A retrospective analysis of the epidemiology, clinical manifestations, and imaging characteristics of familial cluster-onset COVID-19

BACKGROUND: The coronavirus disease 2019 (COVID-19) virus has a high incidence rate and strong infectivity. The diagnosis and evaluation of familial outbreaks requires a collective consideration of epidemiological history, molecular detection methods, chest computed tomography (CT), and clinical symptoms. METHODS: A group of family patients with COVID-19 diagnosed in Guizhou, China, in February 2020, was retrospectively analyzed. As of March 1, all patients in the group have been discharged from hospital. This study tracked all patients in the group. We report the epidemiology, radiological characteristics, treatment, and clinical outcomes of these patients. RESULTS: We collected a group of 8 clustered cases (3 men and 5 women) from a family with confirmed COVID-19 infection. In the first admission diagnosis, according to the degree of clinical symptoms, the 8 patients were defined as mild type (4/8) or moderate type (4/8). They were also divided according to the CT findings into early period (1/8), progressive period (3/8), and negative on CT scan (4/8); for the first 4 patients, the corresponding CT image scores were 1, 4, 5, and 5 respectively. In this group of COVID-19 patients, half of the patients showed occult clinical manifestations and negative CT performance. We defined these patients as COVID-19-infected patients, or asymptomatic carriers. CONCLUSIONS: The family cluster analysis indicated that COVID-19-infected patients (asymptomatic carriers) and symptomatic COVID-19 patients are distinct but coexistent. This may indicate that the infectivity and virulence of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has decreased. In order to block the transmission pathway of this virus before it spreads, we need to identify the presence of asymptomatic carriers as early as possible.