Malaria is one of the greatest public health problems of our era, and seasonality remains a key hurdle to tackling it, especially in areas of highly endemic transmission. Seasonal Malaria Chemoprevention (SMC) is a promising approach to malaria prevention in areas where the incidence of transmission is highly seasonal. The story of SMC transitioning from trial to campaign and gaining international recognition as a best-practice approach serves as an excellent model for how focused innovations can evolve into widely delivered public health practices. It should be instructive for the whole global health community. This Article explains the journey of SMC, from small-scale application to wider adoption as a global strategy. It describes its efficacy and contribution to global malaria control.
What is Seasonal Malaria Chemoprevention?
Seasonal Malaria Chemoprevention involves administering antimalarial drugs to a population (particularly children under the age of five), to reduce the likelihood of individuals contracting malaria during the high transmission season. The theory behind SMC is that there is a significant seasonality in malaria transmission in many areas of the world – ie, that mosquito populations, and hence malaria cases, increase rapidly at certain times of the year (often in line with climate and vector species) other times of the year they are much lower.
The Genesis of SMC
Early Studies and Local Trials
SMC grew out of initial research and small-scale local trials aimed at reducing the seasonality of the disease. Preliminary studies in West Africa found that giving drugs to children at regular intervals during the height of malaria season could dramatically lower incidence rates. These studies formed the basis for expanding the strategy.
Implementation in High-Risk Areas
The first countries to test SMC on a large scale were those in West Africa, where malaria is highly seasonal. Specifically, countries like Niger, Chad, and Nigeria developed pilot programs to deliver SMC effectively. As a result, these programs would provide valuable knowledge of how the packages can work in the context of existing in-country programs. Furthermore, they would help identify the challenges and logistical hurdles involved.
Key Components of SMC
Drug Regimen
SMC commonly consists of a course of the antimalarial drugs sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) administered sequentially over monthly periods during the malaria season. Selection of the drugs and regimen is based on the local pattern and intensity of malaria transmission as well as local profiles of drug resistance.
Target Population
The focus of SMC is children under five years old, whose immune systems are most vulnerable to severe malaria and associated complications. In some programs, SMC may also be offered to pregnant women and other at-risk groups, depending on the local epidemiology.
Delivery System
SMC is delivered via a community-based and a health facility-based approach. In many settings, community health workers would receive training to administer the drugs and check on families’ progress. This layering of approaches not only improves ‘coverage’ but also allows administration in remote areas and among communities and populations not covered by the health facility-based approaches.
From Local to Global: Scaling Up SMC
Proof of Concept and Evidence Generation
The local pilot programs and trials were enough proof of concept to justify a larger-scale rollout of SMC. Trials and observational studies showed that SMC reduced malaria incidence and mortality in children, especially when delivered by national programs and handed out in rural or migrant populations that were often overlooked. By 2007, enough evidence existed for international health organizations and donors to support the use of SMC on a large scale.
Global Endorsement and Integration
This led global health institutions such as the World Health Organization and the Roll Back Malaria partnership to see SMC as a promising and potentially universal seasonal transmission strategy, which then paved the way for its rapid adoption. In 2012, WHO formally recommended SMC as a critical strategy for malaria prevention in the Sahel and other areas with similar seasonal transmission patterns. This recommendation made it possible for SMC programs to be scaled up from local contexts to national and global levels.
Funding and Support
Large international donor commitments, such as the Global Fund to Fight AIDS, Tuberculosis, and Malaria and the President’s Malaria Initiative (PMI), have driven these SMC expansions by providing medicine, program implementation support, and monitoring and evaluation assistance.
Capacity Building and Training
Developing a program of SMC meant creating local capabilities for the management and implementation of the program. These include staff training, supply chains for drugs, and monitoring systems. Often this requires non-governmental organizations (NGOs) and international bodies.
Impact of SMC on Malaria Control
Reduction in Malaria Incidence
Countries trialing SMC have seen substantial decreases in malaria incidence morbidity and mortality. In Niger, children under five experienced a drastic fall in the number of malaria cases and hospitalizations due to SMC.
Improved Health Outcomes
But if the initial malaria-causing mosquito bite is not followed by a second, and the infection cannot continue, then SMC contributes to better overall health for children. This might mean a lower frequency of anemia, fewer hospital visits, and less time missed from school.
Community Acceptance and Participation
Enabling the delivery of SMC at the community level has contributed to high levels of acceptance and uptake. Local health workers and members of the community themselves facilitate access to eligible children and ensure that they receive preventive treatment.
Enhanced Surveillance and Monitoring
SMC is also helping to revitalize malaria surveillance and monitoring systems and, notably, improving knowledge about malaria transmission, providing evidence on optimal timings of malaria control interventions (such as spraying, distribution of insecticidal nets), and patterns of drug resistance.
Challenges and Lessons Learned
Drug Resistance
The use of antimalarial drugs in SMC programs also raises fears about drug resistance. We must monitor the treatment’s efficacy as a condition for continued use, and we are actively addressing resistance by modifying drug formulations or using alternatives.
Logistical and Supply Chain Issues
Coupled with supply chains to ensure that drugs arrive quickly and in the necessary quantities, this is a challenge. Suppose drugs run out during a campaign, or supply chains are delayed for days, meaning children don’t receive their drugs on the targeted day. These issues in logistics need more effort to ensure that SMC is effective.
Integration with Other Malaria Control Strategies
SMC is a key part of this strategy, but it should not be the only part. For any malaria control program, including SMC, to be effective, it must integrate into a comprehensive strategy that collaborates with other interventions, such as insecticide-treated nets, indoor residual spraying, and malaria case management.
Sustainability and Funding
SMC requires recurrent funding and continued political support. Integrating SMC programs into national health systems and securing long-term funding will be essential for maintaining their impact.
The Future of SMC and Malaria Elimination
Expansion to New Regions
With each new demonstration of the effectiveness of SMC, more areas with seasonal malaria transmission are likely candidates for expanding this strategy – and for adapting SMC approaches to each context and fitting them to local needs.
Integration with Elimination Strategies
SMC will contribute to the larger fight towards malaria elimination by reducing malaria transmission during peak seasons. However, as regions get closer to elimination, SMC programs will begin to need to be part of efforts to interrupt transmission and eliminate the remaining foci of malaria.
Innovation and Research
Going forward, there will need to be sustained research and innovation to improve SMC programs and to address newly emerging challenges, such as the development of new drugs, new drug delivery methods, and the consequences of drug resistance.
Global Collaboration
International cooperation and partnerships need to continue to make progress with SMC and malaria elimination. This includes intergovernmental coordination with international organizations, academia, and communities working together.
The ascent of Seasonal Malaria Chemoprevention from a local pilot to a global strategy provides convincing evidence that the most demanding public health problems can be addressed by targeted, evidence-based interventions that expand access to preventive treatment during peak malaria transmission seasons. SMC’s contribution to malaria control is likely to remain central to strategies aimed at eliminating malaria transmission, particularly in areas where it occurs seasonally.
