Examining the Malaria Burden: Estimates of Repeat Malaria Cases in Select Counties in the Lake Endemic Region, Kenya, June 2021-May 2022

Background According to the 2020 malaria indicator survey, in Kenya, the prevalence of malaria in children aged 6 months to 14 years was 6%, with the highest prevalence in Busia at 38.5%, followed by Siaya at 28.8%, and Kisumu at 15.6%. Repeat malaria cases are infections confirmed by lab tests that occur after seven days of treatment. However, there is limited information on the prevalence of repeat cases. Thus, this study aims to examine the characteristics of repeat cases in select hospitals in Busia, Kisumu, and Siaya, with high incidence rates. Methods We conducted retrospective record reviews in several hospitals in Busia, Kisumu, and Siaya, which were selected based on their high incidence rates. We extracted patient data from outpatient, laboratory, and inpatient registers into MS Excel, including the date of visit, age, sex, residence, and malaria tests. We analyzed categorical data using frequencies and percentages and continuous variables using the median and interquartile range. Results In this study, there were 26,133 cases, out of which 3,136 (12%; 95% CI, 11.6–12.4) were repeat cases. Children under 15 years accounted for 64% (1,993) of the repeat cases, with females making up 58% (1,833), and Busia contributing 72% (n = 2,249). Urban and peri-urban facilities contributed 44% (1,333) and 42% (1,275) of repeat cases, respectively. Microscopy diagnosed 22% (687) of repeat cases in both the first and second episodes, while mRDT diagnosed 43% (1,335) in both episodes. Of those diagnosed with mRDT in both episodes, 80.8% (1,079) exceeded the 42-day interval between tests. The laboratory testing compliance with national malaria diagnosis, testing, and treatment guidelines was 88% for first repeat cases. Children under 5 years were 1.5 times more likely to undergo laboratory testing according to national guidelines than those aged 5–14 years. The use of microscopy versus rapid test in the first repeat episode was strongly associated with patients' age (ꭓ28.2, p = 0.004). The median interval between the first and second malaria episodes was 146 days (IQR, 51–341). Conclusion Repeat malaria cases represented 12% of the total, depicting similar distribution in person and place. The majority of these cases were contributed by females and children below 15 years. However, the actual burden of these cases could be greater as lower-level healthcare facilities were not investigated. To curb repeat malaria infections in children, the malaria lake-endemic counties should enhance laboratory surveillance and treatment