SARS-CoV-2 Aerosol and Surface Detections in COVID-19 Testing Centers and Implications for Transmission Risk in Public Facing Workers.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and resulting COVID-19 (coronavirus disease 2019) pandemic have required mass diagnostic testing, often taking place in testing sites within hospitals, clinics, or at satellite locations. To establish the potential of SARS-CoV-2 aerosol transmission and to identify junctures during testing that result in increased viral exposure, aerosol and surface samples were examined for the presence of SARS-CoV-2 RNA from locations within Nebraska Medicine COVID-19 testing and vaccine clinics. Aerosols containing SARS-CoV-2 RNA detected within clinics suggest viral shedding from infected individuals. SARS-CoV-2 RNA detection in aerosol samples was shown to correlate with clinic operation and patient infection, as well as with community infection findings. Additionally, SARS-CoV-2 RNA was detected in surface samples collected from clinics. The presence of SARS-CoV-2 RNA in aerosols in these clinics supports the continued use of respiratory protection and sanitization practices for healthcare workers, and other workers with public facing occupations.

Infectious Aerosol Capture Mask as Environmental Control to Reduce Spread of Respiratory Viral Particles.

Negative pressure isolation of COVID-19 patients is critical to limiting the nosocomial transmission of SARS-CoV-2; however, airborne isolation rooms are limited. Alternatives to traditional isolation procedures are needed. The evaluation of an Infectious Aerosol Capture Mask (IACM) that is designed to augment the respiratory isolation of COVID-19 patients is described. Efficacy in capturing exhaled breath aerosols was evaluated using laboratory experimentation, computational fluid dynamics (CFD) and measurements of exhaled breath from COVID-19 patients and their surroundings. Laboratory aerosol experiments indicated that the mask captured at least 99% of particles. Simulations of breathing and speaking showed that all particles between 0.1 and 20 µm were captured either on the surface of the mask or in the filter. During coughing, no more than 13% of the smallest particles escaped the mask, while the remaining particles collected on the surfaces or filter. The total exhaled virus concentrations of COVID-positive patients showed a range from undetectable to 1.1 × 106 RNA copies/h of SARS-CoV-2, and no SARS-CoV-2 aerosol was detected in the samples collected that were adjacent to the patient when the mask was being worn. These data indicate that the IACM is useful for containing the exhaled aerosol of infected individuals and can be used to quantify the viral aerosol production rates during respiratory activities.

Aerosol tracer testing in Boeing 767 and 777 aircraft to simulate exposure potential of infectious aerosol such as SARS-CoV-2.

The COVID-19 pandemic has reintroduced questions regarding the potential risk of SARS-CoV-2 exposure amongst passengers on an aircraft. Quantifying risk with computational fluid dynamics models or contact tracing methods alone is challenging, as experimental results for inflight biological aerosols is lacking. Using fluorescent aerosol tracers and real time optical sensors, coupled with DNA-tagged tracers for aerosol deposition, we executed ground and inflight testing on Boeing 767 and 777 airframes. Analysis here represents tracer particles released from a simulated infected passenger, in multiple rows and seats, to determine the exposure risk via penetration into breathing zones in that row and numerous rows ahead and behind the index case. We present here conclusions from 118 releases of fluorescent tracer particles, with 40+ Instantaneous Biological Analyzer and Collector sensors placed in passenger breathing zones for real-time measurement of simulated virus particle penetration. Results from both airframes showed a minimum reduction of 99.54% of 1 µm aerosols from the index source to the breathing zone of a typical passenger seated directly next to the source. An average 99.97 to 99.98% reduction was measured for the breathing zones tested in the 767 and 777, respectively. Contamination of surfaces from aerosol sources was minimal, and DNA-tagged 3 µm tracer aerosol collection techniques agreed with fluorescent methodologies.

Author Correction: Aerosol and surface contamination of SARS-CoV-2 observed in quarantine and isolation care.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The size and culturability of patient-generated SARS-CoV-2 aerosol.

BACKGROUND: Aerosol transmission of COVID-19 is the subject of ongoing policy debate. Characterizing aerosol produced by people with COVID-19 is critical to understanding the role of aerosols in transmission. OBJECTIVE: We investigated the presence of virus in size-fractioned aerosols from six COVID-19 patients admitted into mixed acuity wards in April of 2020. METHODS: Size-fractionated aerosol samples and aerosol size distributions were collected from COVID-19 positive patients. Aerosol samples were analyzed for viral RNA, positive samples were cultured in Vero E6 cells. Serial RT-PCR of cells indicated samples where viral replication was likely occurring. Viral presence was also investigated by western blot and transmission electron microscopy (TEM). RESULTS: SARS-CoV-2 RNA was detected by rRT-PCR in all samples. Three samples confidently indicated the presence of viral replication, all of which were from collected sub-micron aerosol. Western blot indicated the presence of viral proteins in all but one of these samples, and intact virions were observed by TEM in one sample. SIGNIFICANCE: Observations of viral replication in the culture of submicron aerosol samples provides additional evidence that airborne transmission of COVID-19 is possible. These results support the use of efficient respiratory protection in both healthcare and by the public to limit transmission.

Implementation of a COVID-19 cohort area resulted in no surface or air contamination in surrounding areas in one academic emergency department.

INTRODUCTION: As a result of the COVID-19 pandemic and highly contagious nature of SARS-CoV-2, emergency departments (EDs) have been forced to implement new measures and protocols to minimize the spread of the disease within their departments. The primary objective of this study was to determine if the implementation of a designated COVID-19 cohort area (hot zone) within a busy ED mitigated the dissemination of SARS-CoV-2 throughout the rest of the department. METHODS: In an ED of a tertiary academic medical center, with 64,000 annual visits, an eight room pod was designated for known COVID-19 or individuals with high suspicion for infection. There was a single entry and exit for donning and doffing personal protective equipment (PPE). Health care workers (HCW) changed gowns and gloves between patients, but maintained their N-95 mask and face shield, cleaning the shield with a germicidal wipe between patients. Staffing assignments designated nurses and technicians to remain in this area for 4 h, where physicians regularly moved between the hot zone and rest of the ED. Fifteen surface samples and four air samples were taken to evaluate SARS-CoV-2 contamination levels and the effectiveness of infection control practices. Samples were collected outside of patient rooms in 3 primary ED patient care areas, the reception area, the primary nurses station, inside the cohort area, and the PPE donning and doffing areas immediately adjacent. Samples were recovered and analyzed for the presence of the E gene of SARS-CoV-2 using RT-PCR. RESULTS: SARS-CoV-2 was not detected on any surface samples, including in and around the cohort area. All air samples outside the COVID-19 hot zone were negative for SARS-CoV-2, but air samples within the cohort area had a low level of viral contamination. CONCLUSION: A designated COVID-19 cohort area resulted in no air or surface contamination outside of the hot zone, and only minimal air, but no surface contamination, within the hot zone.

Aerosol and surface contamination of SARS-CoV-2 observed in quarantine and isolation care.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originated in Wuhan, China in late 2019, and its resulting coronavirus disease, COVID-19, was declared a pandemic by the World Health Organization on March 11, 2020. The rapid global spread of COVID-19 represents perhaps the most significant public health emergency in a century. As the pandemic progressed, a continued paucity of evidence on routes of SARS-CoV-2 transmission has resulted in shifting infection prevention and control guidelines between classically-defined airborne and droplet precautions. During the initial isolation of 13 individuals with COVID-19 at the University of Nebraska Medical Center, we collected air and surface samples to examine viral shedding from isolated individuals. We detected viral contamination among all samples, supporting the use of airborne isolation precautions when caring for COVID-19 patients.