Differences of clinical and imaging findings in multiple generations of secondary COVID-19 infection in Xi'an, China

PURPOSE: In the global presence of secondary infections with the coronavirus disease 2019 (COVID-19), little is known about the transmission characteristics of COVID-19 outside Wuhan, China. We evaluated differences in clinic and radiologic findings of multiple generations of COVID-19 infection in Xi9an (Shaanxi, China) to provide more clues for the correct estimate of the disease. METHODS: All COVID-19 infected patients reported in Xi9an up to 10 February 2020 were included for this analysis. Among these cases, clinical and chest CT data of 62 cases were obtained from three hospital in Xi9an. With this information, patients were grouped on basis of exposure history and transmission chains as first-generation, second-generation and third-generation patients. We described clinical characteristics and evaluated CT score/patterns in these COVID-19 cases. RESULTS: There was a clear age differences in multiple generations with COVID-19 infection. Above two thirds of the second-generation (75.0%) and third-generation patients (77.8%) were aged ≥45 years while 40.0% of first-generation cases at this age (p=0.001). More than half of second-generation patients (52.8%) and third-generation patients (55.6%) have comorbidities and is predominantly hypertensive (22.8% of second-generation vs. 27.8% of third-generation infections). The main exposure of second- and third-generation patients in Xi9an is family exposure (35.2%). For evaluation of CT findings of pulmonary involvement, the total CT score were 4.22±3.00 in first-generation group, 4.35±3.03 in second-generation group and 7.62±3.56 in third-generation group (p<0.001). In all of three generations, the predominant pattern of abnormality observed was organizing pneumonia (65.5% in first-generation group, 61.5% in second-generation group and 71.4% in third-generation group). The average courses of the disease in third-generation infections has obviously extension (22.93±7.22 days of first-generation, 21.53±8.31 days of second-generation vs. 31.00±8.12 days of third-generation group, p=0.004). There were no significant differences of the pulmonary sequelae among three generation patients. CONCLUSION: There is more serious pulmonary infection of COVID-19 pneumonia in second- and third-generation patients, which might be attribute to the elder age and comorbidity of these patients.