Comparison of Clinical Characteristics of Patients with Asymptomatic vs Symptomatic Coronavirus Disease 2019 in Wuhan, China

Abstract

IntroductionCoronavirus disease 2019 (COVID-19) emerged in Wuhan, China, in December 2019 and has spread globally with sustained human-to-human transmission outside China.1,2 To control the spread of COVID-19 and isolate patients as early as possible, the Chinese government requested that close contacts of individuals with COVID-19 must be screened for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.During the screening process, we found some patients whose test results were positive for SARS-CoV-2 but who had no symptoms or signs throughout the course of the disease.Considering that little is known about the differences of clinical features and prognosis between patients who were asymptomatic vs those who were symptomatic, 3,4 this case series aimed to describe the clinical characteristics of patients with SARS-CoV-2 infection confirmed by reverse transcription-polymerase chain reaction (RT-PCR) from 26 transmission cluster series in Wuhan, China, from December 24, 2019, to February 24, 2020. MethodsThis case series was approved by the institutional ethics board of Zhongnan Hospital of Wuhan University.All consecutive patients with COVID-19 confirmed via RT-PCR admitted to Zhongnan Hospital of Wuhan University from December 24, 2019, to February 24, 2020, were enrolled.Oral informed consent was obtained from all patients.Epidemiological, symptoms, signs, laboratory values, chest computed tomography (CT) scans, treatment measures, and outcomes data during the hospital stay were collected.Nasopharyngeal swab samples were collected for extracting SARS-CoV-2 RNA from patients suspected of having SARS-CoV-2 infection.The indicative patients were recruited from 26 cluster cases and had confirmed history of exposure to the Huanan seafood market or had close contact with another patient who had been hospitalized for COVID-19, and they were confirmed to have SARS-CoV-2 infection by RT-PCR from nasopharyngeal swabs.Routine chest CT scans and SARS-CoV-2 testing from nasopharyngeal swab were performed on their close contacts.The close contacts with other exposure histories were excluded.The included patients who were exposed to the same indicative patients with COVID-19 were defined as clustered cases, and the date of initial exposure was identified to determine incubation period.Data were analyzed using SPSS statistical software version 19.0 (IBM).Categorical variables were described as frequency rates and percentages, and continuous variables were described using mean, median, and interquartile range (IQR) values.χ 2 analysis was conducted to compare the distributions of categorical variables (ie, sex, baseline liver injury, fluctuated results of SARS-CoV-2 test, and death) between asymptomatic and symptomatic patients.Continuous variables (ie, age, duration of viral shedding, duration of lung recovery, maximum difference of CD4 lymphocytes during treatment, and CD4 lymphocyte count during recovery) were compared using t tests.All P values were 2-tailed, and P < .05 was considered to be significant.