Children less than 18 years of age account for an estimated 2%-5% of reported severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases globally. Lower prevalence of coronavirus disease 2019 (COVID-19) among children, in addition to higher numbers of mild and asymptomatic cases, continues to provide challenges in determining appropriate prevention and treatment courses. Here, we summarize the current evidence on the transmission, clinical presentation, complications and risk factors in regard to SARS-CoV-2 in children, and highlight crucial gaps in knowledge going forward. Based on current evidence, children are rarely the primary source of secondary transmission in the household or in child care and school settings and are more likely to contract the virus from an adult household member. Higher transmission rates are observed in older children (10-19 years old) compared with younger children ( <10 years old). While increasing incidence of COVID-19 in neonates raises the suspicion of vertical transmission, it is unlikely that breast milk is a vehicle for transmission from mother to infant. The vast majority of clinical cases of COVID-19 in children are mild, but there are rare cases that have developed complications such as multisystem inflammatory syndrome in children, which often presents with severe cardiac symptoms requiring intensive care. Childhood obesity is associated with a higher risk of infection and a more severe clinical presentation. Although immediate mortality rates among children are low, long-term respiratory, and developmental implications of the disease remain unknown in this young and vulnerable population.epidemiology, pulmonology (general), social dimensions of pulmonary medicine | INTRODUCTIONChildren less than 18 years of age account for an estimated 1.7% of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clinical infections in the United States, 1 with global estimates ranging from 2.0 2 to 4.8%. 3 The low prevalence of pediatric cases has made it difficult to draw conclusive statements about many aspects of the virus in this population, but the reported case numbers are likely an underestimation of the true pediatric case load, as many cases in children are mild or asymptomatic. 4 Initial observations report that

Children less than 18 years of age account for an estimated 500,000 to 1.5 million global SARS-CoV-2 cases. Lower prevalence of COVID-19 among children, in addition to higher numbers of mild and asymptomatic cases, continues to provide challenges in determining appropriate prevention and treatment courses. Here, we summarize the current evidence on the transmission, clinical presentation, complications and risk factors in regards to SARS-CoV-2 in children and highlight crucial gaps in knowledge going forward. Based on current evidence, children are rarely the primary source of secondary transmission in the household or in child care and school settings and are more likely to contract the virus from an adult household member. Higher transmission rates are observed in older children (10-19 years old) compared to younger children (<10 years old). While increasing incidence of COVID-19 in neonates raises the suspicion of vertical transmission, it is unlikely that breast milk is a vehicle for transmission from mother to infant. The vast majority of clinical cases of COVID-19 in children are mild, but there are rare cases that have developed complications such as multisystem inflammatory syndrome in children (MIS-C), which often presents with severe cardiac symptoms requiring intensive care. Childhood obesity is associated with a higher risk of infection and a more severe clinical presentation. Although immediate mortality rates among children are low, long-term respiratory and developmental implications of the disease remain unknown in this young and vulnerable population.