Malaria trends in districts that were targeted and not-targeted for seasonal malaria chemoprevention in children under five years of age in Guinea, 2014–2021

Background Seasonal malaria chemoprevention (SMC) is one of the main interventions recommended by WHO to prevent and reduce childhood malaria. Since 2015, Guinea has implemented SMC targeting children aged 3–59 months (CU5) in districts with high and seasonal malaria transmission. Objective We assessed the programmatic impact of SMC in Guinea’s context of scaled-up malaria intervention programming by comparing malaria-related outcomes in 14 districts that had (n = 8) or had not (n = 6) been targeted for SMC. Method Using routine health management information system data, we calculated the district-level monthly test positivity rate (TPR) and monthly uncomplicated and severe malaria incidence for the whole population and disaggregated age groups (<5yrs and ≥5yrs of age). Changes in malaria indicators through time were analyzed by calculating the district-level compound annual growth rate (CAGR) from 2014 to 2021; we used statistical analyses to describe the time trend of the number of tested clinical cases, TPR, uncomplicated malaria incidence, and severe malaria incidence. Result The CAGR of TPR of all age groups was statistically lower in SMC (median = −7.8%, range [IQR] = −9.7%, −5.5%) compared to non-SMC (median = −3.0%, IQR = −3.0%, −1.2%) districts. Similarly, the CAGR in uncomplicated malaria incidence was significantly lower in SMC (median = 1.8%, IQR = −0.9%, 3.5%) compared to non-SMC (median = 11.5%, IQR = 8.8%, 14.0%) districts. For both TPR and uncomplicated malaria incidence the observed difference was also significant age disaggregated. The CAGR of severe malaria incidence showed that all age groups experienced a decline in severe malaria in both SMC and non-SMC districts. However, this decline was significantly higher in SMC (median = −22.3%, IQR= −27.6%, −18.2%) than in non-SMC (median = −5.1%, IQR= - 7.7; −3.6) districts for the entire population, as well as both CU5 and people over 5 years of age. Conclusion Our results provide evidence to support that—even in an operational programming context—adding SMC to the comprehensive package of malaria interventions yields a positive epidemiological impact and results in greater reduction in TPR, as well as the incidence of uncomplicated and severe malaria in CU5. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Financial support for this study was provided by the U.S. President's Malaria Initiative through the U.S. Agency for International Development StopPalu (Cooperative Agreement Number: AID-675-A-13-00005) and StopPalu+ (Cooperative Agreement Number: 72067518CA000015) programs. The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the U.S. Agency for International Development. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study only used existing (secondary) data that were collected for public health planning and programming purposes. The data were only available and analyzed at the aggregate level and thus ethical approval for the analyses was not necessary a priori. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors