Efficacy of chloroquine with primaquine for uncomplicated Plasmodium vivax malaria without G6PD testing in Northwest Ethiopia: a one-arm in vivo prospective therapeutic efficacy study

Abstract Background The declining efficacy and widespread resistance to antimalarial drugs (AMD) pose significant challenges to global malaria control and elimination efforts. To enhance treatment efficacy, the World Health Organization (WHO) recommends the use of combination therapies. This study aimed to evaluate the therapeutic efficacy of chloroquine with primaquine (CQ–PQ) for the treatment of uncomplicated Plasmodium vivax malaria in the study area. Methods The study utilized a single-arm, 42-day follow-up design to assess the therapeutic efficacy and safety of a treatment regimen in Northwest Ethiopia. Participants, all diagnosed with uncomplicated vivax malaria, received a 3-day course of chloroquine (CQ) at 25 mg/kg, followed by a 14-day course of primaquine (PQ) at 0.25 mg/kg. Participants were monitored with follow-up visits on days 1, 2, 3, 7, 14, 21, 28, 35, and 42. Data were double-entered into a standard Excel sheet by the WHO and analysed using SPSS v.26. Statistical analyses included Kaplan–Meier survival analysis, t-tests, and ANOVA, with statistical significance set at p