Aerosol Release by Healthy People during Speaking: Possible Contribution to the Transmission of SARS-CoV-2

Our research aimed to review the potential risk of infection by SARS-CoV-2. We used an excerpt of a data set generated in May 2020 for reviewing the SARS-CoV-2 prevention concept of orchestras, singers and actors. People were sampled for droplet release for one-hour activities using a Grimm spectrometer covering a spectrum of 1 to 32 µm diameter. We estimated the number of “quanta” in the exhaled liquid from viral concentrations of 106 to 1011/mL, based on the Human Infective Dose 50 of 218 viral particles. We employed the Wells–Riley equation to estimate the risk of infection in typical meeting rooms for a one-hour meeting of 2, 4 and 6 people observing a 2 m distance. The four participating adults released a mean of 1.28 nLm3 while breathing, 1.68 nL/m3 while speaking normally, and two adults released a mean of 4.44 nL/m3 while talking with a raised voice. The combination of 50% breathing, 45% talking normally and 5% speaking with a raised voice increased the risk of infection above 5% for a one-hour meeting of two people. The result is based on 6 quanta released, corresponding to an initial virus concentration of 1000/nL (109/mL) in the fluid of the upper respiratory tract. Our data confirm the importance of using facemasks in combination with other measures to prevent transmission of SARS-CoV-2 at the workplace.

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Biotypes of Candida albicans strains colonizing the upper respiratory tract in healthy people living in Lubelszczyzna

Annales UMCS Pharmacia ◽

10.2478/v10080-008-0015-z ◽

2008 ◽

Vol 21 (1) ◽

pp. 109-112

Author(s):

Agnieszka Grzegorczyk ◽

Anna Biernasiuk ◽

Izabela Mahorowska-Kiciak ◽

Anna Malm

Keyword(s):

Candida Albicans ◽

Respiratory Tract ◽

Healthy People ◽

Upper Respiratory Tract ◽

Upper Respiratory

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A combined oro-nasopharyngeal swab is more sensitive than mouthwash in detecting SARS-CoV-2 by a high-throughput PCR assay

10.1101/2020.09.25.20201541 ◽

2020 ◽

Author(s):

Wiebke Michel ◽

Jacqueline Farber ◽

Milica Dilas ◽

Ina Tammer ◽

Jannik Baar ◽

...

Keyword(s):

Respiratory Tract ◽

Test Performance ◽

Nasopharyngeal Swab ◽

Virus Concentration ◽

Upper Respiratory Tract ◽

Sterile Water ◽

Test Results ◽

Pcr Assay ◽

Previous Diagnosis ◽

Upper Respiratory

Objectives: The optimal diagnostic specimen to detect SARS-CoV-2 by PCR in the upper respiratory tract is unclear. Mouthwash fluid has been reported as an alternative to nasopharyngeal and oropharyngeal swabs. We compared mouthwash fluid with a combined oro-nasopharyngeal swab regarding test performance. Methods: We tested asymptomatic persons with a previous diagnosis of COVID-19 and their household contacts. First, a mouthwash (gargling for at least 5 sec) with sterile water was performed. Then, with a single flocked swab the back of the throat and subsequently the nasopharynx were sampled. Samples were inactivated and analysed on a Roche cobas 6800 system with the Roche SARS-CoV-2 test. Results: Of 76 persons, 39 (51%) tested positive for SARS-CoV-2 by oro-nasopharyngeal swab. Mouthwash detected 13 (17%) of these infections but did not detect any additional infection. Samples that were positive in both tests, had lower cycle threshold (Ct)-values for oro-nasopharyngeal samples, indicating a higher virus concentration, compared to samples only positive in oro-nasopharyngeal swabs. Conclusions: Mouthwash is not as sensitive as combined oro-nasopharyngeal swab in detecting upper respiratory tract infection.

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A combined oro-nasopharyngeal swab is more sensitive than mouthwash in detecting SARS-CoV-2 by a high-throughput PCR assay

Infection ◽

10.1007/s15010-021-01600-1 ◽

2021 ◽

Author(s):

Wiebke Michel ◽

Jacqueline Färber ◽

Milica Dilas ◽

Hans-Gert Heuft ◽

Ina Tammer ◽

...

Keyword(s):

Respiratory Tract ◽

Test Performance ◽

Nasopharyngeal Swab ◽

Virus Concentration ◽

Upper Respiratory Tract ◽

Sterile Water ◽

Pcr Assay ◽

Upper Respiratory ◽

Roche Cobas ◽

Close Contacts

Abstract Objectives The optimal diagnostic specimen to detect SARS-CoV-2 by PCR in the upper respiratory tract is unclear. Mouthwash fluid has been reported as an alternative to nasopharyngeal and oropharyngeal swabs. We compared mouthwash fluid with a combined oro-nasopharyngeal swab regarding test performance. Methods In a large refugee facility, we retested individuals with a previous positive test for SARS-CoV-2 and their quarantined close contacts. All individuals were asymptomatic at the time of testing. First, a mouthwash (gargling for at least 5 s) with sterile water was performed. Then, with a single flocked swab the back of the throat and subsequently the nasopharynx were sampled. Samples were inactivated and analysed on a Roche cobas 6800® system with the Roche SARS-CoV-2 test. Results Of 76 individuals, 39 (51%) tested positive for SARS-CoV-2 by oro-nasopharyngeal swab. Mouthwash detected 13 of 76 (17%) infections, but did not detect any additional infection. Samples that were positive in both tests, had lower cycle threshold (Ct)-values for oro-nasopharyngeal samples, indicating a higher virus concentration, compared to samples only positive in oro-nasopharyngeal swabs. Conclusion Mouthwash is not as sensitive as combined oro-nasopharyngeal swab in detecting upper respiratory tract infection.

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