However, most of these antimalarial treatments could not be considered effective since: (i) 95% were with chloroquine, against which there is a high rate of falciparum malaria resistance; (ii) a significant proportion were not started within 24 hours of the onset of fever, so not all treatments were necessarily given in sufficient time to prevent a possible progression into severe life-threatening malaria; and (iii) the dosages typically taken might not always have been adequate for full parasitological cure, although dosaging was not measured in national surveys. For these reasons, the coverage with prompt and effective antimalarial treatment was probably much lower than survey data indicate. However, it is likely that the proportion of fevers treated with effective antimalarial regimens is now increasing in those countries that have recently implemented a change in drug policy to combination treatment.