Evaluation of an Alaskan streptococcal control program: importance of the program's intensity and duration

Prospective follow-up information from the throat culturing results of 1,653 Eskimo children in 12 Alaskan villages was used to evaluate the effect of duration and intensity of a streptococcal control program begun in 1971 while controlling for several other risk factors related to streptococcal colonization. Relative risks of colonization for each of the subsequent study years relative to the first year indicate that the risk of colonization decreased over the duration of the study by 42% in Year 2 to 55% in Year 4 (P less than 0.0001). Cost-cutting measures such as lengthening the time interval between routine throat cultures led to a 37% increase in the risk of colonization (P = 0.0002). A comparison of the number of cases of acute rheumatic fever during the 5-year period before the streptococcal control program with the number of cases during the 5-year program period showed that cases in villages with the program decreased from 11 to 0. In a similar group of comparison villages without the program, the number of cases decreased from 7 to 4. A benefit-cost study of the program indicates that benefit exceeds cost. These findings and the changes in the carriage of streptococcal organisms during the control program underscore the importance of such long-term programs with regularly scheduled culturing in high-risk populations of children.