Wellcome Open Research (Jan 2024)

Two decades of malaria control in Malawi: Geostatistical Analysis of the changing malaria prevalence from 2000-2022 [version 2; peer review: 1 approved, 3 approved with reservations]

  • Tapiwa Ntwere,
  • Atupele Kapito-Tembo,
  • Halima Twabi,
  • Esloyn Musa,
  • Don P. Mathanga,
  • Nyanyiwe Masingi-Mbeye,
  • Lumbani Munthali,
  • Maclear Masambuka,
  • Abdoulaye Bangoura,
  • Melody Sakala,
  • Michael Give Chipeta,
  • Dianne J Terlouw,
  • Chimwemwe Ligomba,
  • Austin Gumbo,
  • James Chirombo,
  • Donnie Mategula,
  • Judy Gichuki,
  • Michael Kayange,
  • Benard Banda,
  • Jacob Kawonga,
  • Patrick Ken Kalonde,
  • Alinafe Kalanga,
  • Gracious Hamuza,
  • Colins Kwizombe,
  • Jacob Kafulafula,
  • Vincent Samuel,
  • Colins Mitambo,
  • Dina Kamowa,
  • Akuzike Banda

Journal volume & issue
Vol. 8

Abstract

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Background Malaria remains a public health problem in Malawi and has a serious socio-economic impact on the population. In the past two decades, available malaria control measures have been substantially scaled up, such as insecticide-treated bed nets, artemisinin-based combination therapies, and, more recently, the introduction of the malaria vaccine, the RTS,S/AS01. In this paper, we describe the epidemiology of malaria for the last two decades to understand the past transmission and set the scene for the elimination agenda. Methods A collation of parasite prevalence surveys conducted between the years 2000 and 2022 was done. A spatio-temporal geostatistical model was fitted to predict the yearly malaria risk for children aged 2–10 years (PfPR 2–10) at 1×1 km spatial resolutions. Parameter estimation was done using the Monte Carlo maximum likelihood method. District-level prevalence estimates adjusted for population are calculated for the years 2000 to 2022. Results A total of 2,595 sampled unique locations from 2000 to 2022 were identified through the data collation exercise. This represents 70,565 individuals that were sampled in the period. In general, the PfPR2_10 declined over the 22 years. The mean modelled national PfPR2_10 in 2000 was 43.93 % (95% CI:17.9 to 73.8%) and declined to 19.2% (95%CI 7.49 to 37.0%) in 2022. The smoothened estimates of PfPR2_10 indicate that malaria prevalence is very heterogeneous with hotspot areas concentrated on the southern shores of Lake Malawi and the country's central region. Conclusions The last two decades are associated with a decline in malaria prevalence, highly likely associated with the scale-up of control interventions. The country should move towards targeted malaria control approaches informed by surveillance data.

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