Contributor: Jared Scott MD Educational Pearls A recently published study assessed the burden of respiratory viruses in a longitudinal cohort of children from 0 to 2 years of age The children in the study received nasal swab PCR testing weekly to determine infectivity They were also monitored for symptoms via weekly text surveys The study differentiated between infection and illness by defining an acute respiratory illness (ARI) as fever ≥38°C or cough.  The median infectivity rate was 9.4 viral infections per child per year The median illness rate was 3.3 ARIs per child per year The most common etiological viruses isolated from the nasal samples were rhinovirus and enterovirus Most infections were asymptomatic or mild References Teoh, Z., Conrey, S., McNeal, M., Burrell, A., Burke, R. M., Mattison, C., McMorrow, M., Payne, D. C., Morrow, A. L., & Staat, M. A. (2023). Burden of Respiratory Viruses in Children Less Than 2 Years Old in a Community-based Longitudinal US Birth Cohort. Clinical infectious diseases: an official publication of the Infectious Diseases Society of America, 77(6), 901–909. https://doi.org/10.1093/cid/ciad289 Summarized by Jorge Chalit, OMSII | Edited by Meg Joyce & Jorge Chalit, OMSII