Paediatric iGAS Morbidity and Mortality in Ireland 2022-2023 episodic upsurge

Abstract There was an unseasonal upsurge in invasive Group A Streptococcal (iGAS) activity in Ireland during the 2022/2023 winter period. In particular, there was an increase in the proportion of paediatric infections and a rise in the age specific death rate for those under the age of 18, from 0.10 to 1.43 per 100,000. This review aimed to describe the demographic and clinical factors associated with paediatric iGAS infection during this upsurge. All iGAS cases under the age of 16 years, notified to Public Health between 1st October and 30th June 2023, were included. A review of hospital records for each case was conducted using a standardised electronic data collection proforma. Descriptive, univariate and multivariate analysis was conducted using SPSS statistical package. There was a total of 183 cases of iGAS notified during this upsurge in Ireland. A hospital chart review was conducted for 169 of these cases, giving a response rate of 92.3%. The median age was 4 years (range 0-15,) with 44.4% (75) having a previous healthcare attendance during their illness. Varicella coinfection occurred in 27.8% (47) of cases. There was respiratory viral coinfection in 40.8% (69) of cases, and this was significantly associated with an increased risk of death RR 6.49 (95% CI 4.45 - 29.08) p < 0.05. A respiratory site of infection was also significantly associated with an increased risk of death RR 10.13 (95% CI 2.23 - 45.95) p < 0.001. However, both factors did not remain significant once adjusted for age, sex, ethnicity and deprivation index. This national review demonstrated the significant burden of paediatric iGAS morbidity and mortality during this upsurge. A significant proportion of cases, 37.9% (64) were associated with vaccine preventable illness, with respiratory viral infections and a respiratory site of infection both being significantly associated with an increased risk of death. Key messages • A significant proportion of iGAS cases were associated with a vaccine preventable illness. • A respiratory site of iGAS infection was significantly associated with an increased risk of death in paediatric cases.