Defining the role of primaquine in malaria elimination.

A single drug, primaquine, is the only treatment that can stop the transmission of the most dangerous malaria parasite and cure the two relapsing forms of the disease—yet it sits on the shelf because doctors are not sure how to use it safely. The problem is that primaquine can destroy red blood cells in people with a common genetic condition called G6PD deficiency, and no one has settled on the right dose for different patients. Researchers in Thailand will run a series of clinical and pharmacological studies to pin down the drug’s safety profile, its effectiveness against relapsing *P. vivax* malaria, and how it behaves in adults and children. They will also develop simple bedside tests to predict who is at risk of haemolysis. If this work succeeds, elimination programmes in Southeast Asia and beyond will finally have a clear, evidence-based dosing regimen for primaquine. That could allow health systems to deploy the drug widely, cutting transmission chains and reducing the reservoir of relapsing infections that keep malaria endemic in many regions. The research is directly practical: it aims to remove the uncertainty that currently blocks a cheap, existing tool from being used at scale.