Evaluation of real and perceived risk to health care workers caring for patients with the Omicron variant of the SARS-CoV-2 virus in surgery and obstetrics

IntroductionThe Omicron variant of the SARS-CoV-2 virus is described as more contagious than previous variants. We sought to assess risk to healthcare workers (HCWs) caring for patients with COVID-19 in surgical/obstetrical settings, and the perception of risk amongst this group. MethodsFrom January to April, 2022, reverse transcription polymerase chain reaction was used to detect the presence of SARS-CoV-2 viral RNA in patient, environmental (floor, equipment, passive air) samples, and HCWs masks (inside surface) during urgent surgery or obstetrical delivery for patients with SARS-CoV-2 infection. The primary outcome was the proportion of HCWs masks testing positive. Results were compared with our previous cross-sectional study involving obstetrical/surgical patients with earlier variants (2020/21). HCWs completed a risk perception electronic questionnaire. Results11 patients were included: 3 vaginal births and 8 surgeries. 5/108 samples (5%) tested positive (SARS-CoV-2 Omicron) viral RNA: 2/5 endotracheal tubes, 1/22 floor samples, 1/4 patient masks and 1 nasal probe. No samples from the HCWs masks (0/35), surgical equipment (0/10) and air samples (0/11) tested positive. No significant differences were found between the Omicron and 2020/21 patient groups positivity rates (Mann-Whitney U test, p = 0.838) or the level of viral load from the nasopharyngeal swabs (p = 0.405). Nurses had a higher risk perception than physicians (p = 0.038). ConclusionNo significant difference in contamination rates were found between SARS-CoV-2 Omicron BA.1 and previous variants in surgical/obstetrical settings. This is reassuring as no HCW mask was positive and no HCW tested positive for COVID-19 post-exposure.

Detection of SARS CoV-2 contamination in the Operating Room and Birthing Room Setting: Risks to attending health care workers

BackgroundThe exposure risks to front-line health care workers who are in close proximity for prolonged periods of time, caring for COVID-19 patients undergoing surgery or obstetrical delivery is unclear. Understanding of sample types that may harbour virus is important for evaluating risk. ObjectivesTo determine if SARS-CoV-2 viral RNA from patients with COVID-19 undergoing surgery or obstetrical care is present in: 1) the peritoneal cavity of males and females 2) the female reproductive tract, 3) the environment of the surgery or delivery suite (surgical instruments, equipment used, air or floors) and 4) inside the masks of the attending health care workers. MethodsThe presence of SARS-CoV-2 viral RNA in patient, environmental and air samples was identified by real time reverse transcriptase polymerase chain reaction (RT-PCR). Air samples were collected using both active and passive sampling techniques. ResultsIn this multi-centre observational case series, 32 patients with COVID-19 underwent urgent surgery or obstetrical delivery and 332 patient and environmental samples were collected and analyzed to determine if SARS-CoV-2 RNA was present. SARS-CoV-2 RNA was detected in: 4/24(16.7%) patient samples, 5/60(8.3%) floor, 1/54(1.9%) air, 10/23(43.5%) surgical instruments/equipment, 0/24 cautery filters and 0/143 inner surface of mask samples. ConclusionsWhile there is evidence of SARS-CoV-2 RNA in the surgical and obstetrical operative environment (6% of samples taken), the finding of no detectable virus inside the masks worn by the medical teams would suggest a low risk of infection for our health care workers using appropriate personal protective equipment (PPE).

Surface and air contamination with SARS-CoV-2 from hospitalized COVID-19 patients in Toronto, Canada

BackgroundThe aim of this prospective cohort study was to determine the burden of SARS-CoV-2 in air and on surfaces in rooms of patients hospitalized with COVID-19, and to identify patient characteristics associated with SARS-CoV-2 environmental contamination. MethodsNasopharyngeal swabs, surface, and air samples were collected from the rooms of 78 inpatients with COVID-19 at six acute care hospitals in Toronto from March to May 2020. Samples were tested for SARS-CoV-2 viral RNA and cultured to determine potential infectivity. Whole viral genomes were sequenced from nasopharyngeal and surface samples. Association between patient factors and detection of SARS-CoV-2 RNA in surface samples were investigated using a mixed-effects logistic regression model. FindingsSARS-CoV-2 RNA was detected from surfaces (125/474 samples; 42/78 patients) and air (3/146 samples; 3/45 patients) in COVID-19 patient rooms; 17% (6/36) of surface samples from three patients yielded viable virus. Viral sequences from nasopharyngeal and surface samples clustered by patient. Multivariable analysis indicated hypoxia at admission, a PCR-positive nasopharyngeal swab with a cycle threshold of [≤]30 on or after surface sampling date, higher Charlson co-morbidity score, and shorter time from onset of illness to sample date were significantly associated with detection of SARS-CoV-2 RNA in surface samples. InterpretationThe infrequent recovery of infectious SARS-CoV-2 virus from the environment suggests that the risk to healthcare workers from air and near-patient surfaces in acute care hospital wards is likely limited. Surface contamination was greater when patients were earlier in their course of illness and in those with hypoxia, multiple co-morbidities, and higher SARS-CoV-2 RNA concentration in NP swabs. Our results suggest that air and surfaces may pose limited risk a few days after admission to acute care hospitals.