RESUMEN
Two studies were conduct in Thailand in order to find appropriate falciparum malaria prophylactic drug regimens. The first study was done during June - September 1987 with 363 soldiers who received Fansimef (MSP) 1 tab/week (group 1), 337 soldiers who received MSP 1 tab/2 week (group 2) and 165 soldiers who received chloroquine 300 mg base weekly plus Fansidar 1 tab/week (group 3). At the end of the study there were 9 and 13 falciparum malaria episodes in groups 1 and 2, respectively, with incidence rates of 0.8 and 1.8 cases/100 person-months (P-M). In group 3, the corresponding values were 30 episodes and an incidence of 7.2/100 P-M. For the second study which lasted from October 1987 - January 1988 in the same area, 498 soldiers were given Fansimef 1/2 tab/week (group 4), 499 soldiers were given Lariam 1/2 tab/week (group 5) and 247 soldiers were given chloroquine plus Fansidar (group 6). Thirty malaria episodes were found in group 4, for an incidence of 2.0/100 P-M. In group 5, 23 episodes were found, for an incidence of 1.6/100 P-M. In group 6, 74 episodes occurred, ie an incidence of 12.2/100 P-M. The incidence rates of malaria among Fansimef 1 tab weekly, Fansimef half dose weekly or Lariam half dose weekly were not significantly different but were different from chloroquine plus Fansidar groups. Adverse events in each group were mild.