Updated guidance for infection prevention and control in health care settings when COVID-19 is suspected or confirmed – April 2024

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This document updates the previous guidance document "Update with consideration of omicron: Interim COVID-19 infection prevention and control in the healthcare setting when COVID-19 is suspected or confirmed-December 23, 2021" with revised recommendations for:


This document, which updates previous national Infection Prevention and Control (IPC) guidance developed for health care settings for IPC interventions to prevent and control COVID-19, was informed using expert advice from the National Advisory Committee on Infection Prevention and Control (NAC-IPC), by reviewing available scientific evidence and completion of an environmental scan of international, provincial and territorial guidance.

For the purposes of this document, the term "patient" includes persons receiving health care who are traditionally/routinely referred to as patients, clients or residents.

Risk and transmission

SARS-CoV-2 proved to be a rapidly mutating virus, with the development of multiple variants impacting transmissibility, and vaccine effectiveness. Factors affecting the risk of acquisition of healthcare-associated SARS-CoV-2 infections include:

Respiratory particles (respiratory droplets and small aerosol particlesFootnote a) continue to be the primary source of transmission for SARS-CoV-2. Infections can occur when respiratory mucosa (eyes, nose or mouth) are exposed to infectious respiratory particles. Individuals who are infected with SARS-CoV-2 virus can release infectious respiratory particles in a range of sizes when talking, breathing, singing, exercising, coughing, sneezing. These particles can remain suspended in the air and be inhaled into the respiratory tract of another person and cause infection. It is also assumed that some degree of contact transmission occurs through contaminated surfaces or objects.

Aim and scope

The Public Health Agency of Canada (PHAC) develops national evidence-informed IPC guidance to complement provincial and territorial public health efforts in monitoring, preventing, and controlling healthcare-associated infections. Guidance will evolve with new scientific evidence, as well as with careful consideration of implications for practice in areas of uncertainty. National-level guidance should always be used in conjunction with relevant provincial, territorial and local policies and regulations. PHAC guidance does not supersede provincial, territorial, and local policies and regulations. PHAC will continue to consider new evidence as it becomes available. This guidance is for all healthcare settings (acute care, long-term care, home care and ambulatory/outpatient care). For guidance on public health measures for COVID-19, please refer to Coronavirus disease (COVID-19) - Canada.ca

Hierarchy of controls

Continue to implement and re-evaluate the hierarchy of controls within the healthcare environment including:

Engineering controls

Administrative controls

Screening and surveillance

Patient placement and accommodation

A patient who is suspected or confirmed to have COVID-19 should be cared for in a single room, on precautions with a toilet and sink designated for their use. If no single rooms are available, cohorting patients with confirmed COVID-19 could be considered in consultation with IPC. All facilities should have a pre-established cohorting plan.

Clear signage (universal infographics/multilingual as required) indicating Droplet and Contact precautions with appropriate PPE (for COVID-19) should be in place, and posted in such a way that is clearly visible to all entering the patient room or bed space.
Posters illustrating the correct method for donning on and doffing PPE should be considered for display inside and outside of each room of a patient who is suspected or confirmed to have COVID-19 for easy visual cues.

Personal protective equipment

Recommended PPE for all patient encounters should be based on a Point of Care Risk Assessment (PCRA) which should include consideration of:

Recommended PPE for direct care of patients with suspected or confirmed COVID-19:

Every HCW should have access to a fit-tested respirator, so that they can put it on quickly if the need is identified during the PCRA.

Consider implementing universal use of respirators for all HCWs during all patient care encounters in specific units or areas of facility at higher risk of SARS-CoV-2 transmission, e.g., COVID-19 designated units, emergency departments, open space critical care areas, areas with high frequency of aerosol-generating medical procedures (AGMPs), etc.

Routine practices and additional precautions

Routine practices, including hand hygiene, are in place for the care of all patients. In addition to routine practices, droplet and contact precautions with appropriate PPE for COVID-19 should be used when caring for patients with suspected or confirmed COVID-19. Please refer to PHAC's Routine Practices and Additional Precautions for Preventing the Transmission of Infection in Healthcare Settings (2013) guidance document.

Information should be provided to staff, visitors, and patients who are asked to wear a respirator or medical mask about the importance of performing hand hygiene prior to putting on, and after removing or touching their mask, to reduce risk of self-contamination.

Individuals should also be informed about the steps for proper hand hygiene, and that wearing a respirator or medical mask does not lessen the need to adhere to other measures to reduce SARS-CoV-2 transmission.

Communication materials for visitors should consider the needs of diverse populations such as those with disabilities and those who may not be fluent in either English or French.

Aerosol exposure and aerosol-generating medical procedures (AGMPs)

Historically, certain medical procedures, known as AGMPs, were thought to pose a higher risk for HCWs on the basis of case–control studies, mainly from SARS-CoV-1, which reported associations between selected procedures and HCW infections. As evidence is evolving it remains prudent to continue to use fit-tested, seal-checked N95 respirators, eye protection, gowns and gloves for all AGMPs on patients with suspected or confirmed COVID-19.

Discontinuation of additional precautions

The duration and discontinuation of additional precautions for an individual patient or unit (where precautions may be universally applied during a COVID-19 outbreak) should be determined on a case-by-case basis, in consultation with the IPC program and in accordance with local, provincial or territorial public health guidance and organizational policies. The duration of additional precautions for a symptomatic patient with COVID-19 should be for a minimum of 10 days from onset of symptoms (and a minimum of 10 days from first positive testing for patients who remain asymptomatic), and may be longer dependent upon duration of symptoms, disease severity and the presence of any underlying immunocompromising conditions.

Masking for source control

Medical masks can be worn by HCWs, staff, patients, visitors, caregivers, and any other individual present in the healthcare setting for the purpose of protecting others by preventing the spread of bacteria and virus to others. This is known as masking for source control. This can be applied at the individual level (e.g., individual with respiratory signs or symptoms) or more broadly (e.g., all HCWs, visitors, and patients). Masks used for the purpose of source control should be of medical grade and well-fitting.

Individual masking for source control

Broader masking for source control

If implementing broad masking for source control, consider the impact on persons with cognitive impairment or where masks could impede communication or otherwise hinder the ability to provide equitable care.

Implementation of broad source masking may vary based on jurisdictional and facility-specific context, including organizational risk assessment.

Patients who are unable or unwilling to mask should not be denied care. Protocols should be in place to allow for the safe assessment and treatment of symptomatic, unmasked patients. Patient masking is not recommended for paediatric patients two years of age or younger or for any patient unable to tolerate masking for medical or developmental reasons.


Visitation policies and restrictions may vary across jurisdictions and facilities depending on the degree of local transmission of SARS-CoV-2. Policies should aim to balance the risk of introduction and transmission of SARS-CoV-2, and the promotion of patient and family-centered care including physical, psychological, emotional and spiritual needs of patients.

Visitors exhibiting signs or symptoms of an acute respiratory infection, including COVID-19, should not enter the facility. However, if visitation is required (e.g., end of life decisions), refer to institutional policies and procedures.

IPC information including the importance of adherence to IPC measures should be provided to visitors.

Communication materials for patients and visitors should address the needs of diverse populations such as those with disabilities and those who may not be fluent in either English or French.


Footnote 1

There is a transition away from the use of the terms "droplet" and "aerosol" as evidence suggests that respiratory particles exist on a continuum of sizes. As these terms are still commonly used in practice, they are included for clarity and to ensure appropriate application of IPC precautions.

Return to footnote a referrer


  1. Adenaiye, O. O., Lai, J., Bueno de Mesquita, P. J., Hong, F., Youssefi, S., German, J., Tai, S. H. S., Albert, B., Schanz, M., Weston, S., Hang, J., Fung, C., Chung, H. K., Coleman, K. K., Sapoval, N., Treangen, T., Berry, I. M., Mullins, K., Frieman, M.,... Milton, D. K. (2022). Infectious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Exhaled Aerosols and Efficacy of Masks During Early Mild Infection. Clinical Infectious Diseases, 75(1), e241-e248. 10.1093/cid/ciab797
  2. Alexander Wilhelm, Marek Widera, Katharina Grikscheit, Tuna Toptan, Barbara Schenk, Christiane Pallas, Melinda Metzler, Niko Kohmer, Sebastian Hoehl, Fabian A. Helfritz, Timo Wolf, Udo Goetsch, & Sandra Ciesek. (2021). Reduced Neutralization of SARS-CoV-2 Omicron Variant by Vaccine Sera and monoclonal antibodies. medRxiv,, 2021.12.07.21267432. 10.1101/2021.12.07.21267432
  3. Alghounaim, M., Caya, C., Alothman, K., Alhasawi, A., & Papenburg, J. (2022). SARS-CoV-2 Clinical Characteristics and Viral Shedding in Kuwait. Medical Principles and Practice, 31(1), 93-97. 10.1159/000521408
  4. Alsved, M., Matamis, A., Bohlin, R., Richter, M., Bengtsson, P. -., Fraenkel, C. -., Medstrand, P., & Löndahl, J. (2020). Exhaled respiratory particles during singing and talking. Aerosol Science and Technology, 54(11), 1245-1248. 10.1080/02786826.2020.1812502
  5. Arai, T., Mukai, S., Kazama, R., Ogawa, Y., Nishida, K., Hatanaka, K., & Gohma, I. (2022). Persistent viral shedding of severe acute respiratory syndrome coronavirus 2 after treatment with bendamustine and rituximab: A case report. Journal of Infection and Chemotherapy : Official Journal of the Japan Society of Chemotherapy, 28(6), 810-813. 10.1016/j.jiac.2022.01.014
  6. Asadi, S., Wexler, A. S., Cappa, C. D., Barreda, S., Bouvier, N. M., & Ristenpart, W. D. (2019). Aerosol emission and superemission during human speech increase with voice loudness. Springer Science and Business Media LLC. 10.1038/s41598-019-38808-z
  7. Asadi, S., Wexler, A. S., Cappa, C. D., Barreda, S., Bouvier, N. M., & Ristenpart, W. D. (2020). Effect of voicing and articulation manner on aerosol particle emission during human speech. Public Library of Science (PLoS).
  8. Batra, A., Clark, J. R., Kang, A. K., Ali, S., Patel, T. R., Shlobin, N. A., Hoffman, S. C., Lim, P. H., Orban, Z. S., Visvabharathy, L., Graham, E. L., Sullivan, D. P., Muller, W. A., Chou, S. H. -., Ungvári, Z., Koralnik, I. J., & Liotta, E. M. (2022). Persistent viral RNA shedding of SARS-CoV-2 is associated with delirium incidence and six-month mortality in hospitalized COVID-19 patients. GeroScience, 44(3), 1241-1254. 10.1007/s11357-022-00561-z
  9. Bourouiba, L. (2020). Turbulent Gas Clouds and Respiratory Pathogen Emissions
    Potential Implications for Reducing Transmission of COVID-19. JAMA Insights, 323(18)10.1001/jama.2020.4756
  10. Brooks, J., Beezhold, D., Noti, J., Coyle, J., Derk, R., Blanchere, F., & Lindsley, W. (2021). Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021. Morbidity and Morality Weekly Report, 70(7) https://www.cdc.gov/mmwr/volumes/70/wr/mm7007e1.htm
  11. Brown, J., Gregson, F. K. A., Shrimpton, A., Cook, T. M., Bzdek, B. R., Reid, J. P., & Pickering, A. E. (2020). A quantitative evaluation of aerosol generation during tracheal intubation and extubation. Wiley. 10.1111/anae.15292
  12. Buonanno, G., Stabile, L., & Morawska, L. (2020). Estimation of airborne viral emission: Quanta emission rate of SARS-CoV-2 for infection risk assessment. Https://Pubmed.Ncbi.Nlm.Nih.Gov/32416374/, 10.1016/j.envint.2020.105794
  13. Chan, P., & Fang, C. (2020). The role of ventilation in tuberculosis control.120(6)10.1016/j.jfma.2020.11.003
  14. Chan, V., Hoi-Lam Ng, H., Rahman, L., Tang, A., Tange, K., Mok, A., Lui, J., Ho, K., Chan, S., Wong, S., Teoh, A., Chan, A., Wong, M., Yuan, Y., & Teoh, J. (2021). Transmission of Severe Acute Respiratory Syndrome Coronavirus 1 and Severe Acute Respiratory Syndrome Coronavirus 2 During Aerosol-Generating Procedures in Critical Care: A Systematic Review and Meta-Analysis of Observational Studies.49(7)10.1097/CCM.0000000000004965
  15. Chen, W., Ling, W., Lu, C., Hao, Y., Lin, Z., Ling, L., Huang, J., Li, G., & Yan, G. (2009). Which preventive measures might protect health care workers from SARS? BMC Public Health, https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-9-81#citeas
  16. Chen, W., Zhang, N., Wei, J., Yen, H., & Li, Y. (2020). Short-range airborne route dominates exposure of respiratory infection during close contact. Building and Environment, 176, 106859. 10.1016/j.buildenv.2020.106859
  17. Cheng, V. C., Fung, K. S., Siu, G. K., Wong, S. C., Cheng, L. S., Wong, M. S., Lee, L. K., Chan, W. M., Chau, K. Y., Leung, J. S., Chu, A. W., Chan, W. S., Lu, K. K., Tam, K. K., Ip, J. D., Leung, K. S., Lung, D. C., Tse, H., To, K. K., & Yuen, K. Y. (2021). Nosocomial Outbreak of Coronavirus Disease 2019 by Possible Airborne Transmission Leading to a Superspreading Event. Clinical Efectious Diseases, 76(6) https://doi.org/10.1093/cid/ciab313
  18. Chopoorian, A., Banada, P., Reiss, R., Elson, D., Desind, S., Park, C., Banik, S., Hennig, E., Wats, A., Togba, A., Wei, A., Daivaa, N., Palo, L., Hirsch, M., Campbell, C., Saiganesh, P., Alland, D., & Xie, Y. L. (2023). Persistence of SARS-CoV-2 in saliva: Implications for late-stage diagnosis and infectious duration. Public Library of Science (PLoS). 10.1371/journal.pone.0282708
  19. Coleman, K. K., Tay, D. J. W., Tan, K. S., Ong, S. W. X., Than, T. S., Koh, M. H., Chin, Y. Q., Nasir, H., Mak, T. M., Chu, J. J. H., Milton, D. K., Chow, V. T. K., Tambyah, P. A., Chen, M., & Tham, K. W.Viral Load of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Respiratory Aerosols Emitted by Patients With Coronavirus Disease 2019 (COVID-19) While Breathing, Talking, and Singing. Clinical Efectious Diseases, 74(10), 1722-1728. https://doi.org/10.1093/cid/ciab691
  20. Crawford, C., Vanoli, E., Decorde, B., Lancelot, M., Duprat, C., Josserand, C., Jilesen, J., Bouadma, L., & Timsit, J. F. (2021). Modeling of aerosol transmission of airborne pathogens in ICU rooms of COVID-19 patients with acute respiratory failure. Scientific Reports, 118(1), 11778. https://doi.org/10.1038/s41598-021-91265-5
  21. Doung-Ngern, P., Suphanchaimat, R., Panjangampatthana, A., Janekrongtham, C., Ruampoom, D., Daochaeng, N., Eungkanit, N., Pisitpayat, N., Srisong, N., Yasopa, O., Plernprom, P., Promduangsi, P., Kumphon, P., Suangtho, P., Watakulsin, P., Chaiya, S., Kripattanapong, S., Chantian, T., Bloss, E., Namwat, C., … Limmathurotsakul, D. (2020). Case-Control Study of Use of Personal Protective Measures and Risk for SARS-CoV 2 Infection. Emerging Infectious Diseases, 26(11), 2607–2616. https://doi.org/10.3201/eid2611.203003
  22. Echternach, M., Gantner, S., Peters, G., Westphalen, C., Benthaus, T., Jakubaß, B., Kuranova, L., Döllinger, M., & Kniesburges, S. (2020). Impulse Dispersion of Aerosols during Singing and Speaking: A Potential COVID-19 Transmission Pathway. American Journal of Respiratory and Critical Care Medicine, 202(11), 1584–1587. https://doi.org/10.1164/rccm.202009-3438LE
  23. Edwards, D. A., Ausiello, D., Salzman, J., Devlin, T., Langer, R., Beddingfield, B. J., Fears, A. C., Doyle-Meyers, L. A., Redmann, R. K., Killeen, S. Z., Maness, N. J., & Roy, C. J. (2021). Exhaled aerosol increases with COVID-19 infection, age, and obesity. Proceedings of the National Academy of Sciences of the United States of America, 118(8) https://doi.org/10.1073/pnas.2021830118
  24. European Centre for Disease Control. (2023). Implications for the EU/EEA of the spread of the
    SARS-CoV-2 Omicron XBB.1.5 sub-lineage. https://www.ecdc.europa.eu/sites/default/files/documents/TAB-Implications%20for%20the%20EU-EEA%20of%20the%20spread%20of%20the%20SARS-CoV-2%20Omicron%20XBB.1.5%20sub-lineage.pdf
  25. Fennelly, K. P. (2020). Particle sizes of infectious aerosols: implications for infection control. The Lancet, 8(9), 914-924. https://doi.org/10.1016/S2213-2600(20)30323-4
  26. Gaeckle, N. T., Lee, J., Park, Y., Kreykes, G., Evans, M. D., & Hogan, C. J., Jr. (2020). Aerosol Generation from the Respiratory Tract with Various Modes of Oxygen Delivery. American Journal of Respiratory and Critical Care Medicine, 202(8), 1115–1124. https://doi.org/10.1164/rccm.202006-2309OC
  27. Goldberg, L., Levinsky, Y., Marcus, N., Hoffer, V., Gafner, M., Hadas, S., Kraus, S., Mor, M., & Scheuerman, O. (2021). SARS-CoV-2 Infection Among Health Care Workers Despite the Use of Surgical Masks and Physical Distancing-the Role of Airborne Transmission. Open Forum Infectious Diseases, 8(3) https://doi.org/10.1093/ofid/ofab036
  28. Greenhalgh, T., Jimenez, J. L., Prather, K. A., Tufekci, Z., Fisman, D., & Schooley, R. (2021). Ten scientific reasons in support of airborne transmission of SARS-CoV-2. Lancet (London, England), 397(10285), 1603–1605. https://doi.org/10.1016/S0140-6736(21)00869-2
  29. Hamner, L., Dubbel, P., Capron, I., Ross, A., Jordan, A., Lee, J., Lynn, J., Ball, A., Narwal, S., Russell, S., Patrick, D., & Leibrand, H. (2020). High SARS-CoV-2 Attack Rate Following Exposure at a Choir Practice - Skagit County, Washington, March 2020. Morbidity and Morality Weekly Report, 69(19), 606-610. https://doi.org/10.15585/mmwr.mm6919e6
  30. Hause, A. M., Baggs, J., Marquez, P., Myers, T. R., Gee, J., Su, J. R., Zhang, B., Thompson, D., Shimabukuro, T. T., Shay, D. K., Walensky, R. P., Houry, D., Jernigan, D. B., Bunnell, R., Layden, J., & Iademarco, M. F.COVID-19 Vaccine Safety in Children Aged 5-11 Years -United States, November 3-December 19, 2021
  31. He, S., Fang, Y., Yang, J., & Wang, W. (2022). Association between immunity and viral shedding duration in non-severe SARS-CoV-2 Omicron variant-infected patients.10.3389/978-2-8325-2252-3
  32. Huang, J., Shen, H., Sun, C., Chen, W., Chen, Y., Feng, J., & Yang, K. (2022). COVID-19-associated pulmonary aspergillosis is associated with increased in-hospital mortality and prolonged SARS-CoV-2 viral shedding. Journal of the Formosan Medical Association, 121(12), 2617-2625. 10.1016/j.jfma.2022.07.006
  33. Huang, P., Wu, T., Cheng, C., Chen, C., Huang, C., Tsao, K., Lin, C., Chung, T., Lai, C., Yang, C. -. T., Chen, Y., Chiu, C., Huang, L., Chiu, Y., Hou, K., Chen, M., Huang, Y., Tsai, L., Su, Y.,... Wu, Y. (2022). A hospital cluster of COVID-19 associated with a SARS-CoV-2 superspreading event. Journal of Microbiology, Immunology and Infection, 55(3), 436-444. 10.1016/j.jmii.2021.07.006
  34. Jacob, J. T., Baker, J. M., Fridkin, S. K., Lopman, B. A., Steinberg, J. P., Christenson, R. H., King, B., Leekha, S., O'Hara, L. M., Rock, P., Schrank, G. M., Hayden, M. K., Hota, B., Lin, M. Y., Stein, B. D., Caturegli, P., Milstone, A. M., Rock, C., Voskertchian, A., Reddy, S. C., … Harris, A. D. (2021). Risk Factors Associated With SARS-CoV-2 Seropositivity Among US Health Care Personnel. JAMA Network Open, 4(3) https://doi.org/10.1001/jamanetworkopen.2021.1283
  35. Jefferson, T., Spencer, E. A., Conly, J. M., Rosca, E. C., Maltoni, S., Brassey, J., Onakpoya, I. J., Evans, D. H., Heneghan, C. J., & Plüddemann, A. (2023). Viral cultures, cycle threshold values and viral load estimation for assessing SARS-CoV-2 infectiousness in haematopoietic stem cell and solid organ transplant patients: a systematic review. The Journal of Hospital Infection, 132, 62-72. 10.1016/j.jhin.2022.11.018
  36. Johansson, M. A., Quandelacy, T. M., Kada, S., Prasad, P. V., Steele, M., Brooks, J. T., Slayton, R. B., Biggerstaff, M., & Butler, J. C. (2021). SARS-CoV-2 Transmission From People Without COVID-19 Symptoms. JAMA Network Open, 4(1), e2035057. 10.1001/jamanetworkopen.2020.35057
  37. Jung, J., Kim, J. Y., Park, H., Park, S., Lim, J. S., Lim, S. Y., Bae, S., Lim, Y., Kim, E. O., Kim, J., Park, M., & Kim, S. (2022a). Transmission and Infectious SARS-CoV-2 Shedding Kinetics in Vaccinated and Unvaccinated Individuals. JAMA Network Open, 5(5), e2213606. 10.1001/jamanetworkopen.2022.13606
  38. Jung, J., Lee, J., Kim, S., Park, S., Lim, Y., Kim, E. O., Park, H., Park, M., & Kim, S. (2022b). Evaluation of In-Hospital Cluster of COVID-19 Associated With a Patient With Prolonged Viral Shedding Using Whole-Genome Sequencing. Journal of Korean Medical Science, 37(39), e289. 10.3346/jkms.2022.37.e289
  39. Kang, S. W., Park, H., Kim, J. Y., Park, S., Lim, S. Y., Lee, S., Bae, J., Kim, J., Bae, S., Jung, J., Kim, M. J., Chong, Y. P., Lee, S., Choi, S., Kim, Y. S., Yun, S., Park, M., & Kim, S. (2022). Clinical scoring system to predict viable viral shedding in patients with COVID-19. Journal of Clinical Virology, 157, 105319. 10.1016/j.jcv.2022.105319
  40. Kang, S., Kim, J. Y., Park, H., Lim, S. Y., Kim, J., Chang, E., Bae, S., Jung, J., Kim, M. J., Chong, Y. P., Lee, S., Choi, S., Kim, Y. S., Park, M., & Kim, S. (2022). Comparison of secondary attack rate and viable virus shedding between patients with SARS‐CoV‐2 Delta and Omicron variants: A prospective cohort study. Wiley. 10.1002/jmv.28369
  41. Karan, A., Klompas, M., Tucker, R., Baker, M., Vaidya, V., & Rhee, C. (2022). The Risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission from Patients With Undiagnosed Coronavirus Disease 2019 (COVID-19) to Roommates in a Large Academic Medical Center. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America, 74(6), 1097-1100. 10.1093/cid/ciab564
  42. Kawasuji, H., Takegoshi, Y., Kaneda, M., Ueno, A., Miyajima, Y., Kawago, K., Fukui, Y., Yoshida, Y., Kimura, M., Yamada, H., Sakamaki, I., Tani, H., Morinaga, Y., & Yamamoto, Y. (2020). Transmissibility of COVID-19 depends on the viral load around onset in adult and symptomatic patients. PloS One, 15(12), e0243597. 10.1371/journal.pone.0243597
  43. Kaya, B. S., Yılmam, İ, Çakır Edis, E., Karabulut, D., Elmaslar Mert, T., Eryıldız, C., & Demir, M. (2022). Case of Prolonged Viral Shedding: Chronic, Intermittan COVID-19? Turkish Thoracic Journal, 23(1), 85-88. 10.5152/TurkThoracJ.2022.21141
  44. Kim, D. Y., Lin, M. Y., Jennings, C., Li, H., Jung, J. H., Moore, N. M., Ghinai, I., Black, S. R., Zaccaro, D. J., Brofman, J., & Hayden, M. K. (2022). Duration of Replication-Competent Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Shedding Among Patients With Severe or Critical Coronavirus Disease 2019 (COVID-19). Oxford University Press (OUP). 10.1093/cid/ciac405
  45. Klompas, M., Baker, M. A., Griesbach, D., Tucker, R., Gallagher, G. R., Lang, A. S., Fink, T., Cumming, M., Smole, S., Madoff, L. C., & Rhee, C. (2021a). Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) From Asymptomatic and Presymptomatic Individuals in Healthcare Settings Despite Medical Masks and Eye Protection. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America, 73(9), 1693-1695. 10.1093/cid/ciab218
  46. Klompas, M., Baker, M. A., Rhee, C., Tucker, R., Fiumara, K., Griesbach, D., Bennett-Rizzo, C., Salmasian, H., Wang, R., Wheeler, N., Gallagher, G. R., Lang, A. S., Fink, T., Baez, S., Smole, S., Madoff, L., Goralnick, E., Resnick, A., Pearson, M.,... Morris, C. A. (2021b). A SARS-CoV-2 Cluster in an Acute Care Hospital. Annals of Internal Medicine, 174(6), 794-802. 10.7326/M20-7567
  47. Klompas, M., Baker, M., & Rhee, C. (2021c). What Is an Aerosol-Generating Procedure? JAMA Surgery, 156(2), 113-114. 10.1001/jamasurg.2020.6643
  48. Klompas, M., Ye, S., Vaidya, V., Ochoa, A., Baker, M. A., Hopcia, K., Hashimoto, D., Wang, R., & Rhee, C. (2022). Association Between Airborne Infection Isolation Room Utilization Rates and Healthcare Worker Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infections in 2 Academic Hospitals. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America, 74(12), 2230-2233. 10.1093/cid/ciab849
  49. Kuznetsova, N. A., Ogarkova, D. A., Gushchin, V. A., Antipyat, N. А, Bacalin, V. V., Burgasova, O. A., Vasilchenko, L. A., Samkov, A. A., Simakova, Y. V., Divisenko, E. V., Siniavin, A. E., Tkachuk, A. P., Kolobukhina, L. V., Shidlovskaya, E. V., Tyurin, I. N., Kruzhkova, I. S., Zlobin, V. I., Nikiforova, M. A., Odnoralov, M. A., & Gintsburg, A. L. (2023). Evaluation of the dynamics of detection of viable SARS-CoV-2 (Coronaviridae: Betacoronavirus: Sarbecovirus) in biological samples obtained from patients with COVID-19 in a health care setting, as one of the indicators of the infectivity of the virus. Voprosy Virusologii, 68(2), 105-116. 10.36233/0507-4088-160
  50. Lee, J., Yun, K. W., Jeong, H., Kim, B., Kim, M. J., Park, J. H., Shin, H. S., Oh, H. S., Sung, H., Song, M. G., Cho, S. I., Kim, S. Y., Kang, C. K., Choe, P. G., Park, W. B., Kim, N. J., Oh, M., Choi, E. H., Park, S.,... Seong, M. (2022). SARS-CoV-2 shedding dynamics and transmission in immunosuppressed patients. Virulence, 13(1), 1242-1251. 10.1080/21505594.2022.2101198
  51. Lee, L. Y. W., Rozmanowski, S., Pang, M., Charlett, A., Anderson, C., Hughes, G. J., Barnard, M., Peto, L., Vipond, R., Sienkiewicz, A., Hopkins, S., Bell, J., Crook, D. W., Gent, N., Walker, A. S., Peto, T. E. A., & Eyre, D. W. (2022). Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infectivity by Viral Load, S Gene Variants and Demographic Factors, and the Utility of Lateral Flow Devices to Prevent Transmission. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America, 74(3), 407-415. 10.1093/cid/ciab421
  52. Leung, N. H. L. (2021). Transmissibility and transmission of respiratory viruses. Nature Reviews.Microbiology, 19(8), 528-545. 10.1038/s41579-021-00535-6
  53. Leung, N. H. L., Chu, D. K. W., Shiu, E. Y. C., Chan, K., McDevitt, J. J., Hau, B. J. P., Yen, H., Li, Y., Ip, D. K. M., Peiris, J. S. M., Seto, W., Leung, G. M., Milton, D. K., & Cowling, B. J. (2020). Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Medicine, 26(5), 676-680. 10.1038/s41591-020-0843-2
  54. Leung, N. H. L., Xu, C., Ip, D. K. M., & Cowling, B. J. (2015). Review Article: The Fraction of Influenza Virus Infections That Are Asymptomatic: A Systematic Review and Meta-analysis. Epidemiology (Cambridge, Mass.), 26(6), 862-872. 10.1097/EDE.0000000000000340
  55. Leung, W. F., Chorlton, S., Tyson, J., Al-Rawahi, G. N., Jassem, A. N., Prystajecky, N., Masud, S., Deans, G. D., Chapman, M. G., Mirzanejad, Y., Murray, M. C. M., & Wong, P. H. P. (2022). COVID-19 in an immunocompromised host: persistent shedding of viable SARS-CoV-2 and emergence of multiple mutations: a case report. International Journal of Infectious Diseases, 114, 178-182. 10.1016/j.ijid.2021.10.045
  56. Li, R., Jin, C., Zhang, L., Kong, D., Hu, K., Xuan, M., Liu, Q., Li, S., Zhang, K., & Xue, Y. (2023). Clinical characteristics and risk factors analysis of viral shedding time in mildly symptomatic and asymptomatic patients with SARS-CoV-2 Omicron variant infection in Shanghai. Environ Earth Sci, 10.3389/fpubh.2022.1073387
  57. Li, Z., Zhong, Q., Li, W., Zhang, D., Wang, W., Yang, F., & He, K. (2022). Clinical characteristics of patients with confirmed and asymptomatic SARS-CoV-2 infection in China. PloS One, 17(8), e0273150. 10.1371/journal.pone.0273150
  58. Lindsley, W. G., Derk, R. C., Coyle, J. P., Martin, S. B. J., Mead, K. R., Blachere, F. M., Beezhold, D. H., Brooks, J. T., Boots, T., & Noti, J. D. (2021). Efficacy of Portable Air Cleaners and Masking for Reducing Indoor Exposure to Simulated Exhaled SARS-CoV-2 Aerosols - United States, 2021. MMWR.Morbidity and Mortality Weekly Report, 70(27), 972-976. 10.15585/mmwr.mm7027e1
  59. Liu, K., Yang, X., Feng, C., Chen, M., Zhang, C., & Wang, Y. (2022). Clinical features and independent predictors for recurrence of positive SARS‐CoV‐2 RNA: A propensity score‐matched analysis. Journal of Medical Virology, 94(4), 1402-1411. 10.1002/jmv.27450
  60. Liu, W., Tang, F., Fang, L., De Vlas, S. J., Ma, H., Zhou, J., Looman, C. W. N., Richardus, J. H., & Cao, W. (2009). Risk factors for SARS infection among hospital healthcare workers in Beijing: a case control study. Tropical Medicine & International Health, 14(Suppl 1), 52-59. 10.1111/j.1365-3156.2009.02255.x
  61. Loeb, M., McGeer, A., Henry, B., Ofner, M., Rose, D., Hlywka, T., Levie, J., McQueen, J., Smith, S., Moss, L., Smith, A., Green, K., & Walter, S. D. (2004). SARS among critical care nurses, Toronto. Emerging Infectious Diseases, 10(2), 251-255. 10.3201/eid1002.030838
  62. Loudon, R. G., & Roberts, R. M. (1967). Droplet expulsion from the respiratory tract. The American Review of Respiratory Disease, 95(3), 435-442. 10.1164/arrd.1967.95.3.435
  63. Ma, H., Wang, H., Fang, L., Jiang, J., Wei, M., Liu, W., Zhao, Q., Ma, J., & Cao, W. (2004). A case-control study on the risk factors of severe acute respiratory syndromes among health care workers. Zhonghua Liu Xing Bing Xue Za Zhi = Zhonghua Liuxingbingxue Zazhi, 25(9), 741-744.
  64. Maan, I., Paraskevopoulou, S. M., Cwynarski, K., Shrestha, M., Waters, L., Miller, R., & Ahmed, N. (2022). Prolonged SARS-CoV-2 shedding in a person living with advanced HIV and diffuse large B-cell lymphoma: a case report. Informa UK Limited. 10.1080/23744235.2022.2055136
  65. Marks, M., Millat-Martinez, P., Ouchi, D., Roberts, C. H., Alemany, A., Corbacho-Monné, M., Ubals, M., Tobias, A., Tebé, C., Ballana, E., Bassat, Q., Baro, B., Vall-Mayans, M., G-Beiras, C., Prat, N., Ara, J., Clotet, B., & Mitjà, O. (2021). Transmission of COVID-19 in 282 clusters in Catalonia, Spain: a cohort study. The Lancet.Infectious Diseases, 21(5), 629-636. 10.1016/S1473-3099(20)30985-3
  66. McEllistrem, M. C., Clancy, C. J., Buehrle, D. J., Singh, N., Lucas, A., Sirianni, V., & Decker, B. K. (2021). SARS-CoV-2 is associated with high viral loads in asymptomatic and recently symptomatic healthcare workers. PloS One, 16(3), e0248347. 10.1371/journal.pone.0248347
  67. Meiring, S., Tempia, S., Bhiman, J. N., Buys, A., Kleynhans, J., Makhasi, M., McMorrow, M., Moyes, J., Quan, V., Walaza, S., du Plessis, M., Wolter, N., von Gottberg, A., & Cohen, C. (2022). Prolonged Shedding of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at High Viral Loads Among Hospitalized Immunocompromised Persons Living With Human Immunodeficiency Virus (HIV), South Africa. Clinical Infectious Diseases, 75(1), e144-e156. 10.1093/cid/ciac077
  68. Miller, S. L., Nazaroff, W. W., Jimenez, J. L., Boerstra, A., Buonanno, G., Dancer, S. J., Kurnitski, J., Marr, L. C., Morawska, L., & Noakes, C. (2021). Transmission of SARS-CoV-2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event. Indoor Air, 31(2), 314-323. 10.1111/ina.12751
  69. Morawska, L., Johnson, G. R., Ristovski, Z. D., Hargreaves, M., Mengersen, K., Corbett, S., Chao, C. Y. H., Li, Y., & Katoshevski, D. (2009). Size distribution and sites of origin of droplets expelled from the human respiratory tract during expiratory activities. Journal of Aerosol Science, 40(3), 256-269. 10.1016/j.jaerosci.2008.11.002
  70. Moritz, E. D., McKay, S. L., Tobolowsky, F. A., LaVoie, S. P., Waltenburg, M. A., Lecy, K. D., Thornburg, N. J., Harcourt, J. L., Tamin, A., Folster, J. M., Negley, J., Brown, A. C., McDonald, L. C., & Kutty, P. K. (2022). Repeated antigen testing among severe acute respiratory coronavirus virus 2 (SARS-CoV-2)–positive nursing home residents. Infection Control and Hospital Epidemiology, 43(12), 1918-1921. 10.1017/ice.2021.370
  71. Nardell, E. A., & Nathavitharana, R. R. (2020). Airborne Spread of SARS-CoV-2 and a Potential Role for Air Disinfection. Jama, 324(2), 141-142. 10.1001/jama.2020.7603
  72. Nomura, T., Kitagawa, H., Kakimoto, M., Kaiki, Y., Nazmul, T., Miyamori, D., Omori, K., Shigemoto, N., Ito, M., Sakaguchi, T., & Ohge, H. (2022a). Duration of infectious viral shedding in patients with mild to moderate COVID-19 treated with REGN-CoV2. Journal of Infection and Chemotherapy : Official Journal of the Japan Society of Chemotherapy, 28(7), 912-917. 10.1016/j.jiac.2022.03.013
  73. Nomura, T., Kitagawa, H., Omori, K., Shigemoto, N., Kakimoto, M., Nazmul, T., Shime, N., Sakaguchi, T., & Ohge, H. (2022b). Duration of infectious virus shedding in patients with severe coronavirus disease 2019 who required mechanical ventilation. Journal of Infection and Chemotherapy : Official Journal of the Japan Society of Chemotherapy, 28(1), 19-23. 10.1016/j.jiac.2021.09.006
  74. Nussenblatt, V., Roder, A. E., Das, S., de Wit, E., Youn, J., Banakis, S., Mushegian, A., Mederos, C., Wang, W., Chung, M., Pérez-Pérez, L., Palmore, T., Brudno, J. N., Kochenderfer, J. N., & Ghedin, E. (2022). Yearlong COVID-19 Infection Reveals Within-Host Evolution of SARS-CoV-2 in a Patient With B-Cell Depletion. The Journal of Infectious Diseases, 225(7), 1118-1123. 10.1093/infdis/jiab622
  75. O'Kelly, E., Arora, A., Pirog, S., Ward, J., & Clarkson, P. J. (2021). Comparing the fit of N95, KN95, surgical, and cloth face masks and assessing the accuracy of fit checking. PloS One, 16(1), e0245688. 10.1371/journal.pone.0245688
  76. Oksanen, L. A. H., Sanmark, E., Oksanen, S. A., Anttila, V., Paterno, J. J., Lappalainen, M., Lehtonen, L., & Geneid, A. (2021a). Sources of healthcare workers' COVID-19 infections and related safety guidelines. International Journal of Occupational Medicine and Environmental Health, 34(2), 239-249. 10.13075/ijomeh.1896.01741
  77. Oksanen, L. A. H., Sanmark, E., Oksanen, S. A., Anttila, V., Paterno, J. J., Lappalainen, M., Lehtonen, L., & Geneid, A. (2021b). Sources of healthcare workers' COVID-19 infections and related safety guidelines. International Journal of Occupational Medicine and Environmental Health, 34(2), 239-249. 10.13075/ijomeh.1896.01741
  78. O'Neil, C. A., Li, J., Leavey, A., Wang, Y., Hink, M., Wallace, M., Biswas, P., Burnham, C. D., Babcock, H. M., & Centers for Disease Control and Prevention Epicenters Program. (2017). Characterization of Aerosols Generated During Patient Care Activities. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America, 65(8), 1335-1341. 10.1093/cid/cix535
  79. Papineni, R. S., & Rosenthal, F. S. (1997). The size distribution of droplets in the exhaled breath of healthy human subjects. Journal of Aerosol Medicine : The Official Journal of the International Society for Aerosols in Medicine, 10(2), 105-116. 10.1089/jam.1997.10.105
  80. Pei, L., Gao, Z., Yang, Z., Wei, D., Wang, S., Ji, J., & Jiang, B. (2006). Investigation of the influencing factors on severe acute respiratory syndrome among health care workers. Beijing Da Xue Xue Bao.Yi Xue Ban = Journal of Peking University.Health Sciences, 38(3), 271-275.
  81. Pitak-Arnnop, P., Tangmanee, C., Meningaud, J., & Neff, A. (2022). Prolonged viral shedding identified from external splints and intranasal packings in immediately cured COVID-19 patients with nasal fractures: A retrospective study. Journal of Stomatology, Oral and Maxillofacial Surgery, 123(3), 287-291. 10.1016/j.jormas.2022.04.003
  82. Randall, K., Ewing, E. T., Marr, L. C., Jimenez, J. L., & Bourouiba, L. (2021). How did we get here: what are droplets and aerosols and how far do they go? A historical perspective on the transmission of respiratory infectious diseases. Interface Focus, 11(6), 20210049. 10.1098/rsfs.2021.0049
  83. Sajgalik, P., Garzona-Navas, A., Csécs, I., Askew, J. W., Lopez-Jimenez, F., Niven, A. S., Johnson, B. D., & Allison, T. G. (2021). Characterization of Aerosol Generation During Various Intensities of Exercise. Chest, 160(4), 1377-1387. 10.1016/j.chest.2021.04.041
  84. Schijven, J., Vermeulen, L. C., Swart, A., Meijer, A., Duizer, E., & de Roda Husman, A. M. (2021). Quantitative Microbial Risk Assessment for Airborne Transmission of SARS-CoV-2 via Breathing, Speaking, Singing, Coughing, and Sneezing. Environmental Health Perspectives, 129(4), 47002. 10.1289/EHP7886
  85. Shah, A., Wood, R., Gribben, C., Caldwell, D., Bishop, J., Weir, A., Kennedy, S., Reid, M., Smith-Palmer, A., Goldberg, D., McMenamin, J., Fischbacher, C., Robertson, C., Hutchinson, S., McKeigue, P., Colhoun, H., & McAllister, D. (2020). Risk of hospital admission with coronavirus disease 2019 in healthcare workers and their households: nationwide linkage cohort study. Bmj, 371, m3582. 10.1136/bmj.m3582
  86. Sheward, D. J., Kim, C., Ehling, R. A., Pankow, A., Castro Dopico, X., Dyrdak, R., Martin, D. P., Reddy, S. T., Dillner, J., Karlsson Hedestam, G. B., Albert, J., & Murrell, B. (2022). Neutralisation sensitivity of the SARS-CoV-2 omicron (B.1.1.529) variant: a cross-sectional study. The Lancet.Infectious Diseases, 22(6), 813-820. 10.1016/S1473-3099(22)00129-3
  87. Sickbert-Bennett, E. E., Samet, J. M., Clapp, P. W., Chen, H., Berntsen, J., Zeman, K. L., Tong, H., Weber, D. J., & Bennett, W. D. (2020). Filtration Efficiency of Hospital Face Mask Alternatives Available for Use During the COVID-19 Pandemic. JAMA Internal Medicine, 180(12), 1607-1612. 10.1001/jamainternmed.2020.4221
  88. Stadnytskyi, V., Anfinrud, P., & Bax, A. (2021). Breathing, speaking, coughing or sneezing: What drives transmission of SARS-CoV-2? Journal of Internal Medicine, 290(5), 1010-1027. 10.1111/joim.13326
  89. Stadnytskyi, V., Bax, C. E., Bax, A., & Anfinrud, P. (2020). The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission. Proceedings of the National Academy of Sciences of the United States of America, 117(22), 11875-11877. 10.1073/pnas.2006874117
  90. Stockwell, R. E., Ballard, E. L., O'Rourke, P., Knibbs, L. D., Morawska, L., & Bell, S. C. (2019). Indoor hospital air and the impact of ventilation on bioaerosols: a systematic review. The Journal of Hospital Infection, 103(2), 175-184. 10.1016/j.jhin.2019.06.016
  91. Tang, J. W., Marr, L. C., Li, Y., & Dancer, S. J. (2021). Covid-19 has redefined airborne transmission. BMJ (Clinical Research Ed.), 373, n913. 10.1136/bmj.n913
  92. Teleman, M. D., Boudville, I. C., Heng, B. H., Zhu, D., & Leo, Y. S. (2004). Factors associated with transmission of severe acute respiratory syndrome among health-care workers in Singapore. Epidemiology and Infection, 132(5), 797-803. 10.1017/s0950268804002766
  93. Thornton, C. S., Huntley, K., Berenger, B. M., Bristow, M., Evans, D. H., Fonseca, K., Franko, A., Gillrie, M. R., Lin, Y., Povitz, M., Shafey, M., Conly, J. M., & Tremblay, A. (2022). Prolonged SARS-CoV-2 infection following rituximab treatment: clinical course and response to therapeutic interventions correlated with quantitative viral cultures and cycle threshold values. Springer Science and Business Media LLC. 10.1186/s13756-022-01067-1
  94. Tran, K., Cimon, K., Severn, M., Pessoa-Silva, C. L., & Conly, J. (2012). Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review. PloS One, 7(4), e35797. 10.1371/journal.pone.0035797
  95. Trannel, A. M., Kobayashi, T., Dains, A., Abosi, O. J., Jenn, K. E., Meacham, H., Sheeler, L. L., Etienne, W., Kukla, M. E., Alsuhaibani, M., Holley, S., Strandberg, K., Marra, A. R., Kritzman, J., Ford, B., Wellington, M., Diekema, D. J., & Salinas, J. L. (2022). Coronavirus disease 2019 (COVID-19) incidence after exposures in shared patient rooms in a tertiary-care center in Iowa, July 2020-May 2021. Infection Control and Hospital Epidemiology, 43(12), 1910-1913. 10.1017/ice.2021.313
  96. Villaseñor-Echavarri, R., Gomez-Romero, L., Martin-Onraet, A., Herrera, L. A., Escobar-Arrazola, M. A., Ramirez-Vega, O. A., Barrientos-Flores, C., Mendoza-Vargas, A., Hidalgo-Miranda, A., Vilar-Compte, D., & Cedro-Tanda, A. (2023). SARS-CoV-2 Genome Variations in Viral Shedding of an Immunocompromised Patient with Non-Hodgkin's Lymphoma. MDPI AG. 10.3390/v15020377
  97. Wilson, N. M., Marks, G. B., Eckhardt, A., Clarke, A. M., Young, F. P., Garden, F. L., Stewart, W., Cook, T. M., & Tovey, E. R. (2021). The effect of respiratory activity, non-invasive respiratory support and facemasks on aerosol generation and its relevance to COVID-19. Anaesthesia, 76(11), 1465-1474. 10.1111/anae.15475
  98. World Health Organization. (2023a). COVID-19 Epidemiological Update - 24 November 2023. https://www.who.int/publications/m/item/covid-19-epidemiological-update---24-november-2023
  99. World Health Organization. (2023b). Infection prevention and control in the context of COVID-19: a guideline, 21 December 2023. https://www.who.int/publications/i/item/WHO-2019-nCoV-IPC-guideline-2023.4
  100. 100. Yang, L., Zhong, J., Wang, W., Zhou, F., Tong, Z., Zheng, Y., & Chen, X. (2023). Yang et al., 202310.5144/0256-
  101. Yin Mo, David W. Eyre, Sheila F. Lumley, Timothy M. Walker, Robert H. Shaw, Denise O'Donnell, Lisa Butcher, Katie Jeffery, Christl A. Donnelly, Oxford COVID infection review team, & Ben S. Cooper. (2021). Transmission dynamics of SARS-CoV-2 in the hospital setting. medRxiv, , 2021.04.28.21256245. 10.1101/2021.04.28.21256245
  102. Yin, Y., Zeng, T., Lai, M., Luan, Z., Wang, K., Ma, Y., Hu, Z., Wang, K., & Peng, Z. (2023). Impact of antibody-level on viral shedding in B.1.617.2 (Delta) variant-infected patients analyzed using a joint model of longitudinal and time-to-event data. American Institute of Mathematical Sciences (AIMS). 10.3934/mbe.2023390
  103. Zhang, X., Zhang, L., Zhang, K., Chen, Y., & Wang, L. (2023). Immunocompromised states caused the prolonged duration of viral shedding in middle‐aged and elderly hemodialysis patients infected with the Omicron variant of COVID‐19. Therapeutic Apheresis and Dialysis, 27(4), 720-725. 10.1111/1744-9987.13969
  104. Zhong, W., Yang, X., Jiang, X., Duan, Z., Wang, W., Sun, Z., Chen, W., Zhang, W., Xu, J., Cheng, J., Yuan, X., & Li, Y. (2023). Factors associated with prolonged viral shedding in older patients infected with Omicron BA.
  105. Zhou, X., Huang, X., Sun, T., Jin, X., Tian, Z., Xue, M., Kang, J., Gao, B., Xu, A., Chen, Y., Jia, Y., & Liu, S. (2023). Chronological changes of viral shedding in adult inpatients with Omicron infection in Shanghai, China. Frontiers in Immunology, 14, 1090498. 10.3389/fimmu.2023.1090498

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