Malaria trends in districts that were targeted and not-targeted for seasonal malaria chemoprevention in children under 5 years of age in Guinea, 2014-2021

Abstract

Background: Seasonal malaria chemoprevention (SMC) is a main intervention 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 or had not been targeted for SMC.

Methods: Using routine health management information system data, we compared the district-level monthly test positivity rate (TPR) and monthly uncomplicated and severe malaria incidence for the whole population and disaggregated age groups (<5 years and ≥5 years of age). Changes in malaria indicators through time were analysed by calculating the district-level compound annual growth rate (CAGR) from 2014 to 2021; we used statistical analyses to describe trends in tested clinical cases, TPR, uncomplicated malaria incidence and severe malaria incidence.

Results: The CAGR of TPR of all age groups was statistically lower in SMC (median=-7.8%) compared with non-SMC (median=-3.0%) districts. Similarly, the CAGR in uncomplicated malaria incidence was significantly lower in SMC (median=1.8%) compared with non-SMC (median=11.5%) districts. For both TPR and uncomplicated malaria incidence, the observed difference was also significant when 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%) than in non-SMC (median=-5.1%) districts for the entire population, as well as both CU5 and people over 5 years of age.

Conclusion: Even in an operational programming context, adding SMC to the malaria intervention package yields a positive epidemiological impact and results in a greater reduction in TPR, as well as the incidence of uncomplicated and severe malaria in CU5.

Keywords: Control strategies; Malaria; Prevention strategies; Public Health.

Figure 1

Districts covered by the StopPalu and StopPalu+ in which SMC was performed. Image creator/owner: DB. SMC, seasonal malaria chemoprevention.

Figure 2

CAGR of tested fevers (A), TPR (B), uncomplicated malaria incidence (C), and severe malaria incidence (D) in SMC districts and non-SMC districts from 2014 to 2021. The ‘*’ symbol represents a significant difference (p<0.05, Wilcoxon’s test) between CAGR values of SMC district and non-SMC districts. Image creator/owner: DB. CAGR, compound annual growth rate; SMC, seasonal malaria chemoprevention; TPR, test positivity rate.

Figure 3

Boxplot comparing TPR of SMC (left column) and non-SMC (right column) districts by age group of 2014 to November 2021 for <5 years and ≥5 years age group. The ‘*’ symbol represents a significant difference (p<0.05, Wilcoxon’s test) between SMC and non-SMC districts. Image creator/owner: DB. SMC, seasonal malaria chemoprevention; TPR, test positivity rate.

Figure 4

Boxplot comparing uncomplicated malaria incidence of SMC (left column) and non-SMC (right column) districts per age group of 2014 to April 2019 for <5 years age group and ≥5 years age group. The ‘*’ symbol represents a significant difference (p<0.05, Wilcoxon’s test) between SMC and non-SMC districts. Image creator/owner: DB. SMC, seasonal malaria chemoprevention.

Figure 5

Boxplot comparing severe malaria cases per 1000 people in SMC (left column) and non-SMC (right column) districts per age group of 2014 to April 2019 <5 yrs age group and ≥5 years age group. The ‘*’ symbol represents a significant difference (p<0.05, Wilcoxon’s test) between SMC district and non-SMC districts. Image creator/owner: DB. SMC, seasonal malaria chemoprevention.