used, and what its ongoing scale-up means for drug resistance – is not settled. New consolidated guidelines on malaria, published by the World Health Organization (WHO) in June 2022, give more flexibility to malaria-endemic countries to adapt malaria prevention and control strategies, underlining the need for local, context-specific evidence.
Malaria Consortium used the ASTMH Annual Meeting as a platform to share our latest research on these issues and advance the conversation with the wider SMC and tropical medicine research community. Here are some of the highlights and key takeaways:
1. The case for SMC outside of the Sahel
Through the SMC Alliance, we co-chaired a symposium ‘Implementing SMC in new geographies’, including the presentation of findings from implementation studies in Mozambique and Uganda, where SMC had not been used before. Results from non-randomised trials showed that children in districts where SMC was distributed were 86 percent and 92 percent less likely to develop clinical malaria than those in non-SMC districts in Mozambique and Uganda, respectively.
We also conducted cluster-randomised controlled trials in both countries to gather more robust evidence of the effectiveness of SMC. Dr Balthazar Candrinho, the Programme Manager for Mozambique’s National Malaria Control Programme (NMCP), presented preliminary results from Mozambique that show that children in the intervention arm had a 77 percent lower risk of having a malaria episode (confirmed by a rapid diagnostic test), during the peak transmission season, than children in the control arm. The cluster-randomised controlled trial in Uganda is ongoing and results will be available in 2023.
These are extremely positive preliminary results, which support the case for scale-up of the intervention. Final results from the studies, in addition to those from a smaller study in South Sudan, are to be published in 2023.
Malaria Consortium’s Country Technical Coordinator in Nigeria, Dr Olusola Oresanya, also presented observations from Nigeria where we have worked with partners to expand the reach of SMC from the Sahelian states in the north of the country to states further south, which also experience a rainy season. This work contrasts with the studies in Mozambique, Uganda and South Sudan, where SMC had not been implemented previously, as it expands on how new geographies within Nigeria can benefit from SMC. Only the Sahelian states in the far north of Nigeria have historically deployed SMC.
2. Updated SMC guidelines prompt discussion on SMC parameters
The recently updated WHO consolidated guidelines on malaria no longer specify strict criteria on seasonality, number and timing of cycles, age range or drug choice. This marks a significant change in guidance since the initial policy recommendation for SMC was made by WHO in 2012. The SMC symposium was a forum for discussion on these issues and underlined the importance of collaboration between health authorities, SMC implementers and researchers as the pathway for future implementation is agreed. There is a need to generate more evidence of the potential impact of changing the parameters for the deployment of SMC and it is likely that context – for example in terms of resistance profile or transmission intensity – will play a key role.
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