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Swabbed PPE worn during COVID-19 patient care test negative for virus

Personal protective equipment, including goggles, N95 respirators and shoes, worn by health care workers caring for patients with SARS-CoV-2 tested negative for the virus, according to a recent study.

“As the pandemic [of SARS-CoV-2] spreads globally, increased utilization and shortages of personal protective equipment (PPE) are expected. While extended PPE use would mitigate utilization rate, its safety is unknown,” Sean Wei Xiang Ong, MBBS, of the National Centre for Infectious Diseases in Singapore and the Department of Infectious Diseases at Tan Tock Seng Hospital, also in Singapore, and colleagues wrote. “To evaluate the safety of extended PPE use, we conducted a 1-day PPE sampling study on health care workers caring for confirmed SARS-CoV-2-infected patients to ascertain the per contact episode risk of PPE contamination with SARS-CoV-2.”

Ong and colleagues collected the samples from PPE using a standardized technique with Puritan EnviroMax Plus premoistened sterile swabs from the entire front of goggles, front surface of N95 respirators and the front surface of shoes from health care workers leaving the rooms of patients. Gloves and gowns were not swabbed because these items are disposed of after each use. Patients were chosen based on a positive SARS-CoV-2 PCR test result within the previous 48 hours.

In total, 90 samples were collected from 30 health care workers, including doctors, nurses and cleaners, leaving the rooms of 15 patients. According to the study results, median time spent in the patient’s room was 6 minutes. Activities performed in the room ranged from casual contact such as administering medications and cleaning to closer contact like a physical examination and the collection of respiratory samples. Results showed that all 90 of the samples obtained from health care workers tested negative for SARS-CoV-2.

The authors noted that the study did have several limitations, including the use of surface swabs for sampling N95 masks, rather than processing masks in extraction buffers with detergents a method used for isolation of influenza from N95 respirators. According to Gordon and colleagues, this method “may be insufficient for detection of entrapped viral particles.” All patients were being treated in airborne infection isolation rooms with 12 air exchanges per hour, which could mean that the results are not generalizable to other types of rooms. The authors also did not evaluate the concomitant level of viral contamination in the environment to correlate with the degree of PPE contamination.

“Previous laboratory studies demonstrated that viruses such as SARS-CoV and human coronavirus 229E can remain viable on PPE items, including latex gloves and disposable gowns, though these were not performed in clinical settings. Despite the potential for extensive environmental contamination by SARS-CoV-2, we did not find similar contamination of PPE after patient contact,” the authors concluded. “This provides assurance that extended use of N95 [respirators] and goggles with strict adherence to environmental and hand hygiene while managing [patients with] SARS-CoV-2 could be a safe option.” – by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.