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6th Edition of World Congress on Infectious Diseases

June 24-26, 2024 | Paris, France

June 24 -26, 2024 | Paris, France
Infection 2024

Liu Yen Hung

Speaker at Infection Conference - Liu Yen Hung
Cardinal Tien Hospital, Taiwan
Title : Dynamics of SARS-CoV-2 shedding in the nasopharyngeal samples in hospitalized COVID-19 patients


Introduction: SARS-CoV-2 has spread worldwide and dramatically and devastatingly impacted our society. Quarantine has been taken to slow down its spread. Due to some adverse impacts on individuals and communities caused by quarantine, other interventions, such as vaccination and anti-viral agents, were suggested to replace the quarantine. However, the effectiveness of these interventions has been widely discussed as it was affected by many factors, including age, vaccination status, severity of COVID-19, and SARS-CoV-2 variants. In this study, we aimed to investigate some factors that determine the clearance of SARS-CoV2 in the setting of the real world.

Methods: Adults aged ≥ 18 years with SARS-CoV-2 infection and hospitalized in the Cardinal Tien Hospital between January 1 and July 31,2022 were enrolled. Patients who admitted to intensive care units were excluded. The following information was collected : age, the date of confirmed SARS-CoV-2 infection, COVID-19 vaccination history(mRNA or non-mRNA vaccines), Ct values of SARS-CoV-2 PCR and the drug prescriptions of metformin and statins. The time interval between the date of confirmed SARS-CoV-2 infection and the date of last dose of SARS-CoV-2 vaccine was calculated and recorded. The date of clearance of SARS-CoV-2 shedding, defined as negative results or Ct value ≥ 30 of SARS-CoV-2 PCR through nasopharyngeal swabs, were also collected. For AZD1222 (AstraZeneca), BNT162b2 (Pfizer–BioNTech), mRNA-1273 (Moderna), NVX-CoV23373(Novavax), and MVC-COV1901(Medigen) ,vaccination status at the time of confirmed SARS-CoV-2 infection was categorized into three groups and defined as (A) fully vaccinated (≥14 days had elapsed since the second vaccine dose), (B) partially vaccinated (>21 days had elapsed since the first vaccine dose, but <14 days after the second dose) and (C) insufficiently vaccinated (<22 days had elapsed since the first vaccine dose). For Ad26.COV2.S (Johnson & Johnson–Janssen), fully and partially vaccinated status were defined as ≥14 days and <14 days elapsed since the vaccine dose, respectively.

Results: 308 COVID-19 patients (mean age:66.9) were enrolled in this study and 53.6%, 11.4%, and 34.4% were fully, partially, and insufficiently vaccinated, respectively. Ct value ≥ 30 of SARS-CoV-2 PCR were available in 299 patients at a mean day of 9.5 after confirmation of SARS-CoV-2 infection. Only 19 patients (6.17%) used metformin while 18 patients(5.84%) were treated with statins. Faster clearance of RNA viral loads were noted in patients aged < 65 years. Neither vaccination status, vaccine types, metformin, nor statins affect the clearance of SARS-CoV-2 shedding.

Conclusion: Age affects the clearance of SARS-CoV-2 shedding. Vaccination status, vaccine types, metformin, and statins make no difference in the dynamics of SARS-CoV-2 shedding.


Dr. Liu Yen-Hung studied Medicine at China Medical University, Taiwan and graduated as MD in 2003. He then completed the residency training of internal medicine at Taipei Veteran General Hospital, Taiwan in 2010. After that, he has worked as an infection specialist in Cardinal Tien Hospital, Taiwan now. He also got involved in the clinical researches in infectious diseases at National Taiwan University and received his PhD degree in 2020 at the same institution. His researches focus on HIV, STD and antimicrobial resistance.