Children may carry much coronavirus in their system than previously thought, a new study suggests. Infected children were shown to have a significantly higher level of virus in their airways than hospitalised adults in ICUs for Covid-19 treatment, researchers say. As schools plan to reopen, understanding the potential role children play in the spread of the disease and the factors that drive severe illness in children is critical, experts say.Researchers from Massachusetts General Hospital (MGH) and Mass General Hospital for Children (MGHfC) in the US, suggest their findings indicate may children play a larger role in the community spread of the virus than previously thought. In a study of 192 children aged 0-22, 49 children tested positive for coronavirus, and an additional 18 had late-onset, Covid-19-related illness. Lael Yonker, director of the MGH Cystic Fibrosis Centre, and lead author of the study, said: “I was surprised by the high levels of virus we found in children of all ages, especially in the first two days of infection.“I was not expecting the viral load to be so high. “You think of a hospital, and of all of the precautions taken to treat severely ill adults, but the viral loads of these hospitalised patients are significantly lower than a ‘healthy child’ who is walking around with a high Sars-CoV-2 viral load.” Viral load refers to the amount of virus in a person’s blood. Even when children exhibit Covid-19 symptoms like fever and cough, they often overlap with common childhood illnesses, including flu and the common cold. Dr Yonker says this confounds an accurate diagnosis of Covid-19.As well as viral load, researchers examined expression of the viral receptor and antibody response in healthy children, children with acute Sars-CoV-2 infection and a smaller number of children with Multisystem Inflammatory Syndrome in Children (MIS-C). Alessio Fasano, director of the mucosal immunology and biology research centre at MGH and senior author of the study, said: “Kids are not immune from this infection, and their symptoms don’t correlate with exposure and infection.