Difference in SARS-CoV-2 attack rate between children and adults may reflect bias

The epidemiology of coronavirus disease 2019 (COVID-19) in children has been challenging to establish, owing to the high prevalence of asymptomatic infection in this population. Lower secondary attack rates in children compared to adults have been observed in household contact studies, but there is evidence this may reflect lower testing in children and reduced exposure, rather than a genuine difference in biological susceptibility. Additionally, children may shed infectious virus for a shorter period than adults and their antibody response may be less broad, with implications for both polymerase chain reaction and serological testing. Improvements in study design, data collection, and data interpretation are required to better understand the epidemiology of COVID-19 in children.