Respiratory virus shedding in exhaled breath and efficacy of face masks

This study was undertaken in an outpatient clinic of a private hospital in Hong Kong between March 2013 and May 2016, and has just recently been published in Nature Medicine.  A total of 111 patients infected with human coronavirus (n=17), influenza virus (n=43) and/or rhinovirus (n=54) (three participants had coinfections) formed the focus of theContinue reading “Respiratory virus shedding in exhaled breath and efficacy of face masks”

Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations

The WHO has recently released a scientific briefing on the modes of transmission of the COVID-19 virus, which can be accessed here. What does the briefing cover? The briefing defines the difference between droplets, which are larger than 5 microns and generated by coughing or sneezing, and droplet nuclei, which are less than 5 micronsContinue reading “Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations”

Chemicals and microbes in bioaerosols from reaction tanks of six wastewater treatment plants: survival factors, generation sources, and mechanisms

Wastewater treatment commonly includes the production of air bubbles (aeration) at the bottom of activated sludge or during Dissolved Air Flocculation and Floatation. When the bubbles rise to the surface they burst, form droplets and ‘aerosolise’. This is how pathogenic microorganisms in the wastewater can become ‘airborne’.  The Experiment: Bioaerosol samples were collected from 0.1,Continue reading “Chemicals and microbes in bioaerosols from reaction tanks of six wastewater treatment plants: survival factors, generation sources, and mechanisms”

Detection of Infectious Influenza Virus in Cough Aerosols Generated in a Simulated Patient Examination Room

Bioaerosols are generated during wastewater treatment (eg Wang et al., 2018) and personnel working in public are also at risk of infection through inhaling aerosolised virus. This study describes the working efficacy of a N95 respirator mask (left image) or a surgical mask (right image). The Experiment: A mechanical dummy which coughed infectious influenza virusContinue reading “Detection of Infectious Influenza Virus in Cough Aerosols Generated in a Simulated Patient Examination Room”

Exhaled Air Dispersion during Coughing with and without Wearing a Surgical or N95 Mask

This study gives information about surgical mask containment of particles coughed out by an infected person and is relevant to personnel who have to work amongst potentially infectious members of the public who may or may not be wearing masks. In this study a dummy of a 70kg man enclosing a mechanical lung model forContinue reading “Exhaled Air Dispersion during Coughing with and without Wearing a Surgical or N95 Mask”

An Imperative Need for Research on the Role of Environmental Factors in Transmission of Novel Coronavirus (COVID-19)

On this blog, we have previously highlighted the recently produced open access Environmental Science and Technology ‘virtual issue’, collating numerous years of research on the fate and behaviour of enveloped viruses in the environment. This virtual issue includes a current “scientific opinion” (non-peer reviewed) piece by four researchers, Guangbo Qu (Chinese Academy of Sciences), XiangdongContinue reading “An Imperative Need for Research on the Role of Environmental Factors in Transmission of Novel Coronavirus (COVID-19)”

Stability of SARS-CoV-2 as compared with SARS-CoV-1

This study examined the survival and infectivity of SARS-CoV-2 (COVID-19) and SARS-CoV-1 in air and on solid surfaces. A concentration in the same ballpark as the amount coughed out by an infected person was incorporated into aerosolised droplets which were either kept inside an enclosed drum for 3 hours, or were deposited onto stainless steel,Continue reading “Stability of SARS-CoV-2 as compared with SARS-CoV-1”