2.8.3. Rescue treatment - A recurrent vivax parasitaemia within 28 days is potentially a recrudescent infection. These patients would be re-treated with the standard CQ-PQ co-administration regimen and remain in the study. After 28 days, a recurrent vivax parasitaemia is more likely a relapse or a new infection. These patients would be treated with the standard CQ-PQ co-administration regimen. Patients who develop severe malaria would be admitted to hospital and treated according to the guidelines of the Ministry of Health of Brazil.