Disease severity among hospitalized children during the COVID-19 pandemic in Israel

COVID-19 typically results in mild illness among children, but severe cases do occur, leading to hospitalizations and critical outcomes such as respiratory failure. High-quality surveillance of COVID-19 presents a unique opportunity to understand risk factors and changing patterns of severity across different pandemic waves. We aimed to assess the burden of COVID-19-related hospitalizations among children in Israel, identify key risk factors for moderate-to-severe disease among hospitalized children, and examine trends in disease severity across different phases of the pandemic. We conducted a retrospective cohort study of all children aged 0–18 years hospitalized with COVID-19 within Maccabi Healthcare Services from March 2020 to November 2023. Data on comorbidities, age, vaccination status, and other covariates were extracted from electronic health records. Disease severity was classified as mild or moderate-to-severe. Logistic regression was used to estimate adjusted odds ratios for moderate-to-severe illness. In a pediatric population of approximately 770,000 children during a 3.5-year study period, 935 COVID-19–related hospitalizations were identified (approximately 35 hospitalizations per 100,000 children per year), and severe outcomes were uncommon. Among hospitalized children, most experienced mild disease (822/935), with 57 moderate cases and 56 severe or critical cases or deaths. Overall, 12.1% of hospitalizations progressed to moderate-to-severe illness. Disease severity was strongly associated with comorbidity burden (OR = 1.98 for one condition; OR = 5.88 for two or more conditions). Lack of vaccination was also associated with higher odds of severe outcomes (OR = 5.94), although estimates were imprecise due to sparse events. Over more than three and a half years of follow-up, COVID-19 was characterized by a minimal burden of severe disease in the pediatric population. Even among hospitalized children, clinically meaningful risk was observed in only a small subset, emphasizing the importance of focused risk stratification rather than broad generalized concern. Overall, these findings highlight the predominantly mild course of COVID-19 in children across successive pandemic periods.