#15,272
Late last week, in DHS: Decay Rate Calculator For SARS-CoV-2, we looked at tool to calculate the potential persistence of the SARS-CoV-2 virus on environmental surfaces based on temperature and humidity.
The `right' temperature and humidity levels can increase the viability of the virus by days. Lower temperatures, and lower humidities - such as you often find in a hospital or office environment - are particularly helpful in extending the life of the virus.With that in mind, we've a new Dispatch published in the CDC's EID Journal that looks at the rapid (< 24 hrs) environmental contamination of surfaces in hotel rooms which were occupied by two presymptomatic students placed under quarantine.
I've only included some excerpts from the dispatch, so follow the link to read it in its entirety. I'll have a postscript when you return.
Volume 26, Number 9—September 2020
Dispatch
Detection of Severe Acute Respiratory Syndrome Coronavirus 2 RNA on Surfaces in Quarantine Rooms
Fa-Chun Jiang1, Xiao-Lin Jiang1, Zhao-Guo Wang, Zhao-Hai Meng, Shou-Feng Shao, Benjamin D. Anderson, and Mai-Juan Ma
Abstract
We investigated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) environmental contamination in 2 rooms of a quarantine hotel after 2 presymptomatic persons who stayed there were laboratory-confirmed as having coronavirus disease. We detected SARS-CoV-2 RNA on 8 (36%) of 22 surfaces, as well as on the pillow cover, sheet, and duvet cover.
(SNIP)
The Study
Two Chinese students studying overseas returned to China on March 19 (patient A) and March 20 (patient B), 2020 (Table 1). On the day of their arrival in China, neither had fever or clinical symptoms, and they were transferred to a hotel for a 14-day quarantine. They had normal body temperatures (patient A, 36.3°C; patient B, 36.5°C) and no symptoms when they checked into the hotel. During the quarantine period, local medical staff were to monitor their body temperature and symptoms each morning and afternoon. On the morning of the second day of quarantine, they had no fever (patient A, 36.2°C for patient A; patient B, 36.7°C) or symptoms.
At the same time their temperatures were taken, throat swab samples were collected; both tested positive for SARS-CoV-2 RNA by real-time reverse transcription PCR (rRT-PCR).
The students were transferred to a local hospital for treatment. At admission, they remained presymptomatic, but nasopharyngeal swab, sputum, and fecal samples were positive for SARS-CoV-2 RNA with high viral loads (Table 1). In patient A, fever (37.5°C) and cough developed on day 2 of hospitalization, but his chest computed tomography images showed no significant abnormality during hospitalization. In patient B, fever (37.9°C) and cough developed on day 6 of hospitalization, and her computed tomography images showed ground-glass opacities.
Approximately 3 hours after the 2 patients were identified as positive for SARS-CoV-2 RNA, we sampled the environmental surfaces of the 2 rooms in the centralized quarantine hotel in which they had stayed.
(SNIP)
Conclusions
Our study demonstrates extensive environmental contamination of SARS-CoV-2 RNA in a relatively short time (< 24 hours) in occupied rooms of 2 persons who were presymptomatic. We also detected SARS-CoV-2 RNA in the surface swab samples of the pillow cover, duvet cover, and sheet.
Evidence for SARS-CoV-2 transmission by indirect contact was identified in a cluster of infections at a shopping mall in China (10). However, no clear evidence of infection caused by contact with the contaminated environment was found. SARS-CoV-2 RNA has been detected on environmental surfaces in isolation rooms where the symptomatic or paucisymptomatic patients stayed for several days (3–5).
In our study, we demonstrate high viral load shedding in presymptomatic patients, which is consistent with previous studies (8,9), providing further evidence for the presymptomatic transmission of the virus (5,11–15). In addition, presymptomatic patients with high viral load shedding can easily contaminate the environment in a short period.
Our results also indicate a higher viral load detected after prolonged contact with sheets and pillow covers than with intermittent contact with the door handle and light switch. The detection of SARS-CoV-2 RNA in the surface samples of the sheet, duvet cover, and pillow cover highlights the importance of proper handling procedures when changing or laundering used linens of SARS-CoV-2 patients. Thus, to minimize the possibility of dispersing virus through the air, we recommend that used linens not be shaken upon removal and that laundered items be thoroughly cleaned and dried to prevent additional spread.
The absence of viral isolation in our investigation was an obstacle to demonstrating the infectivity of the virus, but SARS-CoV-2 has been reported to remain viable on surfaces of plastic and stainless steel for up to 4–7 days (6,7) and 1 day for treated cloth (7).
In summary, our study demonstrates that presymptomatic patients have high viral load shedding and can easily contaminate environments. Our data also reaffirm the potential role of surface contamination in the transmission of SARS-CoV-2 and the importance of strict surface hygiene practices, including regarding linens of SARS-CoV-2 patients.
Dr. Jiang is an epidemiologist in Qingdao Center for Disease Control and Prevention, Qingdao, Shandong Province, China. His primary research interests included infectious disease control and prevention and emerging infectious diseases.
Nearly all of the guidance we've seen on the environmental persistence of SARS-CoV-2 has focused on aerosols and hard surfaces like plastic, stainless steel, copper, and cardboard (see Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1).
Data on fabrics, clothing, and other porous materials appears to be lacking, although the CDC does offer this advice for laundering items from a `sick room'.The guidance being offered to hotels and motels on cleaning and disinfecting rooms appears to vary widely by state. While bed linens are routinely changed and laundered daily, in most hotels bedspreads, blankets, and duvet covers are laundered only a few times each year.
California's Hotel Guidance, which provides one of the most detailed plans I've seen, suggests:
- Dirty linens should be removed and transported from guest rooms in single-use, sealed bags and pillow protectors on the guest room beds should be changed daily. Bagging of these items should be done in the guest room to eliminate excess contact while being transported. All bed linen and laundry should be washed at a high temperature and cleaned in accordance with CDC guidelines.
- Consider leaving rooms vacant for 24 to 72 hours prior to or after cleaning.
Meanwhile, West Virginia's COVID-19 Guidance for Hotels simply says:
- Linens may become contaminated with the virus, so it is also important to add disinfectant when washing laundry. Bed scarfs and bedspreads should be washed more frequently
