Decreased B Cells on Admission was Associated with Prolonged Virus Shedding from Respiratory Tract in Coronavirus Disease 2019: A Case Control Study
35 Pages Posted: 25 Mar 2020More...
Background: The virus shedding time (VST) of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) was of significant importance in Coronavirus Disease 2019 (COVID-19), for patients with long VST, especially without symptoms, could potentially cause more contagion in community. However, the shedding of SARS-CoV-2 and risk factors for prolonged VST has not well characterized. This report intended to describe the SARS-CoV-2 shedding from respiratory tract and analyze risk factors associated with prolonged VST.
Methods: COVID-19 patients admitted to the First Affiliated Hospital, College of Medicine, Zhejiang University, China from January 19 to February 19, 2020 was included in this retrospective study. The final follow-up was March 3, 2020. Demographic, clinical, laboratory, treatment and outcome data were collected and compared between patients with short and long VST (in the first and last VST interquartile). The RT-PCR detections of SARS-CoV-2 from respiratory tract specimens were carried out daily. Both logistic regression and Cox proportional hazard regression were performed to analyze the risk factors of prolonged VST.
Findings: Of the 104 confirmed and hospitalized COVID-19 patients, the median of VST was 11 (IQR, 7-18) days. There were 7(6.7%) patients had extreme long virus shedding time over 30 days. The probability of positive RT-PCR results in the next test after 1 or 2 consecutive negatives was as high as 30.5% and 16.4% respectively. The probability of recurrent positive RT-PCR results decreased sharply to 4.8% after three consecutive negatives. Twenty-four patients whose VST was less than 7 days were assigned to short VST group, while 25 patients whose VST was longer than 18 days were assigned to long VST group. Male sex, elevated body temperature on admission, short time between onset of illness to RT-PCR confirmation, decreased T cells and B cells counts and elevated IL-10 on admission were associated with prolonged VST. Decreased B cell counts was mostly associated with long VST through sensitive analyses. The VST in patients with normal B cell count was significantly shorter than patients with decreased B cell on admission (median[IQR], 11[9-13] vs 16[12-20] days, P =0.001).
Interpretation: The prolonged VST was partially responsible for the wide spread of COVID-19. At least three consecutive negatives were suitable for the criteria of end of virus shedding. Patients with decreased B cells on admission had longer virus shedding from respiratory tract in Coronavirus Disease 2019.
Funding Statement: This work was supported by National Natural Science Foundation of China (81700549) and National Major Science and Technology Research Projects for the Control and Prevention of Major Infectious Diseases in China (2017ZX10202202).
Declaration of Interests: The authors declare no competing interests.
Ethics Approval Statement: This study was approved by the Clinical Research Ethics Committee of the First Affiliated Hospital, College of Medicine, Zhejiang University (NO. IIT20200005C). Written informed consent was waived by the ethics commission for this retrospective study.
Keywords: B cells; COVID-19; virus shedding; IL-10; T cells
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