WHO acknowledges ‘evidence emerging’ of airborne spread of COVID-19

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Beds are pictured inside a newly built recovery centre for Covid-19 coronavirus patients, in Mumbai on July 7, 2020. India on July 6 became the country with the third-highest coronavirus caseload in the world, as a group of scientists said there was now overwhelming evidence that the disease can be airborne -- and for far longer than originally thought. (AFP)
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The World Health Organization acknowledges that there is "emerging evidence" on airborne transmission of the new coronavirus, after an international group of scientists said it could spread far beyond two metres. (AFP)
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Updated 07 July 2020

WHO acknowledges ‘evidence emerging’ of airborne spread of COVID-19

  • WHO previously said the virus spreads through droplets expelled from the nose and mouth that quickly sink to the ground
  • New evidence shows floating virus particles can infect people who breathe them in

GENEVA: The World Health Organization on Tuesday acknowledged “evidence emerging” of the airborne spread of the novel coronavirus, after a group of scientists urged the global body to update its guidance on how the respiratory disease passes between people.
“We have been talking about the possibility of airborne transmission and aerosol transmission as one of the modes of transmission of COVID-19,” Maria Van Kerkhove, technical lead on the COVID-19 pandemic at the WHO, told a news briefing.
The WHO has previously said the virus that causes the COVID-19 respiratory disease spreads primarily through small droplets expelled from the nose and mouth of an infected person that quickly sink to the ground.
But in an open letter to the Geneva-based agency, published on Monday in the Clinical Infectious Diseases journal, 239 scientists in 32 countries outlined evidence that they say shows floating virus particles can infect people who breathe them in.
Because those smaller exhaled particles can linger in the air, the scientists are urging WHO to update its guidance.
Speaking at Tuesday’s briefing in Geneva, Benedetta Allegranzi, the WHO’s technical lead for infection prevention and control, said there was evidence emerging of airborne transmission of the coronavirus, but that it was not definitive.
.”..The possibility of airborne transmission in public settings — especially in very specific conditions, crowded, closed, poorly ventilated settings that have been described, cannot be ruled out,” she said.
“However, the evidence needs to be gathered and interpreted, and we continue to support this.”
Any change in the WHO’s assessment of risk of transmission could affect its current advice on keeping 1-meter (3.3 feet) of physical distancing. Governments, which rely on the agency for guidance policy, may also have to adjust public health measures aimed at curbing the spread of the virus.
Van Kerkhove said the WHO would publish a scientific brief summarising the state of knowledge on modes of transmission of the virus in the coming days.
“A comprehensive package of interventions is required to be able to stop transmission,” she said.
“This includes not only physical distancing, it includes the use of masks where appropriate in certain settings, specifically where you can’t do physical distancing and especially for health care workers.”


UK scientists to test extent of airborne COVID-19 transmission

Updated 45 min 4 sec ago

UK scientists to test extent of airborne COVID-19 transmission

  • COVID-19 is known to be present in droplets produced from the mouth and nose from people coughing, sneezing, talking or just breathing
  • Findings could affect governments’ safety measures based on climate, air quality

LONDON: A team of UK scientists is set to discover how long COVID-19 can survive in airborne particles.
In an experiment slated to commence on Monday, researchers at the University of Bristol will test whether the virus is at its most virulent in respiratory droplets, or whether it remains active over significant periods in tiny aerosol particles.
COVID-19 is known to be present in droplets produced from the mouth and nose from people coughing, sneezing, talking or just breathing.
But these remain airborne, and therefore active, for a much shorter period of time than aerosol particles before dropping to the floor.
This is the reasoning behind multiple governments’ enforcing social-distancing measures of 2 meters, among other things. 
But were the virus able to survive in much smaller aerosol particles, it is possible that it could travel greater distances — carried by air currents and ventilation systems — and infect more people, rendering social-distancing measures less effective. 
The theory has gained traction as examples from across the world of groups of people being infected despite observing social-distancing measures, or doing so in poorly ventilated spaces.
Prof. Jonathan Reid, who is leading the Bristol team, told The Guardian newspaper: “We know that when bacteria or viruses become airborne in respiratory droplets they very quickly dry down and can lose viability, so that’s an important step to understand when assessing the role of airborne transmission in COVID-19.”
Allen Haddrell, a scientist at the University of Bristol, said: “We can effectively mimic a cold, wet British winter — or even a hot, dry summer in Saudi Arabia — to look at how these dramatic differences in environmental conditions affect how long the virus remains infectious while suspended in air.”
Results will possibly ready by the end of the week for external scrutiny by the broader scientific community.
Despite excitement surrounding the experiment, some scientists have urged caution, especially regarding the scope of practical applications that could result from it.
“I think the science is fine, and will show the principal that you can modify the environment to reduce the survivability of the virus,” said Dr. Julian Tang, a consultant virologist at Leicester Royal Infirmary.
“But the applicability might be tricky, depending on the environmental factors they identify. You’re not going to sit in a theater or cinema if the temperature is 35 degrees and the humidity is 80 percent.”