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Suboptimal primaquine adherence in Plasmodium vivax malaria: Evidence from high-burden tribal districts in Odisha

Year: 2025

Type: article

Abstract: BACKGROUND: Eliminating Plasmodium vivax malaria in India's tribal regions is challenging, mainly due to poor adherence to primaquine, the only hypnozoiticidal drug for radical cure under national policy. Incomplete adherence to the 14-day primaquine regimen leads to relapse, treatment failure, ongoing transmission, and may contribute to antimalarial resistance. This study quantified primaquine adherence, and explored behavioral factors influencing non-adherence in high-burden tribal districts of Odisha. METHODS: This prospective cohort study conducted from January to December 2024 in two high-burden tribal districts (Malkangiri, Koraput) enrolled 269 laboratory-confirmed P. vivax patients aged over one year. Structured questionnaires collected demographic, clinical, and treatment data. Adherence to the 14-day primaquine regimen was assessed on days 7 and 14 via self-report, pill counts, and blister pack inspection. Uni- and multivariable analyses identified predictors of non-adherence. RESULTS: Adherence to chloroquine (3 days) and artesunate-SP (mixed infections) exceeded 93 %, while only 58.7 % (95 % CI: 52.6-64.9) completed the 14-day primaquine course. Healthcare workers dispensed drugs according to guidelines. Treatment discontinuation was mainly due to symptom resolution (61.9 %) and forgetfulness (21.4 %); only one patient discontinued primaquine due to an adverse event. Older age and household malaria history were associated with better adherence. CONCLUSION: Suboptimal primaquine adherence delays P. vivax elimination despite adequate drug supply and correct dosing. Addressing behavioral drivers of early treatment cessation is critical to interrupt relapse transmission. Programmatic focus should include intensified social behavior change communication, targeted directly observed therapy, and evaluation of shorter primaquine or single-dose tafenoquine treatments with G6PD testing to enhance radical cure and accelerate India's 2030 malaria elimination goal.

Source: Journal of Infection and Public Health

DOI: 10.1016/j.jiph.2025.103123