Risk factors for SARS-CoV-2 infection in homeless shelters in Chicago, Illinois – March-May, 2020

Ghinai, Isaac; Davis, Elizabeth S; Mayer, Stockton; Toews, Karrie-Ann; Huggett, Thomas D; Snow-Hill, Nyssa; Perez, Omar; Hayden, Mary K; Tehrani, Seena; Landi, A Justine; Crane, Stephanie; Bell, Elizabeth; Hermes, Joy-Marie; Desai, Kush; Godbee, Michelle; Jhaveri, Naman; Borah, Brian; Cable, Tracy; Sami, Sofia; Nozicka, Laura; Chang, Yi-Shin; Jagadish, Aditi; Chee, Mark; Thigpen, Brynna; Llerena, Christopher; Tran, Minh; Surabhi, Divya Meher; Smith, Emilia D; Remus, Rosemary G; Staszcuk, Roweine; Figueroa, Evelyn; Leo, Paul; Detmer, Wayne M; Lyon, Evan; Carreon, Sarah; Hoferka, Stacey; Ritger, Kathleen A; Jasmin, Wilnise; Nagireddy, Prathima; Seo, Jennifer Y; Fricchione, Marielle J; Kerins, Janna L; Black, Stephanie R; Butler, Lisa Morrison; Howard, Kimberly; McCauley, Maura; Fraley, Todd; Arwady, M Allison; Gretsch, Stephanie; Cunningham, Megan; Pacilli, Massimo; Ruestow, Peter S; Mosites, Emily; Avery, Elizabeth; Longcoy, Joshua; Lynch, Elizabeth B; Layden, Jennifer E

BACKGROUND: People experiencing homelessness are at increased risk of COVID-19, but little is known about specific risk factors for infection within homeless shelters. METHODS: We performed widespread SARS-CoV-2 PCR testing and collected risk factor information at all homeless shelters in Chicago with at least one reported case of COVID-19 (n=21). Multivariable, mixed-effects log-binomial models were built to estimate adjusted prevalence ratios (aPRs) for SARS-CoV-2 infection for both individual and facility-level risk factors. RESULTS: During March 1 to May 1, 2020, 1717 shelter residents and staff were tested for SARS-CoV-2; 472 (27%) persons tested positive. Prevalence of infection was higher for residents (431/1435, 30%) than for staff (41/282, 15%) (prevalence ratio [PR] =2.52, 95% CI 1.78–3.58). The majority of residents with SARS-CoV-2 infection (293/406 with available information about symptoms, 72%) reported no symptoms at the time of specimen collection or within the following two weeks.Among residents, sharing a room with a large number of people was associated with increased likelihood of infection (aPR for sharing with >20 people compared to single rooms = 1.76, 95% CI 1.11–2.80), and current smoking was associated with reduced likelihood of infection (aPR=0.71, 95% CI 0.60–0.85). At the facility-level, a higher proportion of residents leaving and returning each day was associated with increased prevalence (aPR=1.08, 95% CI 1.01–1.16), while an increase in the number of private bathrooms was associated with reduced prevalence (aPR for one additional private bathroom per 100 people = 0.92, 95% CI 0.87–0.98). CONCLUSIONS: We identified a high prevalence of SARS-CoV-2 infections in homeless shelters. Reducing the number of residents sharing dormitories might reduce the likelihood of SARS-CoV-2 infection. When community transmission is high, limiting movement of persons experiencing homelessness into and out of shelters might also be beneficial.