key: cord-0835110-n7a0ttqz authors: Moharir, Shivranjani C.; Sharath Chandra, T.; Goel, Arushi; Thakur, Bhuwaneshwar; Tandel, Dixit; Reddy Mahesh, S.; Vodapalli, Amareshwar; Singh Bhalla, Gurpreet; Kumar, Dinesh; Singh Naruka, Digvijay; Kumar, Ashwani; Tuli, Amit; Suravaram, Swathi; Chander Bingi, Thrilok; Srinivas, M.; Mesipogu, Rajarao; Reddy, Krishna; Khosla, Sanjeev; H Harshan, Krishnan; Bharadwaj Tallapaka, Karthik; K Mishra, Rakesh title: Detection of SARS-CoV-2 in the air in Indian hospitals and houses of COVID-19 patients date: 2022-04-26 journal: J Aerosol Sci DOI: 10.1016/j.jaerosci.2022.106002 sha: d33460e85436802c50657b83851eb0d88d3a00bb doc_id: 835110 cord_uid: n7a0ttqz To understand the transmission characteristics of severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) through air, samples from different locations occupied by coronavirus disease (COVID-19) patients were analyzed. Three sampling strategies were used to understand the presence of virus in the air in different environmental conditions. In the first strategy, which involved hospital settings, air samples were collected from several areas of hospitals like COVID-intensive-care units (ICUs), nurse-stations, COVID-wards, corridors, non-COVID-wards, personal protective equipment (PPE) doffing areas, COVID rooms, out-patient (OP) corridors, mortuary, COVID casualty areas, non-COVID ICUs and doctors’ rooms. Out of the 80 air samples collected from 6 hospitals from two Indian cities- Hyderabad and Mohali, 30 samples showed the presence of SARS-CoV-2 nucleic acids. In the second sampling strategy, that involved indoor settings, one or more COVID-19 patients were asked to spend a short duration of time in a closed room. Out of 17 samples, 5 samples, including 4 samples collected after the departure of three symptomatic patients from the room, showed the presence of SARS-CoV-2 nucleic acids. In the third strategy, involving indoor settings, air samples were collected from rooms of houses of home-quarantined COVID-19 patients and it was observed that SARS-CoV-2 RNA could be detected in the air in the rooms occupied by COVID-19 patients but not in the other rooms of the houses. Taken together, we observed that the air around COVID-19 patients frequently showed the presence of SARS-CoV-2 RNA in both hospital and indoor residential settings and the positivity rate was higher when 2 or more COVID-19 patients occupied the room. In hospitals, SARS-CoV-2 RNA could be detected in ICUs as well as in non-ICUs, suggesting that the viral shedding happened irrespective of the severity of the infection. This study also provides evidence for the viability of SARS-CoV-2 and its long-range transport through the air. Thus, airborne transmission could be a major mode of transmission for SARS-CoV-2 and appropriate precautions need to be followed to prevent the spread of infection through the air. Abstract: 23 To understand the transmission characteristics of severe acute respiratory syndrome corona The ~100nm viral particle, SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2 58 has affected different aspects of human life in multiple ways (Bar-On, Flamholz et al. 2020). 59 The effects on the patient are not only restricted to the dysfunction of the respiratory system 60 but are seen to range from the patient being totally asymptomatic to respiratory or multiorgan To get further insights on transmission characteristics of SARS-CoV-2 in air in hospital and 102 indoor residential settings, and to assess the risk for healthcare workers and the caretakers, we were present in the room, they were positioned in such a manner that the distance between 220 each participant and the air sampler was same. SARS-CoV-2 RNA was detected 5 out of 17 221 samples collected (Table 2) . Importantly, samples collected post departure of the patients 222 from the room were also positive for SARS-CoV-2 RNA. was positive for SARS-CoV-2 RNA, whereas all other air samples were negative (Table 3) . The second family consisted of 5 members, of which 2 were reported COVID-19 positive one 250 day prior to the study (Table 3) . Both had fever previously, but were asymptomatic during the (Table 3) . The third family consisted of 6 members (Table 3 ). Prior to the study, only 2 members were 263 known to be positive for SARS-CoV-2. The family members did not wear mask at home, 264 were not room quarantined and interacted with each other verbally during the sampling event. On the first day of sampling, nasopharyngeal swabs were collected from all the six members 266 and all of them were found to be positive for COVID-19 (Supplementary/ Data in brief Table 267 4). Air samples were collected from 1.5 and 3 meter from patient 1, who was previously 268 known to be positive. Both the air samples were found to be positive for SARS-CoV-2 RNA. Another air sample, collected from the bedroom of patient 1, which was unoccupied by the 270 patient during sample collection, was found to be positive for SARS-CoV-2 RNA. The room 271 was vacated by the patient at least 2 hours before sample collection, indicating that, SARS- CoV-2 can stay in the air of closed rooms for at least 2 hours. Next day, another four air 273 samples, collected from the hall and dining room occupied by the COVID-19 positive individuals, and bathroom and bedroom, previously occupied, but unoccupied during sample 275 collection, were found to be positive for SARS-CoV-2 RNA (Table 3) . Table 5 . Table 4 ). The virus could not be detected in any of the non-COVID care areas. The positivity rate was found to be more when the number of COVID patients were higher in the room. The 302 SARS-CoV-2 RNA positivity percentage was 58% when 2 or more COVID-19 patients were 303 present in a room, in contrast to 24.62% when 1 or 0 COVID-19 patients occupied the room. (P = 0.0185; Table 5 ). A point to be highlighted from the hospital experiments was that in 305 many of SARS-CoV-2 RNA positive samples, the air sampler was at least 8 feet away from 306 the nearest patient. As there is no record on events that occurred in the sampling area before and non-ICU groups, using Odd's ratio with 95% confidence interval. 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