As the global and pandemic spread of the novel coronavirus (SARS-CoV-2, COVID-19) continues, many knowledge gaps remain with regard to the epidemiology and transmission of infection, as well as the normal immunological responses after viral exposure. Cincinnati only recently (March 14, 2020) had its first confirmed case of COVID-19, and through shelter-in-place and social distancing efforts, has avoided the community spread experienced by some other large metropolitan areas. As investigators contemplate the gradual reintroduction of the Cincinnati Children's Hospital Medical Center (CCHMC) workforce back into the hospital, it is imperative that investigators determine the current prevalence of infection among CCHMC employees, measure the cumulative incidence of infection over the next 12 months, investigate the normal antibody patterns after infection, and help elucidate what constitutes a protective immunological response. Investigators have a unique but time-limited opportunity to optimally track the epidemiology and natural history of SARS-CoV-2 infection at CCHMC, including risk factors for transmission and immunological recovery. RETURN will investigate epidemiological and immunological features of SARS-CoV-2 virus infection in a limited cohort of CCHMC employees, as they return from the current shelter-at-home directive toward a normal work environment. By collecting and analyzing weekly serial samples for SARS-CoV-2 (nasal swab for virus by PCR) and monthly serological exposure (serum antibodies by ELISA), investigators will determine the prevalence and cumulative incidence of exposure to SARS-CoV-2; document the antibody responses over time; identify cases of apparent viral recrudescence or re-infection; and create models of transmission risk among CCHMC employees.