Efficacy of Focal Primaquine Mass Administration for Eliminating Malaria in Northern Myanmar: A Cluster-Randomized Trial.

BACKGROUND

poses a major challenge for malaria elimination, primarily because of relapse. Primaquine mass drug administration (PQ-MDA) has played a decisive role in eliminating vivax malaria in many temperate countries, but its efficacy in tropical/subtropical areas remains underexplored.

METHODS

We conducted a cluster-randomized crossover trial to determine the effect of PQ-MDA on transmission in northern Myanmar, a subtropical area in the Greater Mekong subregion with perennial malaria transmission. Participants from two groups of villages (groups 1 and 2) were administered 0.25 mg/kg/day PQ base for 14 days as directly observed therapy. During PQ-MDA administration, each group alternated as the control while the other received the intervention, with the groups switching after 9 months. Clinical malaria incidence and prevalence were monitored to determine the efficacy.

RESULTS

PQ was administered in 541 participants in group 1 and 667 in group 2 during August-September 2019 and June-July 2020, respectively. In both groups, clinical incidence sharply declined to zero within a month of PQ-MDA and remained vivax-free for almost a year. During round 1 PQ-MDA, group 1 with MDA had a significant reduction in the prevalence of subclinical compared to group 2 as the control, with a model-adjusted odds ratio (aOR) of 0.46 [95% confidence interval (CI): 0.25-0.83]. During round 2, group 2 exhibited an even lower aOR of 0.15 (95% CI: 0.03-0.65) for subclinical infection.

CONCLUSIONS

PQ-MDA was effective in reducing both clinical and subclinical infections in a subtropical, low-endemicity setting.

CLINICALTRIALSREGISTRATION

This study was registered with ClinicalTrials.gov (NCT06392152).