419 - Resurgence of Pediatric Invasive Group A Streptococcus Infections Following the COVID-19 Pandemic: A Tertiary-Care Experience

Publication Number: 2407.419

Giordano J. Sosa Soto, Boston Children's Hospital, Boston, MA, United States; Philip D. Chen, Boston Children's Hospital, Cambridge, MA, United States; Soumyaa Mazumder, Boston Children's Hospital, Boston, MA, United States; C. Abigail. Temple, Boston Children's Hospital, Boston, MA, United States; Brenda Kashi, Boston Children's Hospital, Boston, MA, United States; Michael Wessels, Boston Children's Hospital, Boston, MA, United States; Mari M. Nakamura, Boston Children's Hospital, Boston, MA, United States; Kristin Moffitt, Boston Children's Hospital, Boston, MA, United States

Background: Invasive group A Streptococcus (iGAS) infections cause significant morbidity and mortality among children worldwide. During the COVID-19 pandemic, respiratory infections declined sharply in association with public health measures, followed by a resurgence post-pandemic. We assessed whether iGAS showed a similar pattern.

Objective: To compare the incidence, clinical characteristics, and outcomes of pediatric iGAS infections across the pre-, peri-, and post-pandemic periods.

Design/Methods: Retrospective cohort study of hospitalized patients aged < 18 years with iGAS infections at a tertiary children's hospital, identified via microbiological data and diagnostic codes, stratified into pre- (Jan 2018-Feb 2020), peri- (Mar 2020-Aug 2022), and post-pandemic (Sep 2022-Jun 2024) periods. We statistically compared the pre- and post-pandemic periods. Incidence was compared using incidence rate ratios relative to the pre-pandemic period.

Results: We identified 218 iGAS cases: 82 pre-, 19 peri-, and 117 post-pandemic. From pre- to peri-pandemic, the incidence dropped from 6.2 to 1.23 per 100,000 patient-days (IRR 0.2; 95% CI 0.12-0.33); post-pandemic, it surged to 9.3 per 100,000 patient-days (IRR 1.50; 95% CI 0.92-2.43). Demographics, comorbidities, and ICU admission rates were similar across periods. Fever and cough were the most common symptoms, and laboratory values (WBC, ANC, CRP, procalcitonin) showed no significant differences. Clinical syndromes shifted from pre- to post-pandemic, with fewer pyomyositis/soft-tissue infections (p < 0.001) and more multifocal disease (p < 0.05); surgery was required in 58%-63% of cases. Clindamycin use declined (44% to 19%, p< 0.001), while linezolid use increased (10% to 21%, p< 0.05). Respiratory support use was stable, while ECMO use (≤3%) was low throughout. The median hospital stay was steady at 4-5.5 days. All deaths occurred post-pandemic, but mortality was low (4/117, 3.4%).

Conclusion(s): iGAS incidence markedly declined during the pandemic and rebounded afterward, perhaps reflecting the effects of public health measures on transmission. Non-significant trends toward increased incidence and an older median age in the post-pandemic period may reflect reduced immunity acquisition through exposure during the pandemic. Severity and outcomes were unchanged across periods, despite all deaths occurring in the post-pandemic period. Continued surveillance is warranted to track evolving epidemiologic patterns.

Table 1. Incidence of Pediatric Invasive Group A Streptococcus Infections per 100,000 Patient Days Across Pre-, Peri-, and Post-Pandemic Periods
Pre-pandemic defined as Jan 2018-Feb 2020, peri-pandemic as Mar 2020-Aug 2022, and post-pandemic as Sep 2022-Jun 2024. Confidence intervals (CI) for incidence rate ratios (IRR) relative to the prepandemic period were calculated using the Poisson approximation.

Table 2. Demographic and Baseline Characteristics of Pediatric Patients with Invasive Group A Streptococcus Infection, by Study Period
p-values were obtained comparing pre- and post-pandemic variables, using Chi-square or Fisher's exact tests for categorical variables and the Mann-Whitney U test for continuous variables. IQR = Interquartile range

Table 3. Clinical Features, Hospital Course, Treatment, and Outcomes of Pediatric Invasive Group A Streptococcus Infections, by Study Period
p-values were obtained comparing pre- and post-pandemic variables, using Chi-square or Fisher's exact tests for categorical variables and the Mann-Whitney U test for continuous variables. PICU, Pediatric Intensive Care Unit; NICU, Neonatal Intensive Care Unit; CICU, Cardiac Intensive Care Unit; PIMCU, Pediatric Intermediate Care Unit; WBC, white blood cell count; ANC, absolute neutrophil count; ALC, absolute lymphocyte count; CRP, C-reactive protein; ECMO, extracorporeal membrane oxygenation; CPAP, continuous positive airway pressure; LFNC, low-flow nasal cannula; HFNC, high-flow nasal cannula; STSS, streptococcal toxic shock syndrome; IVIG, intravenous immunoglobulin; PSI, protein synthesis inhibitor; LOS, length of stay.