My son is now 29. When he was 6 he kept getting strep throat. Each time he finished all of his antibiotic. Finally the pediatrician tested everyone. My son was the carrier. He could be tested at any given time and would be positive for strep but would not sick. To top it off, he was allergic to penicillin and all related to penicillin. The antibiotic was sooooooo expensive. He has to wear a bracelet at all times. This is the same child who had Mononucleosis at age 4. It took about 6 weeks for him to totally recover.