Health and economic impact of COVID-19, surveillance, and vaccination among people experiencing homelessness in Seattle-King County, Washington

The COVID-19 pandemic has disproportionately affected people experiencing homelessness, with shelters often representing a hotspot for outbreaks due to the elevated risk of viral transmission. COVID-19 surveillance in congregate living settings is vital for mitigating pandemic-related harms, especially among high-risk populations. Additionally, ensuring high COVID-19 vaccination coverage is crucial to prevent morbidity and mortality. However, the impact of COVID-19 and mitigation measures among homeless shelter populations remains uncertain. In the following dissertation, we address these gaps utilizing both longitudinal and cross-sectional data from the Seattle Flu Study among adults in 23 congregate shelters in the Seattle-King County area from January 2020 through April 2022. In Chapter 1 we evaluate the prevalence, characteristics, and impact of long COVID among sheltered people experiencing homelessness and assess the risk of symptom presence at follow-up among those who tested positive versus negative for SARS-CoV-2. In Chapter 2 we describe shelter staff and residents’ experiences and perceptions of COVID-19 vaccination over time, as well as provide recommendations to improve vaccine acceptability among people experiencing homelessness. This utilized a mixed-methods approach with both quantitative surveys (Chapter 2a) and qualitative semi-structured interviews and focus groups (Chapter 2b) to explore characteristics and reasons associated with changes in vaccine attitudes. In Chapter 3 we develop a Markov model to estimate health outcomes and costs to determine the cost-utility of pandemic COVID-19 surveillance testing in homeless shelters by vaccination coverage. We found that shelter residents reported a high prevalence of symptoms 30+ days after their SARS-CoV-2 detection, though few accessed medical care for persistent illness. Intent to be vaccinated against COVID-19 increased from 45% when recalling attitudes in March 2020 to 74% as of August 2021, and was similar among residents and staff. Participants presented recommendations to improve COVID-19 vaccination information content and dissemination, vaccine access, and use of incentives to improve coverage in shelter settings. Modeled findings emphasized that implementation of COVID-19 testing at shelters can be a cost-effective pandemic response. Altogether, these results highlight the burden of long COVID, the cost-effectiveness of surveillance, and opportunities to improve vaccination coverage with shelter residents and staff. Findings support recommendations for COVID-19 and future outbreak mitigation for key stakeholders, including shelters, public health, and policymakers.