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Scientists report that airborne coronavirus is probably infectious - ABS-CBN News
Scientists have known for several months the new coronavirus can become suspended in microdroplets expelled by patients when they speak and breathe, but until now there was no proof that these tiny particles are infectious.
Scientists have known for several months the new coronavirus can become suspended in microdroplets expelled by patients when they speak and breathe, but until now there was no proof that these tiny particles are infectious. A new study by scientists at the University of Nebraska that was uploaded to a medical preprint site this week has shown for the first time that SARS-CoV-2 taken from microdroplets, defined as under five microns, can replicate in lab conditions. This boosts the hypothesis that normal speaking and breathing, not just coughing and sneezing, are responsible for spreading COVID-19 -- and that infectious doses of the virus can travel distances far greater than the six feet (two meters) urged by social distancing guidelines. The results are still considered preliminary and have not yet appeared in a peer-reviewed journal, which would lend more credibility to the methods devised by the scientists. The paper was posted to the medrxiv.org website, where most cutting-edge research during the pandemic has first been made public. The same team wrote a paper in March showing that the virus remains airborne in the rooms of hospitalized COVID-19 patients, and this study will soon be published in a journal, according to the lead author. "It is actually fairly difficult" to collect the samples, Joshua Santarpia, an associate professor at the University of Nebraska Medical Center told AFP. The team used a device the size of a cell phone for the purpose, but "the concentrations are typically very low, your chances of recovering material are small." The scientists took air samples from five rooms of bedridden patients, at a height of about a foot (30 centimeters) over the foot of their beds. The patients were talking, which produces microdroplets that become suspended in the air for several hours in what is referred to as an "aerosol," and some were coughing. The team managed to collect microdroplets as small as one micron in diameter. They then placed these samples into a culture to make them grow, finding that three of the 18 samples tested were able to replicate. For Santarpia, this represents proof that microdroplets, which also travel much greater distances than big droplets, are capable of infecting people. "It is replicated in cell culture and therefore infectious," he said. Why we wear masks The potential for microdroplet transmission of the coronavirus was at one stage thought to be improbable by health authorities across the world. Later, scientists began to change their mind and acknowledge it may be a possibility, which is the rationale for universal masking. The World Health Organization was among the last to shift its position, doing so on July 7. "I feel like the debate has become more political than scientific," said Santarpia. "I think most scientists that work on infectious diseases agree that there's likely an airborne component, though we may quibble over how large." Linsey Marr, a professor at Virginia Tech who is a leading expert on aerial transmission of viruses and wasn't involved in the study, said it was rare to obtain measurements of the amount of virus present in air. "Based on what we know about other diseases and what we know so far about SARS-CoV-2, I think we can assume that if the virus is 'infectious in aerosols,' then we can become infected by breathing them in," she told AFP.
Widespread mask-wearing could prevent COVID-19 second wave: study - ABS-CBN News
Population-wide facemask use could push COVID-19 transmission down to controllable levels for national epidemics and could prevent further waves of the pandemic disease when combined with lockdowns, according to a UK study published Wednesday.
LONDON — Population-wide face mask use could push COVID-19 transmission down to controllable levels for national epidemics and could prevent further waves of the pandemic disease when combined with lockdowns, according to a UK study published Wednesday. The research, led by scientists at the Britain's Cambridge and Greenwich Universities, suggests lockdowns alone will not stop the resurgence of the new SARS-CoV-2 coronavirus, but that even homemade masks can dramatically reduce transmission rates if enough people wear them in public. "Our analyses support the immediate and universal adoption of face masks by the public," said Richard Stutt, who co-led the study at Cambridge. He said the findings showed that if widespread mask use were combined with social distancing and some lockdown measures, this could be "an acceptable way of managing the pandemic and re-opening economic activity" long before the development and public availability of an effective vaccine against COVID-19, the respiratory illness caused by the coronavirus. The study's findings were published in the "Proceedings of the Royal Society A" scientific journal. The World Health Organization updated its guidance on Friday to recommend that governments ask everyone to wear fabric face masks in public areas where there is a risk to reduce the spread of the disease. In this study, researchers linked the dynamics of spread between people with population-level models to assess the effect on the disease's reproduction rate, or R value, of different scenarios of mask adoption combined with periods of lockdown. The R value measures the average number of people that one infected person will pass the disease on to. An R value above 1 can lead to exponential growth. The study found that if people wear masks whenever they are in public it is twice as effective at reducing the R value than if masks are only worn after symptoms appear. In all scenarios the study looked at, routine facemask use by 50 percent or more of the population reduced COVID-19 spread to an R of less than 1.0, flattening future disease waves and allowing for less stringent lockdowns. "We have little to lose from the widespread adoption of facemasks, but the gains could be significant," said Renata Retkute, who co-led the study.