key: cord-0897191-40ojqv1y
authors: Ben-Shmuel, Amir; Brosh-Nissimov, Tal; Glinert, Itai; Bar-David, Elad; Sittner, Assa; Poni, Reut; Cohen, Regev; Achdout, Hagit; Tamir, Hadas; Yahalom-Ronen, Yfat; Politi, Boaz; Melamed, Sharon; Vitner, Einat; Cherry, Lilach; Israeli, Ofir; Beth-Din, Adi; Paran, Nir; Israely, Tomer; Yitzhaki, Shmuel; Haim levy; Weiss, Shay
title: Detection and infectivity potential of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) environmental contamination in isolation units and quarantine facilities
date: 2020-09-10
journal: Clin Microbiol Infect
DOI: 10.1016/j.cmi.2020.09.004
sha: c72ea8846db0028599a07e8eefd087ede77f6dad
doc_id: 897191
cord_uid: 40ojqv1y

OBJECTIVES: Environmental surfaces have been suggested as likely contributors to the transmission of COVID-19. This study assessed the infectivity of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) contamination on surfaces and objects in hospital isolation units and a quarantine hotel. METHODS: SARS-CoV-2 virus stability and infectivity on non-porous surfaces was tested under controlled laboratory conditions. Surfaces and air sampling was conducted at two COVID-19 isolation units and in a quarantine hotel. Viral RNA detected by RT-PCR and infectivity was assessed by VERO E6 CPE test. RESULTS: In laboratory-controlled conditions, SARS-CoV-2 gradually lost its infectivity completely at day 4 at ambient temperature and the decay rate of viral viability on surfaces directly correlated with increase in temperature. Viral RNA detected in 29/55 (52.7%) and 16/42 (38%) surface samples from the surrounding of symptomatic COVID-19 patients in isolation units of two hospitals and in a quarantine hotel for asymptomatic and very mild COVID-19 patients. None of the surface and air samples from all three sites (0/97) were found to contain infectious titers SARS-Cov-2 in tissue culture assay. CONCLUSIONS: Despite prolonged viability of SARS-CoV-2 in laboratory-controlled conditions, uncultivable viral contamination on inanimate surfaces might suggest low feasibility for indirect fomite transmission.

Sampling was performed in COVID-19 isolation units in two hospitals and one quarantine 78 facility. Hospital-A isolation unit is a 28-bed ward, comprised of secluded rooms occupied by 1- unit is a 40-bed ward, comprised of secluded rooms occupied by 1-6 patients each. Staff used 84 coveralls, masks, shoe covers and face shields. SOP was the use of two pairs of gloves at a time.

The outer pair was not consistently changed during patient care. At the time of sampling, the unit 86 contained patients with mild-to-severe disease, including seven ventilated patients. In both 87 hospitals, patients were free to ambulate in the unit if they were fit to walk. In addition, routine 88 cleaning and decontamination was done twice a day using 1000ppm bleach solution in both 89 wards. The quarantine facility was a hotel repurposed for the isolation of patients with 90 asymptomatic to mild disease until becoming negative for viral nasopharyngeal PCR. Sampling 91 J o u r n a l P r e -p r o o f was conducted at main public areas and in hotel rooms. Patients stayed in private rooms either 92 alone or as a family but were free to move around the hotel and socialize in public spaces.

Routine cleaning and decontamination was done once daily at best only on communal areas. was tested by seeding quadruplets of 200 µl on VERO E6 cells for CPE assay as described 115 above. CPE assay limit of detection has been determined to be 10PFU/ml. Finally, we mapped the contamination in a quarantine hotel for asymptomatic (patients found to 155 be infected during contact testing but had no symptoms) and very mild COVID-19 patients.

Sampling was performed at the hotel communal areas and at three hotel rooms that had been 157 J o u r n a l P r e -p r o o f recently (2-4 days) occupied by newly diagnosed patients. We found that 16/42 (38%) samples 158 were positive for viral RNA (Table 2) . At the communal areas we found viral RNA 159 contamination on a water cooler, chairs, most elevator buttons, a kettle and a used cup. 

In this study, viral RNA contamination was found in 46% of the surface and air samples. 

Our study has some limitations. There was a delay between onset of symptoms and the actual 217 sampling in patients' rooms. Therefore, at the time of sampling these patients might not have 218 shed viable virus as suggested by studies that showed culturable viruses in respiratory samples 219 up to 8 th -9 th day of illness (18, 24) . For that reason, we have noted new patients with recent 220 disease onset in hospital A and the quarantine hotel and sampled around them. The CPE assay 221 has a 10pfu/ml limit of detection that is comparable to CT value of 34, therefore a very low level J o u r n a l P r e -p r o o f

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