Incidence of SARS-CoV-2 infection and associated risk factors among staff and residents at homeless shelters in King County, Washington: an active surveillance study (preprint)

Homeless shelter residents and staff may be at higher risk of SARS-CoV-2 infection. However, SARS-CoV-2 infection estimates in this population have been reliant on cross-sectional or outbreak investigation data. We conducted routine surveillance and outbreak testing in 23 homeless shelters in King County, Washington to estimate the occurrence of laboratory-confirmed SARS-CoV-2 infection and risk factors during 1/1/2020-5/31/2021. Symptom surveys and nasal swabs were collected for SARS-CoV-2 testing by RT-PCR for residents aged 3 months and older and staff. We collected 12,915 specimens from 2,930 unique participants. We identified 4.74 (95% CI 4.00-5.58) SARS-CoV-2 infections per 100 individuals (residents: 4.96, 95% CI 4.12-5.91; staff: 3.86, 95% CI 2.43-5.79). Most infections were asymptomatic at time of detection (74%) and detected during routine surveillance (73%). Outbreak testing yielded higher test positivity compared to routine surveillance (2.7% vs. 0.9%). Among those infected, residents were less likely to report symptoms than staff. Participants who were vaccinated against seasonal influenza and were current smokers had lower odds of having an infection detected. Active surveillance that includes SARS-CoV-2 testing of all persons is essential in ascertaining the true burden of SARS-CoV-2 infections among residents and staff of congregate settings.

A qualitative assessment of cleaning and hand hygiene practices at shelters serving people experiencing homelessness during the COVID-19 pandemic, Atlanta, GA – May-June, 2020. (preprint)

Background: Cleaning practices and hand hygiene are important behaviors to prevent and control the spread of infectious disease, especially in congregate settings. This project explored hygiene- and cleaning-related experiences in shelters serving people experiencing homelessness (PEH) during May–June 2020 of the COVID-19 pandemic. Methods: We conducted qualitative, in-depth interviews by phone with 22 staff from six shelters in Atlanta, Georgia. The interview guide included questions about cleaning routines, cleaning barriers and facilitators, cleaning promotion, hand hygiene promotion, and hand hygiene barriers and facilitators. We analyzed interview transcripts using thematic analysis. Results: Multiple individuals, such as shelter individuals (clients), volunteers, and staff, played a role in shelter cleaning. Staff reported engaging in frequent hand hygiene and cleaning practices. Barriers to cleaning included staffing shortages and access to cleaning supplies. Staff reported barriers (e.g., differing perceptions of cleanliness) for clients who were often involved in cleaning activities. Barriers to hand hygiene included limited time to wash hands, forgetting, and inconvenient handwashing facilities. Specific guidance about when and how to clean, and what supplies to use, were requested. Conclusion: During the early months of the COVID-19 pandemic, shelters serving PEH in the Atlanta-metro area needed resources and support to ensure sufficient staffing and supplies for cleaning activities. As part of future pandemic planning and outbreak prevention efforts, shelters serving PEH could benefit from specific guidance and training materials on cleaning and hand hygiene practices.

Outbreak of COVID-19 among vaccinated and unvaccinated homeless shelter residents — Sonoma County, California, July 2021 (preprint)

In July 2021, the Sonoma County Health Department was alerted to three cases of COVID-19 among residents of a homeless shelter in Santa Rosa, California. Among 153 shelter residents, 83 (54%) were fully vaccinated; 71 (86%) vaccinated residents had received the Janssen COVID-19 vaccine and 12 (14%) received an mRNA (Pfizer BioNTech or Moderna) COVID-19 vaccine. Within 1 month, 116 shelter residents (76%) received positive SARS-CoV-2 test results, including 66 fully vaccinated residents and 50 not fully vaccinated. 9 fully vaccinated and 1 unvaccinated were hospitalized for COVID-19. All hospitalized cases had at least one underlying medical condition. Two deaths occurred, one in a vaccinated resident and one in a non-vaccinated resident. Specimens from 52 residents underwent whole genome sequencing; all were identified as SARS-CoV-2, Delta Variant AY.13 lineage. Additional mitigation measures are needed in medically vulnerable congregate setting where limited resources make individual quarantine and isolation not feasible.

Occupational exposures and mitigation strategies among homeless shelter workers at risk of COVID-19 (preprint)

Objective: To describe the work environment and COVID-19 mitigation measures for homeless shelter workers and to assess occupational risk factors for COVID-19 infection Methods: Between June 9 and August 10, 2020, we conducted a self-administered, web-based survey among homeless shelter workers in Washington, Massachusetts, Utah, Maryland, and Georgia, in shelters where at least 1 staff person had tested positive for SARS-CoV-2. We calculated frequencies for demographics, work environment, personal protective equipment use, and SARS-CoV-2 testing history. We used generalized linear models with a binary outcome (COVID-19 positivity) and a log link, clustered by shelter network, to produce unadjusted prevalence ratios (PR) for demographics, work environment, and mitigation measures. Results: Of the 106 respondents, 43.4% reported frequent close contact with clients and 85.8% reported wearing a mask most or all of the time; 75% reported being worried about being infected with SARS-CoV-2 at work; 15% reported testing positive for SARS-CoV-2. Of those who reported testing positive for SARS-CoV-2, 80% (12/15) believed they were infected at work. Frequent close contact with clients was significantly associated with testing positive for SARS-CoV-2 (PR 3.97, 95% CI 1.06, 14.93). Conclusions: Homeless shelter workers may be at higher risk of being infected with SARS-CoV-2 during the course of their work.

Modeling the frequency and number of persons to test to detect and control COVID-19 outbreaks in congregate settings (preprint)

BackgroundCongregate settings are at risk for coronavirus disease 2019 (COVID-19) outbreaks. Diagnostic testing can be used as a tool in these settings to identify outbreaks and to control transmission. MethodsWe used transmission modeling to estimate the minimum number of persons to test and the optimal frequency to detect small outbreaks of COVID-19 in a congregate facility. We also estimated the frequency of testing needed to interrupt transmission within a facility. ResultsThe number of people to test and frequency of testing needed depended on turnaround time, facility size, and test characteristics. Parameters are calculated for a variety of scenarios. In a facility of 100 people, 26 randomly selected individuals would need to be tested at least every 6 days to identify a true underlying prevalence of at least 5%, with test sensitivity of 85%, and greater than 95% outbreak detection sensitivity. Disease transmission could be interrupted with universal, facility-wide testing with rapid turnaround every three days. ConclusionsTesting a subset of individuals in congregate settings can improve early detection of small outbreaks of COVID-19. Frequent universal diagnostic testing can be used to interrupt transmission within a facility, but its efficacy is reliant on rapid turnaround of results for isolation of infected individuals.