key: cord-1020631-mkpd5wva authors: Ong, Sean Wei Xiang; Tan, Yian Kim; Sutjipto, Stephanie; Chia, Po Ying; Young, Barnaby Edward; Gum, Marcus; Lau, Sok Kiang; Chan, Monica; Vasoo, Shawn; Mendis, Shehara; Toh, Boon Kiat; Leong, Janice; Barkham, Timothy; Ang, Brenda Sze Peng; Tan, Boon Huan; Leo, Yee-Sin; Marimuthu, Kalisvar; Wong, Michelle Su Yen; Ng, Oon Tek title: Absence of contamination of personal protective equipment (PPE) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) date: 2020-03-26 journal: Infection control and hospital epidemiology DOI: 10.1017/ice.2020.91 sha: 13df1c4e393d2c19f9ea08ad9ef9de4a9476948f doc_id: 1020631 cord_uid: mkpd5wva nan Local transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in Singapore has been reported. 1 As the pandemic spreads globally, increased utilization and shortages of personal protective equipment (PPE) are expected. Although extended PPE use would mitigate utilization rate, its safety is unknown. At the National Centre for Infectious Diseases, recommendations for healthcare workers (HCWs) in contact with known or suspected patients are in concordance with the US Centers for Disease Control and Prevention, which recommends gloves, gown, respiratory protection (eg, disposable N95 respirator), and eye protection (eg, goggles or disposable face shield), without the use of shoe covers. 2 An initial pilot study showed no contamination of N95 and disposable face visors after patient care, although in 1 instance, SARS-CoV-2 nucleic acid was detected on the front surface of an HCW's shoe. 3 To evaluate the safety of extended PPE use, we conducted a 1-day PPE sampling study on HCWs caring for confirmed COVID-19 patients to ascertain the per contact episode risk of PPE contamination with SARS-CoV-2. The PPE samples were collected by 5 trained personnel using a standardized technique with Puritan EnviroMax Plus premoistened sterile swabs (Puritan Medical Products, Guilford, ME) from the entire front of goggles, the front surface of N95 respirator, and the front surfaces of shoes of 30 HCWs (Table 1 ) exiting patient rooms. Gloves and gowns were not swabbed because these are disposed after each use. Data on HCW category and details of activity in the room were recorded. Patients with positive SARS-CoV-2 PCR assays within the prior 48 hours were selected, and clinical data (ie, day of illness, presence of symptoms, and cycle threshold [Ct] value of clinical PCR) were obtained from the medical record. Environmental samples were tested using specific real-time RT-PCR methods targeting the SARS-CoV-2 RNAdependent RNA polymerase (RdRP) and E genes. 4 In total, 15 patients (7 women and 8 men) were selected. Patient characteristics varied by day of illness (median, day 14; interquartile range [IQR], 8.25-17.25), presence of symptoms (63% symptomatic), and clinical PCR Ct value (median, 30.08; IQR 28.85-30.86). No patient required ventilatory support and no aerosol-generating procedures were carried out prior to or during sampling. All 90 samples from 30 HCWs (doctors, nurses, and cleaners) were negative ( Table 1 ). The median time spent in the patient's room overall was 6 minutes (IQR, 5-10): 8 minutes for doctors, 7 minutes for nurses, and 3 minutes for cleaning staff. Activities ranged from casual contact (eg, administering medications or cleaning) to closer contact (eg, physical examination or collection of respiratory samples). Our study had several limitations. One limitation of our study was the use of surface swabs for sampling the surface of N95 masks rather than processing masks in extraction buffers with detergents, which is a method that has been used for isolation of influenza from N95 respirators. 5 Surface swabbing may be insufficient for the detection of entrapped viral particles. Second, all patients were in airborne infection isolation rooms with 12 air exchanges per hour, and these results may not be generalizable to other room configurations. Third, we did not assess the concomitant level of viral contamination of the environment in this study to correlate with the level of PPE contamination. Previous laboratory studies have demonstrated that viruses, such as SARS-CoV and human coronavirus 229E, can remain viable on PPE items, including latex gloves and disposable gowns, 6-8 but these studies 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. These results provide assurance that extended use of N95 and goggles with strict adherence to environmental and hand hygiene while managing SARS-CoV-2 patients could be a safe option. Note. Ct, cycle threshold. Cycle threshold refers to the number of cycles required for the fluorescent signal to cross the threshold in RT-PCR; a lower cycle threshold value indicates a higher viral load. Epidemiologic features and clinical course of patients infected with SARS-CoV-2 in Singapore Interim infection prevention and control recommendations for patients with known or patients under investigation for 2019 novel coronavirus (2019-nCoV) in a healthcare setting Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR Assessment of influenza virus exposure and recovery from contaminated surgical masks and N95 respirators Survival of severe acute respiratory syndrome coronavirus Survival of human coronaviruses 229E and OC43 in suspension and after drying onsurfaces: a possible source ofhospitalacquired infections Coronavirus survival on healthcare personal protective equipment Acknowledgments. We thank Ding Ying and other members of the All authors report no conflicts of interest relevant to this article.