PT - JOURNAL ARTICLE AU - McKaylee M Robertson AU - Sarah Gorrell Kulkarni AU - Madhura Rane AU - Shivani Kochhar AU - Amanda Berry AU - Mindy Chang AU - Chloe Mirzayi AU - William You AU - Andrew Maroko AU - Rebecca Zimba AU - Drew Westmoreland AU - Christian Grov AU - Angela Marie Parcesepe AU - Levi Waldron AU - Denis Nash ED - , TI - Cohort profile: a national, community-based prospective cohort study of SARS-CoV-2 pandemic outcomes in the USA—the CHASING COVID Cohort study AID - 10.1136/bmjopen-2021-048778 DP - 2021 Sep 01 TA - BMJ Open PG - e048778 VI - 11 IP - 9 4099 - http://bmjopen.bmj.com/content/11/9/e048778.short 4100 - http://bmjopen.bmj.com/content/11/9/e048778.full SO - BMJ Open2021 Sep 01; 11 AB - Purpose The Communities, Households and SARS-CoV-2 Epidemiology (CHASING) COVID Cohort Study is a community-based prospective cohort study launched during the upswing of the USA COVID-19 epidemic. The objectives of the cohort study are to: (1) estimate and evaluate determinants of the incidence of SARS-CoV-2 infection, disease and deaths; (2) assess the impact of the pandemic on psychosocial and economic outcomes and (3) assess the uptake of pandemic mitigation strategies.Participants We began enrolling participants from 28 March 2020 using internet-based strategies. Adults≥18 years residing anywhere in the USA or US territories were eligible. 6740 people are enrolled in the cohort, including participants from all 50 US states, the District of Columbia, Puerto Rico and Guam. Participants are contacted regularly to complete study assessments, including interviews and dried blood spot specimen collection for serologic testing.Findings to date Participants are geographically and sociodemographically diverse and include essential workers (19%). 84.2% remain engaged in cohort follow-up activities after enrolment. Data have been used to assess SARS-CoV-2 cumulative incidence, seroincidence and related risk factors at different phases of the US pandemic; the role of household crowding and the presence of children in the household as potential risk factors for severe COVID-19 early in the US pandemic; to describe the prevalence of anxiety symptoms and its relationship to COVID-19 outcomes and other potential stressors; to identify preferences for SARS-CoV-2 diagnostic testing when community transmission is on the rise via a discrete choice experiment and to assess vaccine hesitancy over time and its relationship to vaccine uptake.Future plans The CHASING COVID Cohort Study has outlined a research agenda that involves ongoing monitoring of the incidence and determinants of SARS-CoV-2 outcomes, mental health outcomes and economic outcomes. Additional priorities include assessing the incidence, prevalence and correlates of long-haul COVID-19.Data are available upon reasonable request. The authors will post a deidentified, HIPAA compliant, public use version of visit 1 and follow-up data on Backblaze, a secure cloud storage provider. Data will be presented as flat text files (CSV) formatted for compatibility with county-level longitudinal case load datasets, including date, county, state and FIPS code. The authors will exclude counties with <20 000 residents to protect participant privacy. The authors will continue to provide direct feedback to their cohort and other stakeholders who have signed up for updates via follow-up emails to participants and the City University of New York Institute for Implementation Science in Population Health Study website.