A clinical trial of malaria prophylaxis using a single dose of chloroquine at different intervals in an endemic malarious area.

A controlled trial of chloroquine prophylaxis was carried out to find whether this drug could be administered at intervals longer than the conventional ones recommended, in endemic malarious areas. Statistically significant results obtained show that chloroquine at suitable doses could be used successfully at intervals of 3 months. The possibility of chloroquine and acquired immunity acting together synergistically is discussed. The author is of the opinion that with this dose regime, the community would still be able to build up substantial immunity, so that in the event of the drug being discontinued, the community would not be faced with the problem of overwhelming malarial infections. The various advantages in using this regime are also considered.