Differential Impact of Nonpharmaceutical Interventions on the Epidemiology of Invasive Bacterial Infections in Children During the Coronavirus Disease 2019 Pandemic

Background: Invasive bacterial infection (IBI) remains a major burden of mortality and morbidity in children. As coronavirus disease 2019 (COVID-19) emerged, stringent nonpharmaceutical interventions (NPIs) were applied worldwide. This study aimed to evaluate the impact of NPIs on pediatric IBI in Korea. Methods: From January 2018 to December 2020, surveillance for pediatric IBIs caused by 9 pathogens (S. pneumoniae, H. influenzae, N. meningitidis, S. agalactiae, S. pyogenes, S. aureus, Salmonella species, L. monocytogenes and E. coli) was performed at 22 hospitals throughout Korea. Annual incidence rates were compared before and after the COVID-19 pandemic. Results: A total of 651 cases were identified and the annual incidence was 194.0 cases per 100,000 in-patients in 2018, 170.0 in 2019 and 172.4 in 2020. Most common pathogen by age group was S. agalactiae in infants < 3 months (n = 129, 46.7%), S. aureus in 3 to < 24 months (n = 35, 37.2%), Salmonella spp. in 24 to < 60 months (n = 24, 34.8%) and S. aureus in children >= 5 years (n = 128, 60.7%). Compared with 2018 to 2019, the incidence rate in 2020 decreased by 57% for invasive pneumococcal disease (26.6 vs. 11.5 per 100,000 in-patients, P = 0.014) and 59% for Salmonella spp. infection (22.8 vs. 9.4 per 100,000 in-patients, P = 0.018). In contrast, no significant changes were observed in invasive infections due to S. aureus, S. agalactiae and E. coli. Conclusions: The NPIs implemented during the COVID-19 pandemic reduced invasive diseases caused by S. pneumoniae and Salmonella spp. but not S. aureus, S. agalactiae and E. coli in children.