Epidemiological and clinical differences of coronavirus disease 2019 patients with distinct viral exposure history

Since severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread from the early epicenter, Wuhan, to the rest of China, the virulence of SARS-CoV-2 might have evolved at different phases of the pandemic. We therefore compared the unique features among 62 coronavirus disease 2019 (COVID-19) inpatients who contracted SARS-CoV-2 in Wuhan (15 cases), exposed to the patients from Wuhan (26 cases), or acquired the disease without exposure to Wuhan patients (21 cases). Median incubation periods are 4.5 days (3–5) for Wuhan patients, 8 days (3–11) for those infected by Wuhan patients, and 12 days (7–13) for those without aforementioned experience. The disease onset dates are earliest for Wuhan patients and latest for those without exposure to Wuhan patients. Blood lymphocytes were lowest in Wuhan patients, lower in those affected by Wuhan patients, and modest reduced in remaining ones. Disease severity is worst for Wuhan patients, and modest for those without contact with Wuhan patients. Wuhan patients had longest (27 days, 18–28), those transmitted by Wuhan patients had intermediate (16 days, 8–23), and the rest of the patients had shortest (13 days, 8.5–22.5) hospital stay. Early viral exposure, older age, lymphocytopenia, and underlying conditions are risk factors which warrant aggressive intervention. Even though the virulence of SARS-CoV-2 appears decline over the course of serial transmissions, viral testing, contact tracing, social distancing, and face masking should be imposed on general public to contain viral dissemination from both symptomatic and asymptomatic patients with this highly contagious disease.