Don't recommend Doxycycline at all. I took it for over a year in Mozambique, and ended up getting Vivax malaria. It ended up masking the symtoms, while the Malaria stayed in the liver. From now on I just try cover up, and coat exposed areas with Tabbard. You soon know if you have Malaria (headaches then blurred vision etc), then just take a dose of Coartem.