[Detection and evaluation of SARS CoV 2 nucleic acid contamination in corona virus disease 19 ward surroundings and the surface of medical staff's protective equipment]
OBJECTIVE To determine the environmental contamination degree of severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) in corona virus disease 2019 (COVID 19) wards, to offer gui dance for the infection control and to improve safety practices for medical staff, by sampling and detecting SARS CoV 2 nucleic acid from the air of hospital wards, the high frequency contact surfaces in the contaminated area and the surfaces of medical staff's protective equipment in a COVID 19 designated hospital in Wuhan, China. METHODS From March 11 to March 19, 2020, we collected air samples from the clean area, the buffer room and the contaminated area respectively in the COVID 19 wards using a portable bioaerosol concentrator WA 15. And sterile premoistened swabs were used to sample the high frequency contacted surfaces in the contaminated area and the surfaces of medical staff's protective equipment including outermost gloves, tracheotomy operator's positive pressure respiratory protective hood and isolation clothing. The SARS CoV 2 nucleic acid of the samples were detected by real time fluorescence quantitative PCR. During the isolation medical observation period, those medical staff who worked in the COVID 19 wards were detected for SARS CoV 2 nucleic acid with oropharyngeal swabs, IgM and IgG antibody in the sera, and chest CT scans to confirm the infection status of COVID 19. RESULTS No SARS CoV 2 nucleic acid was detected in the tested samples, including the 90 air samples from the COVID 19 wards including clean area, buffer room and contaminated area, the 38 high frequency contact surfaces samples of the contaminated area and 16 surface samples of medical staff's protective equipment including outermost gloves and isolation clothing. Moreover, detection of SARS CoV 2 nucleic acid by oropharyngeal swabs and IgM, IgG antibodies in the sera of all the health care workers who participated in the treatment for COVID 19 were all negative. Besides, no chest CT scan images of medical staff exhibited COVID 19 lung presentations. CONCLUSION Good ventilation conditions, strict disinfection of environmental facilities in hospital wards, guidance for correct habits in patients, and strict hand hygiene during medical staff are important to reduce the formation of viral aerosols, cut down the aerosol load, and avoid cross infection in isolation wards. In the face of infectious diseases that were not fully mastered but ma naged as class A, it is safe for medical personnel to be equipped at a high level.
Beijing da xue xue bao. Yi xue ban Journal of Peking University. Health sciences