This is a randomised open label trial with follow up for 1 year. 660 adults and children
above 6 months diagnosed with acute Plasmodium vivax will be randomised into 3 groups, either
chloroquine, artesunate, or chloroquine/primaquine therapy. Participants will be screened on
the day of inclusion then followed weekly for 8 visits and every 4 weeks until week 52. The
primary objective of the study is to compare the efficacy of the WHO and Thai Ministry of
Public Health recommended radical curative regimen of chloroquine and primaquine with the
currently used monotherapy regimens of chloroquine and artesunate along the Thai-Burmese
border.