RESEARCH ARTICLE
A Clinical Comparison of Imported or Locally Acquired COVID-19 Suggests Declining Severity after Viral Passages at the Early Stage of the Pandemic in China
Feifei Su1, *, Shoufeng Yang1, Liang Hong2, Yao Sun3, Yue Qu3, 4
Article Information
Identifiers and Pagination:
Year: 2021Volume: 1
First Page: 101
Last Page: 107
Publisher ID: TOCOVIDJ-1-101
DOI: 10.2174/2666958702101010101
Article History:
Received Date: 17/2/2021Revision Received Date: 2/6/2021
Acceptance Date: 16/6/2021
Electronic publication date: 15/10/2021
Collection year: 2021
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Objective:
This retrospective, two-center study aimed to provide solid clinical evidence to support the viral attenuation theory after passages of SARS-CoV-2 during the early stages of the pandemic.
Methods:
Clinical characteristics and outcomes of 150 COVID-19 patients hospitalized in Wenzhou, China between January and April 2020 were compared. These patients had similar demographic characteristics. Infections of 77 patients who visited Wuhan within 14 days before symptom onset were categorized as imported cases and that of the remaining 73 patients who had no recent travel history were categorized as locally transmitted cases.
Results:
COVID-19 cases in Wenzhou appeared to be mostly mild at the early stages of the pandemic. There were no differences in clinical manifestations, laboratory testing results, and radiographic presentation between imported and locally transmitted cases in Wenzhou, except that a higher proportion of lymphopenia was found in the imported case group. Assessment of infection severity showed that severe conditions were observed in 10.7% of the patients, with the imported case group having a significantly higher rate (15.6%) than the locally transmitted case group (5.5%, x2 = 4.016, p = 0.045).
Conclusion:
Although, the clinical manifestations of locally acquired infections were indistinguishable from those imported from Wuhan, they were less likely to develop into severe medical conditions, suggesting the possibility of virulence attenuation after viral passages during the early stages of the pandemic.
