COVID Breakfast

C

I haven’t done this for a while so whilst you are eating your cornflakes have a chuckle, but having ventured into a Garden Centre on Sunday, to witness some idiot cough his way through the shop, this paper took my attention about infectivity from a sneeze, a cough and breathing. The take home message is be cautious.

We are told that the virus is spread by aerosols but after sunday, I think aerosols is spelt differently, it is more likely to be spread by R-soles. So if you have a cough….be considerate to others and stay at home until it clears and if someone is coughing remember they could be infective.

Exposure assessment for airborne transmission of SARS-CoV-2 via breathing, speaking, coughing and sneezingSchijven, J. F., Vermeulen, L. C., Swart, A., Meijer, A., Duizer, E., de Roda Husman, A. M.10.1101/2020.07.02.20144832 — Posted: 2020-07-05

Background Evidence for indoor airborne transmission of SARS-CoV-2 is accumulating. If SARS-CoV-2 also spreads via aerosols, this has implications for measures taken to limit transmission.

Objectives The aim of this study is to assess exposure to airborne SARS-CoV-2 particles from breathing, speaking, coughing and sneezing in an indoor environment.

Methods An exposure assessment model was developed to estimate numbers of SARS-CoV-2 particles in aerosol droplets, expelled during breathing, speaking, coughing and sneezing by an infected person in an unventilated indoor environment, and subsequent inhalation by one or more persons. Scenarios encompass a range of virus concentrations, room sizes and exposure times.

Results The calculated total volume of expelled aerosol droplets was highest for a sneeze, followed by a cough and speaking for 20 minutes, and lastly breathing for 20 minutes. A few to as much as tens of millions of virus particles were expelled. Exposure probability strongly depends on the viral concentration in mucus, as well as on the scenario. Exposure probabilities were generally below 1% at a virus concentration in mucus below 10^5 per mL for all scenarios, increasing steeply at different higher concentrations. According to nose / throat swab data collected from patients, 75%, 50% and 5% of infected individuals carry an estimated number of SARS-CoV-2 per mL mucus of at least 10^5, 10^6 and 10^8, respectively.

Discussion Exposure to SARS-CoV-2 via aerosols generated during breathing, speaking, coughing and sneezing in an unventilated indoor environment is possible. This study forms a basis to estimate probabilities of exposure to SARS-Cov-2 by airborne transmission in indoor spaces. As long as it is uncertain what fraction of the airborne virus particles is infectious and as long as a dose-response relation is lacking, it is recommended to be precautious.

And one for ProfG

Covid-19 Risk Among Airline Passengers: Should the Middle Seat Stay Empty?barnett, a.10.1101/2020.07.02.20143826 — Posted: 2020-07-05

Recent research results and data generate the approximation that, when all coach seats are full on a US jet aircraft, the risk of contracting Covid-19 from a nearby passenger is currently about 1 in 7,000. Under the middle seat empty policy, that risk falls to about 1 in 14,000. Risks are lower in flights that are not full. These estimates imply Covid-19 mortality risks to uninfected air travelers are higher than those associated with plane crashes but probably less than one in one million.

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MouseDoctor

10 comments

  • Ahh Mousedoctor, you crack me up! 🤣 But you are right, a little more consideration Towards others would go a long way.

  • From what I heard on Radio 4’s PM programme yesterday, including an interview with Dr Julian Tang, 230 scientists have written to the WHO asking that they give more priority to airborne transmission of COVID-19. I never understood the dogged emphasis on handwashing (only).

    Thought this was interesting:
    “Dr Julian Tang of the University of Leicester has come up an easy ‘breath test’ to check if you’re too close to colleagues.

    A consultant virologist at Leicester Royal Infirmary, he’s studied how the air is moved when people speak and concludes that something as simple as a conversation could pass the virus.

    ‘If you can smell your friend’s breath – the garlic or curry or alcohol – you’re inhaling what they’re breathing out.

    ‘And if you’re inhaling enough of that air to smell it, then you’re close enough to inhale any virus that’s also carried in the air with it.'”

    https://www.bbc.co.uk/news/science-environment-52804795

    • I suspect it is a case of show me the (Grant) money!

      A breathaliser for COVID really…the 1m/2m rule is like 5 a day, its just made up…I have been sweated on my a jogger do they and dog walkers care about Social distancing and yes I am generalising?

      All you have to do is read and watch there have been upteen reports on airborne infection and upteen studies showing the spread of airbourne droplets and until people get it that the wearing of masks is to there to reduce your spread of particle. There will be unintentional preventable spreading

      I suspect the UK government was worried that if they said wear a mask there would have been no PPE for frontline staff, their whole approach to this type of public information shows their advisors can’t read or that Dominic Cummins doesn’t listen to the medical advisors. We have been treated like young children in this respect and you have been fed bo**ocks by the media.

      It is simply anti-science to susggest that there is no value of mask wearing both from limiting you getting infection and stopping you giving infection to others. If this were not the case Hospitals would not be bothering with PPE.

      • Yes. Although I’m not sure a crappy disposable mask is stopping me smelling garlic breath. According to Dr Tang, from what I understood, WHO didn’t emphasise airborne transmission because they couldn’t fund all the masks for poorer areas of the globe.

        • It is too late the COVID grants were all snaffled up by people on the inside, before they went live, so business as usual. Those in receipt of government funds could divert it to covid work as for the grant title there are some real corkers

          “We will create the technologies, skill-sets and trained personnel needed to enable UK manufacturers to deliver the promise of advanced medical precision and patient screening. The xxxxxxxx Hub and its research and translational spokes will network with industrial users to create and apply the necessary novel methods of process development and manufacture. Hub tools will transform supply chain economics for targeted healthcare, and novel manufacturing, formulation and control technologies for stratified and personalised medicines. The Hub will herald a shift in manufacturing practice, provide the engineering infrastructure needed for sustainable healthcare. The UK economy and Society Well being will gain from enhanced international competitiveness.” = All for a meer £10.3 million….Kerr Ching

          Would you rather have remyelination or “Identifying genetic and structural similarities between SARS-CoV-2, the coronavirus that causes COVID-19, and measles, mumps, and rubella (MMR)”.

          • That little beauty is classic example of business-style jargon-speak with every cliche in the book.

            Kerching indeed.
            Scraps for the rest of us.

    • The studies have shown that roughly 45-50 % of patients are asymptomatic but after further interviews with patients they indicated that they may have felt a slight increase in temperature or a mild fatigue but didn’t think much about it.

      But even so, these asymptomatic patients are shedding the virus for 10-14 days. Patients with more sever disease shed for up to 4 weeks with higher viral loads. Asymptomatic patients have a lower viral load than symptomatic patients but may not take proper precautions such as wearing a face covering. So while aerosols from patients may extend more than 2 meters, the viral load value is important for transmissibility. In any event, wear a face covering.

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