The course of mild and moderate Covid-19 infections – the unexpected long-lasting challenge

Xia, Lu; Chen, Jun; Friedemann, Thomas; Yang, Zongguo; Ling, Yun; Liu, Xuhui; Lu, Shuihua; Li, Tao; Song, Zhigang; Huang, Wei; Lu, Yunfei; Schröder, Sven; Lu, Hongzhou

BACKGROUND: The course of disease in mild and moderate COVID-19 has many implications for mobile patients, such as the risk of spread of the infection, the precautions taken and the investigations targeted at preventing transmission. METHODS: 331 adults were hospitalized from 21 January to 22 February 2020 and classified as severe (10%) and critical (4.8%) cases; 1.5% died. 282 (85.2%) mild or moderate cases were admitted to regular wards. Epidemiological, demographic, clinical, chest CT scan, laboratory, treatment and outcome data from patient records were analyzed retrospectively. RESULTS: Patients were symptomatic for 9.82±5.75 (1–37) days. Pulmonary involvement was demonstrated on a chest CT scan in 97.9% of cases. It took 16.81±8.54 (3–49) days from the appearance of the first symptom until 274 patients tested virus-negative in NP swabs, blood, urine, and stool. And, 234 (83%) patients were already asymptomatic for 9.09±7.82 (1–44) days. Subsequently, 131 patients were discharged. 169 remained in hospital, these patients tested virus-free and were clinically asymptomatic, because of widespread persisting or increasing pulmonary infiltrates. Hospitalization took 16.24±7.57 (2–47) days – from the first symptom to discharge the time interval was 21.37±7.85 (3–52) days. CONCLUSIONS: With an asymptomatic phase, disease courses are unexpectedly long until the stage of virus negativity. NP swabs are not reliable in later stages of COVID-19. Pneumonia outlasts virus-positive tests if sputum is not acquired. Imminent pulmonary fibrosis in high-risk groups demands follow-up examinations. Investigation of promising antiviral agents should heed the specific needs of mild and moderate COVID-19 patients.