COVID-19 Cluster Linked to Aerosol Transmission of SARS-CoV-2 via Floor Drains

Abstract

Background Recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission through exposure to aerosols has been suggested. Therefore, we investigated the possibility of aerosol SARS-CoV-2 transmission within an apartment complex where residents reported testing positive for SARS-CoV-2 despite having no direct contact with other SARS-CoV-2–infected people. Methods Information on symptom onset and exposure history of the patients was collected by global positioning system (GPS) tracking to investigate possible points of contact or spread. Samples collected from patients and from various areas of the complex were analyzed using RNA sequencing. Phylogenetic analysis was also performed. Results Of 19 people with confirmed SARS-CoV-2 infection, 5 reported no direct contact with other residents and were from apartments in the same vertical line. Eight environmental samples tested positive for the virus. Phylogenetic analyses revealed that 3 of the positive cases and 1 environmental sample belonged to the B.1.497 lineage. Additionally, 3 clinical specimens and 1 environmental sample from each floor of the complex had the same amino acid substitution in the ORF1ab region. Conclusions SARS-CoV-2 transmission possibly occurs between different floors of an apartment building through aerosol transmission via nonfunctioning drain traps.

Long distance airborne transmission of SARS-CoV-2: rapid systematic review

“…Fifty six additional reports identified from the Comber et al rapid review 21 and by citation analysis were also assessed. From these 146 reports, 124 were excluded (see supplementary material 1 (section 3) for list of reasons for exclusion), and 22 reports 1 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 relating to 18 studies were included. When two or more reports related to the same study, we considered the most comprehensive report as the main publication.…”

“… 36 Eight studies were conducted in Asia, 34 35 36 37 38 39 40 45 five in Europe, 41 43 44 47 48 three in Oceania, 32 33 46 and two in the United States. 1 42 Three studies reported on transmission between flats in apartment blocks, 38 39 40 two in quarantine hotels, 32 33 two in restaurants, 34 35 two in buses, 36 37 one in a food processing factory, 41 one in a courtroom, 43 one in an office, 44 one in a fitness facility, 42 one in a department store, 45 and four during singing events. 1 46 47 48 All the outbreaks occurred in 2020, except for one in January 2021 in South Korea 40 (before vaccine rollout started in this country) and one in July 2021 in a quarantine hotel in New Zealand.…”

“…Figure 2 provides details of the methodological quality ratings: three studies were rated as high quality, 33 35 46 five as medium quality, 32 34 36 41 47 and 10 as low quality. 1 37 38 39 40 42 43 44 45 48 These ratings represent the methodological quality of descriptive studies.…”

Evaluating SARS‐CoV‐2 airborne quanta transmission and exposure risk in a mechanically ventilated multizone office building

“…7 ). Vertical transmission evidence for the SARS-CoV-2 has been previously reported [ 36 ]. The VAV system started at 6:00 and turned off at 22:00.…”

“…Empirical evidence has been reported for aerosol zonal transmission in an Eastern Canadian hospital [ 35 ]. Taewon et al [ 36 ] have also suggested the possibility of SARS-CoV-2 transmission between different floors of an apartment building. In their epidemiology investigation, five of nineteen reported cases claimed no direct contact with other residents in the building.…”