A Cluster of Pediatric Invasive Group A Streptococcus Disease in Melbourne, Australia, Coinciding with a High-Burden Influenza Season

Background Invasive group A streptococcal disease (IGAS) carries significant morbidity and mortality in children. Fluctuations in disease incidence are well documented. However, the modulating factors that contribute to these changes remain unclear. Prospective monitoring of IGAS cases in Victoria, Australia, showed an increased number of cases in 2017, coinciding with a peak of influenza illness. Methods Children identified to have IGAS are prospectively monitored in Melbourne through a disease surveillance network. Data on their presentation, investigations, and clinical course are collected. An increased number of cases identified between June 1, 2017, and October 31, 2017, have been retrospectively analyzed. Results We identified 22 cases of pediatric IGAS during the study period. Increased case detection occurred during a period of increased influenza disease. Of 11 children in our cohort who underwent respiratory viral testing, 4 were confirmed to have concurrent respiratory tract illnesses, and 2 were confirmed to have influenza.