Clinical and Microbiological Characteristics of Invasive Group A Streptococcal Infections Before and After Implementation of a Universal Varicella Vaccine Program.

Since the introduction of the varicella vaccine to the routine immunization schedule, we have observed a 70% reduction in the rate of varicella-associated invasive group A streptococcal infections (IGASI). In the mean time, the clinical presentation of IGASI and microbiological characteristics of GAS strains have changed significantly.