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.