Clinical characteristics of COVID-19 patients in three consecutive generations of spread in Zhejiang, China

Abstract

Objectives: The aim was to determine the clinical characteristics of COVID-19 patients because the SARS-CoV-2 virus continues to circulate in the population.

Methods: This is a retrospective, multicentre, cohort study. Adult COVID-19 cases from four hospitals in Zhejiang were enrolled and clustered into three groups based on epidemiological history. First-generation patients had a travel history to Hubei within 14 days before disease onset; second-generation patients had a contact history with first-generation patients; third-generation patients had a contact history with second-generation patients. Demographic, clinical characteristics, clinical outcomes and duration of viral shedding were analysed.

Results: A total of 171 patients were enrolled, with 83, 44 and 44 patients in the first-, second-, and third-generation, respectively. Compared with the first and second generations, third-generation patients were older (61.3 vs. 48.3 and 44.0 years, p < 0.001) and had more coexisting conditions (56.8% vs. 36.1% and 27.3%, p 0.013). At 7 ± 1 days from illness onset, third-generation patients had lower lymphocyte (0.6 vs. 0.8 and 0.8 × 109/L, p 0.007), higher C-reactive protein (29.7 vs. 17.1 and 13.8 mg/L, p 0.018) and D-dimer (1066 vs. 412.5 and 549 μg/L, p 0.002) and more lesions involving the pulmonary lobes (lobes ≥5, 81.8% vs. 53.0% and 34.1%, p < 0.001). The proportions of third-generation patients developing severe illness (72.7% vs. 32.5% and 27.3%, p < 0.001), critical illness (38.6% vs. 10.8% and 6.8%, p < 0.001) and receiving endotracheal intubation (20.5% vs. 3.6% and 2.3%, p 0.002) were higher than in the other two groups.

Discussion: Third-generation patients were older, had more underlying comorbidities and had a higher proportion of severe or critical illness than first- and second-generation patients.

Keywords: COVID-19; Clinical characteristics; Epidemiology; SARS-CoV-2; Severity.

Fig. 1

The total number of new patients from the day of illness onset until the end of the study period. No cases were diagnosed from February 18 to March 10, 2020.

Fig. 2

Duration of SARS-CoV-2 viral shedding in the different groups (mean days labelled days). The duration of viral shedding was calculated from the date of disease onset to the date when PCR was negative for viral RNA from nasopharyngeal swabs. The mean duration of viral shedding for the first, second and third generation of patients was 17 (11.0, 24.0) days, 16.5 (12.3, 20.8) days and 18 (13.0, 26.5) days respectively. There were no significant differences between the three groups (p 0.706).