Homeless shelters are a high-risk setting for SARS-CoV-2 transmission because of crowding and shared hygiene facilities. The following study is a cross-sectional, community-based surveillance study investigating the SARS-CoV-2 case counts across several adult and family homeless shelters in a central metropolitan area. A total of 1434 study encounters were done in 14 homeless shelters in King County, Washington, regardless of symptoms. Intervention strategies used were routine surveillance and contact tracing events.
Among 1434 encounters, 29 cases of SARS-CoV-2 infection were detected across 5 shelters. Of these encounters, 601 (41.9%) involved asymptomatic persons, and 833 (58.1%) involved symptomatic persons. Most cases were detected during surge testing events rather than routine surveillance, and participants were asymptomatic at the time of sample collection. Positives for SARS-CoV-2 were more commonly aged 60 years or higher than those without SARS-CoV-2. 86% participants with positive test results slept in a communal space.
In conclusion, this study provides critical insights into detection strategies for SARS-CoV-2 in a vulnerable, hard-to-reach population. The passive sentinel surveillance for respiratory viruses may detect symptomatic cases only, that are severe enough to prompt health-seeking behavior and may miss milder ones, delaying the recognition of outbreaks and further viral spread.