Historically seen as a niche for specialist use, seasonal chemoprevention has developed into a powerful weapon against malaria, particularly in regions of intense seasonality of disease. Its success has been most well-documented in Africa, but there is a growing momentum to investigate seasonal chemoprevention in other settings where it may have a role. In this review, we explore the seasonal chemoprevention of malaria. Specifically, we assess its effectiveness in Africa and, additionally, discuss how this adaptable intervention can be adopted and implemented in seasonal malaria regions beyond the African continent.
Understanding Seasonal Chemoprevention
Seasonal Chemoprevention (SCP), on the other hand, consists of administering an antimalarial drug to populations during the high-risk seasons of malaria transmission to reduce malaria incidence and prevent severe cases during periods when transmission is highest as compared with the rest of the year. SCP is effective in areas with seasonal patterns of malaria transmission where peak transmission occurs during well-defined periods, generally months of the year.
Core Components of SCP:
- Targeted Medication: During the peak of the transmission season, healthcare providers administer the antimalarial drug of choice—typically artemisinin combination therapies (ACTs), often supplemented with sulfadoxine-pyrimethamine (SP)—to those at highest risk.
- Coverage: Achieving high coverage is crucial; therefore, it typically involves mass drug administration (MDA) to ensure that as much of the population as possible receives treatment.
- Monitoring and Evaluation: Furthermore, ongoing monitoring and evaluation of SCP impact are necessary to track changes in transmission. This approach will help keep pace with evolving patterns of drug resistance and, in turn, improve the tailoring of strategies to the local epidemiological context.
Success Stories in Africa
SCP effectively reduces malaria morbidity and mortality in vulnerable populations, especially young children, in many African countries, including most of the Sahel region.
Key Successes:
- Mali: In regions of this West African country with very seasonal malaria transmission, studies show that implementing SCP has significantly reduced the incidence of severe malaria and hospital admissions during the high transmission season.
- Burkina Faso: Burkina Faso has also experienced the benefits of SCP, reporting lower rates of malaria and improved child health outcomes. The programs have received praise for their high and consistent coverage, as well as effective drug management.
- Niger: In Niger, seasonal chemoprophylaxis has prevented the peak of malaria cases, suggesting that this strategy could improve public health in highly endemic areas.
Expanding SCP Beyond Africa: Opportunities and Challenges
1. Potential in Asia
Malaria public health is a major concern in South and Southeast Asia, epitomized by the word ‘Delhi’ affectionately coined by Britons for the disease. While transmission patterns in Africa and South and Southeast Asia are different, one might expect similar SCP potential in both areas.
- Seasonal Transmission Patterns: Certain parts of South and Southeast Asia have seasonal malaria transmission patterns, such as areas with monsoon rainfall. In these locations, SCP could be modified to target peak seasons.
- Drug Resistance: Extensive resistance to antimalarial drugs is present in some parts of Asia. Adding newer drugs to the SCP and maintaining it to include factors such as resistance could improve its effectiveness.
- Infrastructure and Logistics: SCP implementation in Asia will require good healthcare infrastructure to ensure high coverage, and effective logistics to ensure high adherence.
2. Opportunities in the Americas
There are malaria problems in Central and South America but the epidemiology is different. SCP in these regions may involve:
- Localized outbreaks: in some places, malaria transmission might be seasonal or associated with particular outbreaks. SCP could effectively target outbreaks and prevent recurring cycles of transmission.
- Integration with Existing Programs: Integrate SCP into existing malaria control initiatives, such as vector control and case management, to boost their overall effectiveness.
- Challenges: Political instability and other challenges, like access to resources, will make SCP hard to implement in some places.
3. Exploring SCP in the Pacific Islands
In the Pacific Islands, malaria is transmitted unpredictably, but SCP could provide a means of outbreak control:
- Targeted Interventions: SCP could be applied focally in response to particular outbreaks or seasonal foci where transmission is known to be seasonal.
- Community engagement: in addition to being a critical component of the SCP model, it is especially important in these regions for community engagement and education to be successful to achieve it.
Key Considerations for Implementing SCP Worldwide
1. Adapting to Local Contexts
Successful implementation of SCP requires adapting the strategy to local contexts, including:
- Local patterns: Learn about what the malaria transmission patterns are locally (seasonal? highest during the rainy season?) and how this information can be used to design an effective SCP program.
- Second, it is important to ensure that there is good monitoring of drug resistance, and that suitable antimalarial drugs are used.
- Healthcare infrastructure: we need solid healthcare infrastructure and logistical networks to dispense and treat drugs.
2. Ensuring High Coverage and Adherence
High coverage and adherence are essential for the SCP to successfully reduce infections and mortality. Several strategies exist for maximizing coverage and adherence:
Ensuring participation is key to the success of SCP, which is why it’s beneficial to engage with people and communities at an early stage in the planning and implementation of SCP programs. This collaboration should continue throughout the program, as communities can provide valuable information about which sustainable foods are popular and appreciated. By engaging with these communities, hunting programs can reduce the risk of resource loss and ensure that communities continue to enjoy significant benefits from their participation. At a social level, trust has always been important for maintaining effective hunting programs, but it has recently become of paramount importance.
Monitoring and evaluation Regular monitoring and evaluation are important to track and evaluate the extent of the impact of SCP and to adjust the intervention based on these findings.
3. Addressing Challenges and Barriers
Implementing SCP worldwide involves addressing various challenges, including:
- Resource Constraints: SCP programs’ success is contingent on ensuring sufficient financial and other resources.
- Political and Social: Political upheaval, social issues, and other reasons can create barriers to the implementation of SCP. We can again build partnerships and advocate for support.
- Ongoing efforts for identifying drug resistance and monitoring anti-malarial drug efficacy are important for the success of SCP.
Future Directions and Research
1. Research on New Drugs and Strategies
The search for new antimalarial drugs and ways of strengthening SCP goes on. We still need to find tolerable combination therapies, for instance, and perhaps drugs that deliver quicker results. We must circumvent resistance.
2. Expanding Geographical Scope
3. Integration with Broader Malaria Control Efforts
Moreover, combining SCP with other malaria control interventions such as vector control and health education can improve the effectiveness of these efforts and bring us closer to malaria eradication.
Thus, SCP has been primarily deployed in settings with highly seasonal transmission, applied during the dry rather than wet season to further reduce the eventuality of malaria cases. Over the past two decades, the evidence from SCP’s applications in Africa has shown that, notably, SCP can act as a key tool in reducing the malaria burden and, furthermore, improving the health of individuals. As the global landscape of malaria evolves, examining the potential for deploying SCP where it has not been tried before – in nonseasonal malaria transmission areas – seems like a promising avenue for scaling up and improving malaria control globally. By leveraging local contexts and evidence, adapting SCP strategies to them, tackling the challenges that arise, and investing in the research needed, stakeholders could soon make notable gains in the global fight against malaria.
