Throat carrier rates of beta-hemolytic streptococci among healthy adults and children.

In order to investigate the carrier rate of beta-hemolytic streptococci throat cultures were obtained every third month from 382 asymptomatic adults and schoolchildren during a 2-year period, altogether 2226 samples. In addition, 300 asymptomatic 4-year-olds were sampled once. The carrier rate of beta-hemolytic streptococci was 19.4%; group A streptococci alone 5.0%. There was no season-dependent variation. In the 3 age groups the carrier rates of group A streptococci were 0.8%, 5.9%, and 11.3%, respectively, with the highest rate among the 4-year-olds. Some of the individuals that were sampled repeatedly seemed to be pharyngeal carriers of group A streptococci, while others never became carriers. Group A streptococci were found significantly more often among 4-year-olds not attending day-care centres compared to those attending such institutions. For group C and G streptococci the influence of age on carrier rates was not similar to that found for group A streptococci. Throat carriership of beta-hemolytic streptococci does not result in clinical infections.