Nosocomial Outbreak of Coronavirus Disease 2019 by Possible Airborne Transmission Leading to a Superspreading Event

Abstract

Background Nosocomial outbreaks with superspreading of COVID-19 due to a possible airborne transmission has not been reported. Methods Epidemiological analysis, environmental samplings, and whole genome sequencing (WGS) were performed for a hospital outbreak. Results A superspreading event involving 12 patients and 9 healthcare workers (HCWs) occurred within 4 days in 3 of 6 cubicles at an old-fashioned general ward with no air exhaust built within the cubicles. The environmental contamination by SARS-CoV-2 RNA was significantly higher in air grilles (>2m from patients’ head and not reachable by hands) than high-touch clinical surfaces (36.4%, 8/22 vs 3.4%, 1/29, p=0.003). Six (66.7%) of 9 contaminated air exhaust grilles were located outside patient cubicle. The clinical attack rate of patients was significantly higher than HCWs (15.4%, 12/78 exposed-patients vs 4.6%, 9/195 exposed-HCWs, p=0.005). Moreover, clinical attack rate of ward-based HCWs was significantly higher than non-ward-based HCWs (8.1%, 7/68 vs 1.8%, 2/109, p=0.045). The episodes (mean ± S.D) of patient-care duty assignment in the cubicles was significantly higher among infected ward-based HCWs than non-infected ward-based HCWs (6.0±2.4 vs 3.0±2.9, p=0.012) during the outbreak period. The outbreak strains belong to SARS-CoV-2 lineage, B.1.36.27 (GISAID Clade GH) with the unique S-T470N mutation on WGS. Conclusion This nosocomial point source superspreading due to possible airborne transmission demonstrated the need for stringent SARS-CoV-2 screening at admission to healthcare facilities and better architectural design of the ventilation system to prevent such outbreaks. Portable high-efficiency particulate filters were installed in each cubicle to improve ventilation before resumption of clinical service.

Orthodoxy, illusio, and playing the scientific game: a Bourdieusian analysis of infection control science in the COVID-19 pandemic

“…However, Japan was not alone, as a number of Asian countries more quickly accepted the possibility of airborne spread and incorporated face mask use into its pandemic response 5 . Nor was the public health response a monolithic one, as some infection control experts have cited the precautionary principle, helped to promote more widespread face mask use and sought to obtain more robust evidence of airborne transmission 6,7 . As early as April 2020, an advisory report from the National Academies to the U.S. Office of Science and Technology Policy concluded that "the results of available studies are consistent with aerosolization of virus from normal breathing" 8 .…”

“…We acknowledge that not all scientists accept the statements in the previous paragraph -see for example 6,7 . Indeed, nonacceptance of the theory of airborne spread is the central focus of this paper.…”

Complementation of contact tracing by mass testing for successful containment of beta COVID-19 variant (SARS-CoV-2 VOC B.1.351) epidemic in Hong Kong

“…35 Timely use of whole genome sequencing can greatly facilitate outbreak investigation, not only to understand the cryptic chain of transmission, 36 but also to explore the possible mode of transmission. 37 The source of SARS-CoV-2 VOC B.1.351 acquisition for the index case remains to be resolved. When he was under quarantine in the designated hotel, a person staying in the adjacent room was diagnosed to have SARS-CoV-2 VOC B.1.351 (potential case 0).…”

Nosocomial Outbreak of COVID-19 in a Hematologic Ward

“…SARS-CoV-2 infection in hospitalized patients with underlying disease is associated with a poor prognosis, and rapid SARS-CoV-2 transmission makes containment of the outbreak challenging. In addition, there is growing evidence for airborne-transmission of SARS-CoV-2 [ 1 2 3 4 ] and previous studies suggest that thorough investigation should be performed including the possibility of airborne-transmission [ 5 6 7 ].…”