Risk of Airborne Transmission During Home Isolation : A Modeling Study

Objective: The worldwide pandemic of SARS-CoV-2 and its B.1.1.529 variant, Omicron, remain a threat to health. In Japan, self-isolation in a room at home has been recommended in some prefectures to reduce the burden on hospitals. With the aim of preventing the infection of family members in other rooms, this study quantified the risk of infection by airborne transmission to mask-wearing, non-infected members of the household. Methods: A mathematical modeling approach was used to estimate the risk of airborne infection. Results: For pre-SARS-CoV-2 variants of concern (VOC), the risk of infection of non-mask-wearing family members had an LN distribution with GM of 0.11, GD of 5.38, and median of 0.11; whereas that of mask-wearing members had an LN distribution with GM of 0.05, GD of 5.46, and median of 0.05. For Delta variant, the risk of infection of non-mask-wearing family members had an LN distribution with GM of 0.39, GD of 76.30, and median of 0.40, and that of mask-wearing members had an LN distribution with GM of 0.18, GD of 76.30, and median of 0.18. The difference of these medians was 0.22, which suggests that family members wearing masks is effective for preventing infection, even for highly infectious variants.