Malaria: Examining Persistence at the Margins of Endemicity over 15 Years in Saudi Arabia

<i>Background and Objectives</i>: Malaria, a mosquito-borne parasitic disease caused by <i>Plasmodium</i> species, remains a public health concern in many tropical and subtropical regions. In Saudi Arabia, sustained control efforts have substantially reduced malaria transmission; however, regional heterogeneity and the growing contribution of imported infections continue to shape national malaria epidemiology. This study aimed to provide a comprehensive national assessment of malaria patterns in Saudi Arabia within a prevention-of-reintroduction framework. <i>Materials and Methods</i>: National malaria surveillance data reported by the Ministry of Health from 2010 to 2024 were analyzed to describe temporal trends in malaria burden and incidence, parasite species distribution, age structure, and seasonality across 20 health regions. Spatial heterogeneity was assessed using regional heatmaps and endemicity mapping. Transmission classification, parasite species, and age distribution were examined nationally and in greater detail for the Aseer and Jazan regions during 2021-2024. Future malaria trends through 2030 were projected using autoregressive integrated moving average (ARIMA) models. <i>Results</i>: Between 2010 and 2024, a total of 52,627 malaria cases were reported nationally, with marked interannual variability and an increase in incidence observed after 2020. Malaria burden was historically concentrated in seven endemic regions and subsequently became largely restricted to Aseer and Jazan. <i>Plasmodium falciparum</i> and <i>Plasmodium vivax</i>/<i>Plasmodium ovale</i> accounted for the majority of infections, with cases predominantly occurring among individuals aged ≥10 years. From 2021 onward, no indigenous malaria transmission was recorded; introduced cases were uncommon, and most infections were classified as imported. Forecasting analyses indicated stable national and regional malaria trends through 2030. <i>Conclusions</i>: Malaria in Saudi Arabia during 2010-2024 was characterized by pronounced regional heterogeneity and predominantly importation-driven dynamics. These findings underscore the importance of sustained surveillance, targeted interventions in high-burden regions, and continued vigilance to prevent the re-establishment of local transmission.