Background: Homeless shelters are a high-risk setting for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission because of crowding and shared hygiene facilities.
Objective: To investigate SARS-CoV-2 case counts across several adult and family homeless shelters in a major metropolitan area.
Design: Cross-sectional, community-based surveillance study. (ClinicalTrials.gov: NCT04141917).
Setting: 14 homeless shelters in King County, Washington.
Participants: A total of 1434 study encounters were done in shelter residents and staff, regardless of symptoms.
Intervention: 2 strategies were used for SARS-CoV-2 testing: routine surveillance and contact tracing ("surge testing") events.
Measurements: The primary outcome measure was test positivity rate of SARS-CoV-2 infection at shelters, determined by dividing the number of positive cases by the total number of participant encounters, regardless of symptoms. Sociodemographic, clinical, and virologic variables were assessed as correlates of viral positivity.
Results: Among 1434 encounters, 29 (2% [95% CI, 1.4% to 2.9%]) cases of SARS-CoV-2 infection were detected across 5 shelters. Most (n = 21 [72.4%]) were detected during surge testing events rather than routine surveillance, and most (n = 21 [72.4% {CI, 52.8% to 87.3%}]) were asymptomatic at the time of sample collection. Persons who were positive for SARS-CoV-2 were more frequently aged 60 years or older than those without SARS-CoV-2 (44.8% vs. 15.9%). Eighty-six percent of persons with positive test results slept in a communal space rather than in a private or shared room.
Limitation: Selection bias due to voluntary participation and a relatively small case count.
Conclusion: Active surveillance and surge testing were used to detect multiple cases of asymptomatic and symptomatic SARS-CoV-2 infection in homeless shelters. The findings suggest an unmet need for routine viral testing outside of clinical settings for homeless populations.
Primary funding source: Gates Ventures.