SARS-CoV-2 and Respiratory Virus Co-Infections Among Young Children - PROJECT SUMMARY In the US alone, SARS-CoV-2 (the virus causing COVID-19) has resulted in more than 25.8 million infections, 266,000 hospitalizations, and nearly 1,000 deaths among children. Although COVID-19 is typically more mild in children compared to adults, it remains in the top ten causes of pediatric death and is the leading infectious cause of death for children. Children also experience complications associated with COVID-19, including respiratory failure, acute cardiac, kidney and liver injury, and multisystem inflammatory syndrome in children (MIS-C). The risk of COVID-19 is two-fold higher among children 0-2 years old and children with chronic lung disease, neurologic disorders, cardiovascular disease, prematurity, and airway abnormalities. Following the emergence of the Omicron SARS-CoV-2 variant, the incidence of SARS-CoV-2 infection has increased by 6-8 fold among young children, and an unanticipated increase in the incidence and morbidity attributed to other circulating respiratory virus infections, including respiratory syncytial virus (RSV), have been observed in young children. Other respiratory viruses co-circulating with SARS-CoV-2 may exacerbate the morbidity and mortality attributed to pediatric respiratory infections. Co-infections between SARS-CoV-2 and influenza, RSV, and rhinoviruses are more common among young children 0-2 years of age compared to adults and are associated with more severe illness and frequent complications. Despite this, existing data on SARS-CoV-2 co-infections have predominantly come from small, regionally-specific samples of children 0-18 years old, and the ill-health effects associated with SARS-CoV-2 co-infections in young children and children with underlying health conditions (i.e., those most vulnerable to severe illness) are not well understood. Although COVID-19 vaccines have been available to children since June 2022, the effects of vaccination on the severity of SARS-CoV-2 co- infections are unknown. Using national commercial insurance and multi-state Medicaid claims data from a cohort of >100,965 SARS- CoV-2-infected U.S. children, our overall goal is to characterize the severity of SARS-CoV-2 co-infections and the effects of COVID-19 vaccination on disease severity. As of May 2023, just 13% of children 6 months to 4 years old have received at least one dose of COVID-19 vaccine – rates lower than any other age group in the U.S. Completion of this proposed research will provide more comprehensive evidence on the burden of COVID-19 in young children and potential benefits associated with pediatric COVID-19 vaccination. Such evidence is useful for understanding the risks and benefits of COVID-19 vaccination in healthy and high-risk children and will aid evidence-based pediatric immunization policy and informed decision-making among parents/caregivers of young children and their healthcare provider(s) .
