A super-spreader of COVID-19 in Ningbo city in China

Lin, Jie; Yan, Kun; Zhang, Jingfeng; Cai, Ting; Zheng, Jianjun

doi:10.1016/j.jiph.2020.05.023

Cited by 44 publications

(53 citation statements)

References 3 publications

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“…Heterogeneity of SARS-CoV-2 transmission poses challenges to the implementation of an effective containment strategy, and its adjustment in response to the evolving pandemic. Heterogeneous virus spread was postulated to be associated with high viral shedding of superspreaders, [8] as shown in reported cases [5] . The pattern of superspreading events may however vary between outbreaks, and superspreaders could be unidentified or identified only after the event.…”

Section: Introductionmentioning

confidence: 91%

“…Amidst the widespread dissemination of COVID-19, marked heterogeneity of SARS-CoV-2’s transmission pattern is noted, [1] as has been described for the related virus causing SARS over a decade ago [2] . Modelling studies suggested the phenomenon of overdispersion, with 80% of the secondary transmission caused by a very small fraction of proportion of SARS-CoV-2 infected patients, [3] which explains the characteristics of outbreaks attributed to a single patient exposure, [4 , 5] or inferred from some big clusters as reported in South Korea [6] and Germany [7] .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Settings of virus exposure and their implications in the propagation of transmission networks in a COVID-19 outbreak

Wong

Lee

Kwan

et al. 2020

The Lancet Regional Health - Western Pacific

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Settings of virus exposure and their implications in the propagation of transmission networks in a COVID-19 outbreak

Wong

Lee

Kwan

et al. 2020

The Lancet Regional Health - Western Pacific

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“…However, in recent months the empirical evidence that the six-foot rule is not sufficient to protect against infection with the coronavirus has kept on accumulating and various so-called super-spreading events have been reported, see e.g. [6,[8][9][10][11][27][28][29], all of them indoors. These super-spreading events suggest airborne transmission of the coronavirus [1][2][3][12][13][14], with tremendous implications for the risk assessment of coronavirus transmission.…”

mentioning

confidence: 99%

Extended lifetime of respiratory droplets in a turbulent vapour puff and its implications on airborne disease transmission

Chong

Hori

et al. 2020

Preprint

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To mitigate the COVID-19 pandemic, it is key to slow down the spreading of the life-threatening coronavirus (SARS-CoV-2). This spreading mainly occurs through virus-laden droplets expelled at speaking, screaming, shouting, singing, coughing, sneezing, or even breathing [1-7]. To reduce infections through such respiratory droplets, authorities all over the world have introduced the so-called "2-meter distance rule" or "6-foot rule". However, there is increasing empirical evidence, e.g. through the analysis of super-spreading events [6, 8-11], that airborne transmission of the coronavirus over much larger distances plays a major role [1-3, 7, 12-15], with tremendous implications for the risk assessment of coronavirus transmission. It is key to better and fundamentally understand the environmental ambient conditions under which airborne transmission of the coronavirus is likely to occur, in order to be able to control and adapt them. Here we employ direct numerical simulations of a typical respiratory aerosol in a turbulent jet of the respiratory event within a Lagrangian-Eulerian approach [16-18] with 5000 droplets, coupled to the ambient velocity, temperature, and humidity fields to allow for exchange of mass and heat [19] and to realistically account for the droplet evaporation under different ambient conditions. We found that for an ambient relative humidity of 50% the lifetime of the smallest droplets of our study with initial diameter of 10 μm gets extended by a factor of more than 30 as compared to what is suggested by the classical picture of Wells [20, 21], due to collective effects during droplet evaporation and the role of the respiratory humidity [22], while the larger droplets basically behave ballistically. With increasing ambient relative humidity the extension of the lifetimes of the small droplets further increases and goes up to 150 times for 90% relative humidity, implying more than two meters advection range of the respiratory droplets within one second. Smaller droplets live even longer and travel further. Our results may explain why COVID-19 superspreading events can occur for large ambient relative humidity such as in cooled-down meat-processing plants [10] or in pubs with poor ventilation. We anticipate our tool and approach to be starting points for larger parameter studies and for optimizing ventilation and indoor humidity controlling concepts, which in the upcoming autumn and winter both will be key in mitigating the COVID-19 pandemic.

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“…Social distancing itself is not a way for source control, it is meaningful outdoors, and for indoors without proper ventilation, it only means a false sense of security with potential devastating infection, a bus ride turned into a coronavirus super spreader event is a smoking gun [101].…”

Section: Discussionmentioning

confidence: 99%

Reciprocal Personal/Public Protection for COVID-19 with Facepiece Discriminating Mouth and Nose

Yuan¹

2020

Preprint

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Reciprocal Personal/Public Protection (RPPP) featured with source control is introduced, Facepiece Discriminating Mouth and Nose (FDMN) is employed to serve the purpose, which includes polymer based mouth cover with optional nose cover. The new knowledge that mouth is a primary, active and dominant source of the virus has been well established, which is the base of FDMN. Source classification and related source control tools are discussed, mouth cover is recommended as the tool prioritized to use. Liquid droplets is identified as a hard issue related to mask, liquid droplets, mask fitting, comfort and facial recognition constitute real challenges of mask in addition to efficiency, All of these have been addressed with FDMN. Comparisons between FDMN and masks/face covering are taken on four aspects: efficiency and efficacy, tolerance and comfort, cost and waste, and civil rights and public interest. Mouth cover is recommended to replace the face covering and act as both a personal tool and a public utensil, mouth cover with nose cover can provide better protection than N95 etc. RPPP with FDMN, could be an alternative for lockdown, a parallel strategy to vaccine, and a collectively living way during the pandemic era. FDMN, featured with high efficiency protection, high degree comfort, easy wearing, tight-fitting, easy facial recognition & communication, reusability, cost-effective, environment friendly and scale manufacturing more readily and widely etc., is a simple and sustainable solution, which is essential for ordinary people to keep wearing it properly for protection.

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A super-spreader of COVID-19 in Ningbo city in China

Cited by 44 publications

References 3 publications

Settings of virus exposure and their implications in the propagation of transmission networks in a COVID-19 outbreak

Settings of virus exposure and their implications in the propagation of transmission networks in a COVID-19 outbreak

Extended lifetime of respiratory droplets in a turbulent vapour puff and its implications on airborne disease transmission

Reciprocal Personal/Public Protection for COVID-19 with Facepiece Discriminating Mouth and Nose

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