Detection of SARS-CoV-2 in the indoor air of intensive care unit (ICU) for severe COVID-19 patients and its surroundings: considering the role of environmental conditions

Abstract

Graphical abstract There is ambiguity about the airborne transmission of the SARS-CoV-2. While a distance of 6 feet is considered a safe physical distance, new findings show that the virus can be transmitted more than that distance and cause infection. In hospitals, this may cause the virus to be transmitted from the treatment wards of COVID-19 patients to adjacent wards and infect medical staff, non-COVID-19 patients, and patient companions. The aim of this study was to investigate the presence of coronavirus in the air of ICU and adjacent wards. The low volume sampler (LVS) with two separate inlets for PM2.5 and PM10 was applied to collect indoor air of intensive care unit (ICU) with confirmed COVID- 19 patients and its surroundings. The samples were collected on 0.3μ PTFE filter fitted to the holder. Sampling was done at flow rate of 16.7 l/min for 24 h. The SRAS-CoV-2 virus was isolated using a SinaPure™ Virus Extraction Kit (SINACLON, Iran). The presence of SARS-CoV-2 genome was assessed using a commercially available SARS-CoV-2 Test Kit (Pishtaz-Iran), according to the manufacturer’s instructions using One Step plus Real-Time PCR system tool (Applied Biosystems, USA). A total of sixteen samples were taken, and the positive test rate for SRAS-CoV-2 was 12.5 % (2/16). All samples from surrounding (rest room and hallway) were negative, but two air samples from indoor of ICU (next to the patient bed and nursing station) were found to be positive. The results support the possibility of transmitting the SRAS-CoV-2 through the air at a greater distance than what is known as a safe physical distance. Therefore, in addition to maintaining a safe physical distance, other precautions including wearing a face mask, preventing air recirculation, and maximizing the use of natural ventilation should be considered, especially in crowded and enclosed environments. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-021-16010-x.

Ventilation strategies and design impacts on indoor airborne transmission: A review

“…The WHO strongly recommended NV to reduce infection risks after an overview of studies about the influences of NV on reducing infections in indoor spaces [ 40 ]. However, although NV has been recognized as a valuable ventilation strategy to remove aerosols [ 40 , 131 ], it is not commonly applied in clinical and commercial environments, probably because of some disadvantages: inconsistent airflow, concentrations of particles, unstable ventilation rate, and less thermal comfort, particularly in severe climates [ 71 , [132] , [133] , [134] , [135] , [136] ]. NV is also not adequate for high occupancy intensity [ 137 ].…”

A Call to Action: Reinvigorating Interest and Investments in Health Infrastructure

“…For reducing transmission in health care facilities, adequate air filtration and ventilation are paramount 30 , 31 alongside management of patient flow and personal protective equipment for health care workers. The increased use of intensive care units in the face of COVID-19 further stresses the need for health infrastructure.…”

“…27 However, efforts to scale up oxygen are underway, 28 and the WHO COVID-19 Essential Supplies Forecasting Tool (https://apps.who.int/ iris/rest/bitstreams/1342089/retrieve) can help to estimate needs for oxygen and other equipment, supplies, and drugs for care and treatment of COVID-19. In addition, recommen-dations for managing patient oxygen needs in resourceconstrained settings are compiled and summarized by Serpa Neto et al 29 For reducing transmission in health care facilities, adequate air filtration and ventilation are paramount 30,31 alongside management of patient flow and personal protective equipment for health care workers. The increased use of intensive care units in the face of COVID-19 further stresses the need for health infrastructure.…”

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

“…Thus, surveillance of virus-laden aerosols is suitable for monitoring this path and assessing qualitative and quantitative molecular epidemiological information on population exposure to SARS-CoV-2 ( Anand et al 2021 ). 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 ).…”