Therapeutic efficacy, safety and gametocyte clearance after antimalarial treatment of uncomplicated Plasmodium falciparum and Plasmodium vivax malaria in Northeast Ethiopia.

Malaria remains a major public health challenge in Ethiopia, with Plasmodium falciparum and Plasmodium vivax accounting for most malaria cases. Continuous monitoring of antimalarial drug efficacy and safety is essential to ensure effective case management and to detect early signs of emerging drug resistance. In addition, understanding gametocyte clearance following treatment is important because persistent gametocytaemia can sustain malaria transmission. This study assessed the therapeutic efficacy, safety, and gametocyte clearance following antimalarial treatment among patients with uncomplicated P. falciparum and P. vivax malaria in Northeast Ethiopia. A prospective observational study was conducted from November 2024 to January 2026 among 159 patients with uncomplicated malaria, including 81 P. falciparum and 78 P. vivax infections. Patients received treatment according to national guidelines, with artemether-lumefantrine for P. falciparum and chloroquine for P. vivax, while a subset also received a single low dose of primaquine. Participants were followed for 28 days to assess therapeutic outcomes, fever clearance, asexual parasite clearance, haemoglobin recovery, gametocyte clearance and adverse events. Data were analysed using SPSS version 26.0. Kaplan-Meier survival analysis was used to evaluate fever, parasite, and gametocyte clearance. Statistical significance was considered at p < 0.05. Therapeutic efficacy was high in both species, with adequate clinical and parasitological response rates of 88.9% among P. falciparum patients and 97.4% among P. vivax patients. Fever and asexual parasite clearance occurred more rapidly in P. vivax than in P. falciparum, with median fever clearance times of 2 and 3 days and median parasite clearance times of 2 and 4 days, respectively. Haemoglobin levels improved throughout follow-up in both groups, although P. falciparum infections were associated with lower baseline haemoglobin levels. Antimalarial treatments were generally well tolerated, with most adverse events being mild and no treatment discontinuations recorded. A transient increase in gametocyte carriage on day 3 was observed more frequently among participants who did not receive primaquine. Primaquine significantly accelerated gametocyte clearance, reducing the median clearance time from 11 to 7 days in P. falciparum and from 7 to 4 days in P. vivax. Higher baseline gametocyte density was associated with slower gametocyte clearance, particularly among P. falciparum patients. First-line antimalarial treatments remain highly effective and well tolerated for the management of uncomplicated P. falciparum and P. vivax malaria in Northeast Ethiopia. However, post-treatment gametocyte persistence may contribute to ongoing transmission, particularly in P. falciparum infections. The addition of low-dose primaquine significantly enhanced gametocyte clearance in both species, highlighting its potential role in reducing transmission and supporting malaria elimination efforts.