SARS-CoV-2 in hospital indoor environments is predominantly non-infectious

Abstract

Background The ongoing SARS-CoV-2 pandemic has spread rapidly worldwide and disease prevention is more important than ever. In the absence of a vaccine, knowledge of the transmission routes and risk areas of infection remain the most important existing tools to prevent further spread. Methods Here we investigated the presence of the SARS-CoV-2 virus in the hospital environment at the Uppsala University Hospital Infectious Disease ward by RT-qPCR and determined the infectivity of the detected virus in vitro on Vero E6 cells. Results SARS-CoV-2 RNA was detected in several areas, although attempts to infect Vero E6 cells with positive samples were unsuccessful. However, RNase A treatment of positive samples prior to RNA extraction did not degrade viral RNA, indicating the presence of SARS-CoV-2 nucleocapsids or complete virus particles protecting the RNA as opposed to free viral RNA. Conclusion Our results show that even in places where a moderate concentration (Ct values between 30 and 38) of SARS-CoV-2 RNA was found; no infectious virus could be detected. This suggests that the SARS-CoV-2 virus in the hospital environment subsides in two states; as infectious and as non-infectious. Future work should investigate the reasons for the non-infectivity of SARS-CoV-2 virions.

Detection and isolation of airborne SARS‐CoV‐2 in a hospital setting

“…Inactivation of bacteria or viruses is expected during electrostatic air sampling, 42–44 including on our own THOR collector 27 . Interestingly, a recent air sampling study performed in the same infectious disease unit was unable to retrieve active virus from air using a different electrostatic collector 36 . Our shorter sampling interval and ability to rapidly immerse sample into buffer may have helped preserve viral activity in our material.…”

Elucidating the role of environmental management of forests, air quality, solid waste and wastewater on the dissemination of SARS-CoV-2

“… Di Maria et al (2021) detected SARS -CoV -2 RNA on 15% of 1175 samples of solid waste such as plastic coffee cups, plastic glasses, beverage cans, and plastic bottles that contained saliva with a viral load ranging from 4.8 × 10 3 to 4.0 × 10 6 genome copies/swab. Pertaining to medical waste materials, SARS-CoV-2 RNA has been detected on outer surface of medical waste bags ( Lv et al, 2021 ) , surgical masks ( Hu et al, 2020 ; Pasquarella et al, 2020 ; Dargahi et al, 2021 ), PPE of health care worker ( Peyrony et al, 2020 ), used gloves ( Ye et al, 2020 ), PPE of medical staff including aprons and face shields ( Krambrich et al, 2021 ) and outer part of the N-95 masks ( Dargahi et al, 2021 ). In the above studies, only Hu et al (2020) and Krambrich et al (2021) tested viral infectivity.…”

“…Pertaining to medical waste materials, SARS-CoV-2 RNA has been detected on outer surface of medical waste bags ( Lv et al, 2021 ) , surgical masks ( Hu et al, 2020 ; Pasquarella et al, 2020 ; Dargahi et al, 2021 ), PPE of health care worker ( Peyrony et al, 2020 ), used gloves ( Ye et al, 2020 ), PPE of medical staff including aprons and face shields ( Krambrich et al, 2021 ) and outer part of the N-95 masks ( Dargahi et al, 2021 ). In the above studies, only Hu et al (2020) and Krambrich et al (2021) tested viral infectivity. Hu et al (2020) isolated viable virus from the surgical mask of one critically ill patient.…”

“… Hu et al (2020) isolated viable virus from the surgical mask of one critically ill patient. Whereas Krambrich et al (2021) failed in isolating viruses from the samples.…”

SARS-CoV-2 and other airborne respiratory viruses in outdoor aerosols in three Swiss cities before and during the first wave of the COVID-19 pandemic

“…So far, many studies have detected the presence of SARS-CoV-2 RNA in indoor aerosols, mainly in hospitals ( Ang et al, 2022 , Baboli et al, 2021 , Barbieri et al, 2021 , Bazzazpour et al, 2021 , Cheng et al, 2020 , Chia et al, 2020 , Ding et al, 2021 , Dumont-Leblond et al, 2020 , Feng et al, 2021 , Ghaffari et al, 2021 , Guo et al, 2020 , Habibi et al, 2021 , Hemati et al, 2021 , Kenarkoohi et al, 2020 , Lednicky et al, 2020a , Lednicky et al, 2020b ; Liu et al, 2020 , Lopez et al, 2021 , Nor et al, 2021 , Passos et al, 2021 , Razzini et al, 2020 , Stern et al, 2021a , Stern et al, 2021b ; Tan et al, 2020 , Yarahmadi et al, 2021 , Zhou et al, 2021 ), as well as in residential rooms ( Nannu Shankar et al 2022 ), transportation ( Hadei et al, 2021 , Lednicky et al, 2021 , Moreno et al, 2021 ) and other public indoor places ( Hadei et al 2021 ). Some further detected the presence of SARS-CoV-2 nucleocapsids ( Krambrich et al 2021 ) or even viable viruses ( Lednicky et al, 2020a , Lednicky et al, 2021 ). However, there are much fewer studies focusing on outdoor aerosols ( Chirizzi et al, 2021 , Dunker et al, 2021 , Kayalar et al, 2021 , Linillos-Pradillo et al, 2021 , Passos et al, 2021 , Pivato et al, 2021 , Senatore et al, 2021 , Setti et al, 2020b ), and even fewer which successfully detected the viral RNA ( Kayalar et al, 2021 , Liu et al, 2020 , Setti et al, 2020b , Stern et al, 2021a ).…”