427. Underlying Medical Conditions and Vaccination Status among U.S. Children Aged ≤17 Years Hospitalized for COVID-19 in COVID-19-Associated Hospitalization Surveillance Network (COVID-NET), January–December 2023

Abstract Background SARS-CoV-2 infection can result in serious illness in children. We used COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) data to assess characteristics associated with pediatric COVID-19 hospitalizations, including underlying medical conditions and vaccination status. Percent of COVID-19-Associated Hospitalizations† with Specific Underlying Medical Conditions among U.S. Children Aged ≤17 Years by Age Group — COVID-NET, January–December 2023 Methods U.S. children aged ≤ 17 years with COVID-19 as the likely primary reason for hospitalization during January–December 2023 were identified in the population-based COVID-NET active surveillance system, which includes patients residing in a catchment area of > 300 acute care hospitals in 13 states with a positive SARS-CoV-2 test result during or ≤ 14 days before admission. Medical records of a random sample of children stratified by age-group and site were abstracted; reported percentages were weighted to account for probability of selection. We assessed patient age, underlying medical conditions, and receipt of vaccine dose within 12 months before illness. Results Of 2016 children hospitalized for COVID-19, 1232 (61%) were aged < 2 years (611 aged < 6 months; 621 aged 6–23 months). Overall, 51% had no underlying condition, including 73% of infants aged < 6 months, 58% of children aged 6–23 months, and 24% of children aged 12–17 years (Figure). Among children aged < 2 years, prematurity was the most common underlying condition (17–20%). Neurologic disorders (27–31%) and asthma (21–33%) were most prevalent among children aged ≥ 2 years. Among 1379 children aged ≥ 6 months eligible for vaccination with vaccine data available, only 14% had received ≥ 1 vaccine dose within 12 months before illness, with the lowest frequency (9%) among children aged 6–23 months (Table). Among age-eligible children with neurologic disorders and asthma, only 18% and 16% were vaccinated, respectively. Conclusion Most children aged < 2 years hospitalized for COVID-19 during 2023 had no underlying conditions; underlying conditions were more prevalent among older children. More than 85% of age-eligible children had not received a vaccine dose within 12 months, including among children with underlying conditions. Increasing pediatric COVID-19 vaccination, especially among children with underlying medical conditions, could help reduce COVID-19 hospitalizations. Disclosures Anna Falkowski, Master of Science, Council of State and Territorial Epidemiologists (CSTE): Grant/Research Support