LAUSR

We primarily quantified exposure patterns, transmission characteristics, and the clinical spectrum of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection among household contacts of individuals with severe coronavirus disease‐2019 (COVID‐19). We conducted a retrospective cohort study of 20 index patients hospitalized with severe COVID‐19 and 79 of their household contacts. We determined the transmission frequency, range of manifestations of SARS‐CoV‐2 infection, and factors associated with infection in household settings. Of the 79 household contacts, 53 (67%) developed SARS‐CoV‐2 infection (49 [62%] symptomatic, 4 [5%] asymptomatic). Eight patients (10%) developed severe COVID‐19, and one died of COVID‐19 pneumonia (case‐fatality rate: 1.9%). The probability of SARS‐CoV‐2 infection was similar in children and adults (55% vs. 72%, p = .14), with children being less likely to develop the symptomatic disease (46% vs. 68%, p = .06). Handwashing ≥ 5 times/day was associated with reduced infection risk (52.8% vs. 76.9%, p = .04). SARS‐CoV‐2 has a high frequency of transmission among household contacts. Nonhospitalized individuals with SARS‐CoV‐2 infection should be quarantined in patient care facilities rather than at home to minimize spread, if possible, and frequent handwashing should be practiced to prevent transmission.