Household costs associated with zoonotic Plasmodium knowlesi , P. falciparum , P. vivax and P. malariae infections in Sabah, Malaysia

Background: Malaysia has free universal access to malaria care; however, out-of-pocket costs are unknown. This study estimated and compared household costs of illness during a unique time when four species of malaria were present, due to the emergence of zoonotic Plasmodium knowlesi during the elimination phase of non-zoonotic species in Sabah, Malaysia. Methodology/principal findings: Household costs were estimated from patient-level surveys collected from four hospitals between 2013 and 2016. Direct costs including medical and associated travel costs, and indirect costs due to lost productivity were included. One hundred and fifty-two malaria cases were enrolled: P. knowlesi (n=108), P. vivax (n=22), P. falciparum (n=16), and P. malariae (n=6). Costs were inflated to 2023 Malaysian Ringgits and reported in United States dollars (US$). Across all cases, the mean total costs were US$131 (SD=102), with productivity losses accounting for 58% of costs (US$76; SD=70). P. vivax had the highest mean total household cost at US$199 (SD=174), followed by P. knowlesi and P. falciparum at US$119 (SD=81 and SD=83, respectively), and P. malariae (US$99; SD=42). Most patients (80%) experienced direct health costs above 10% of monthly income, with 58 (38%) patients experiencing health spending over 25% of monthly income, consistent with catastrophic health expenditure. Conclusions/significance: Despite Malaysia’s free health-system care for malaria, patients and families face other related medical, travel, and indirect costs. Household out-of-pocket costs were driven by productivity losses; primarily attributed to infections in working-aged males in rural agricultural-based occupations. Costs for P. vivax were higher than those of P. knowlesi and P. falciparum. This may be attributable to a younger age profile and the longer treatment required to clear the liver-stage parasites of P. vivax. Author summary: Malaria patients experience financial barriers when seeking care, despite free access to universal care in Malaysia. In some areas of Southeast Asia, multiple species of malaria can be present within the same setting, including recently emerged knowlesi malaria, which is spread from monkeys to humans via mosquitos. The economic burden of illness due to multiple species of malaria has not previously been estimated in the same setting. We collected data on the cost of illness to households in Sabah, Malaysia, to estimate their related total economic burden during the elimination phase of human-only malaria. Medical costs and time off work and usual activities were substantial in patients with the four species of malaria diagnosed during the time of this study. This research highlights the financial burden which households face when seeking care for malaria in Malaysia, despite the free treatment provided by the government.