Clinical Features and Follow-Up of SARS-Cov-2 Asymptomatic Carriers

In the current global coronavirus disease (COVID-19) pandemic, asymptomatic transmission of the causative agent, severe acute respiratory coronavirus-2 (SARS-CoV-2), poses a considerable challenge for disease control. Furthermore, information on the clinical characteristics of asymptomatic carriers is limited. Here, we aimed to clarify the clinical features and obtain follow-up data of asymptomatic carriers to assist in the clinical management of carriers. This retrospective study included all asymptomatic SARS-CoV-2 carriers diagnosed at the First People’s Hospital of Yueyang (Hunan, China) and Hunan Provincial People’s Hospital (Changsha, China) between January 22 and March 26, 2020. Data including the epidemiology, clinical characteristics, laboratory test results, and chest computed tomography status were collected, with a follow-up of these cases. A total of 24 asymptomatic carriers were enrolled at the First People’s Hospital of Yueyang and Hunan Provincial People’s Hospital between 22 January 2020 and 26 March 2020. All patients had previously been exposed to SARS-CoV-2. Over the monitored time, patients experienced no symptoms and most laboratory findings were normal. The median time from contact to diagnosis was 9.6 days (range: 1-38 days), while that from diagnosis to discharge was 14.4 days (range: 6-24 days). Following discharge, all patients remained asymptomatic. However, five patients (20.83%) were re-admitted because a polymerase chain reaction (PCR)-based re-test of their specimens (4 throat swabs and 1 feces) showed that they were positive for SARS-CoV-2. The time to re-testing positively varied from 23 to 53 days post-diagnosis. The time to re-testing negative for SARS-CoV-2 by real-time reverse transcription PCR after re-testing positive was 3 to 11 days. In conclusion, although asymptomatic carriers have favorable outcomes, they should be closely monitored. Also, clear guidelines need to be formulated and close surveillance is required for the management of asymptomatic carriers.