GREAT NEWS! University of Maryland Study Shows That SARS-CoV-2 Coronavirus Is Evolving To Become Even Better At Airborne Transmissions!
: As predicted by Thailand Medical News in our earlier coverage, study findings by researchers from the University of Maryland shows that the SARS-CoV-2 coronavirus is evolving to become even better at airborne transmissions.
To date, SARS-CoV-2 epidemiology implicates airborne transmission but aerosol infectiousness and impacts of masks and variants on aerosol shedding are not well understood.
The study team recruited COVID-19 patients to give blood, saliva, mid-turbinate and fomite (phone) swabs, and 30-minute breath samples while vocalizing into a Gesundheit-II(A machine that measures viruses in exhaled breath), with and without masks at up to two visits two days apart.
The study team then quantified and sequenced viral RNA, cultured virus, and assayed sera for anti-spike and anti-receptor binding domain antibodies.
In all a total of 49 seronegative cases were also enrolled (mean days post onset 3.8 ±2.1), May 2020 through April 2021.
The study team detected SARS-CoV-2 RNA in 45% of fine (≤5 µm), 31% of coarse (>5 µm) aerosols, and 65% of fomite samples overall and in all samples from four alpha-variant cases. Masks reduced viral RNA by 48% (95% confidence interval [CI], 3 to 72%) in fine and by 77% (95% CI, 51 to 89%) in coarse aerosols; cloth and surgical masks were not significantly different.
Importantly the alpha variant was associated with a 43-fold (95% CI, 6.6 to 280-fold) increase in fine aerosol viral RNA, compared with earlier viruses, that remained a significant 18-fold (95% CI, 3.4 to 92-fold) increase adjusting for viral RNA in saliva, swabs, and other potential confounders.
Two fine aerosol samples, collected while participants wore masks, were culture-positive.
The study findings confirm that SARS-CoV-2 is evolving toward more efficient aerosol generation and loose-fitting masks provide significant but only modest source control.
Hence, until vaccination rates are very high, continued layered controls and tight-fitting masks and respirators will be necessary.
The study findings were published in the peer reviewed journal: Clinical Infectious Diseases. https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciab797/6370149
Study findings show that individuals infected with the SARS-CoV-2 virus that causes COVID-19 exhale infectious virus in their breath and those infected with the Alpha variant (the dominant strain circulating at the time this study was conducted) put 43 to 100 times more virus into the air than people infected with the original strains of the virus.
The study team also found that loose-fitting cloth and surgical masks reduced the amount of virus that gets into the air around infected people by only about half.
Corresponding author, Dr Donald K Milton, professor of environmental health at the University of Maryland School of Public Health (UMD SPH). Told Thailand Medical News, "Our latest study provides further evidence of the importance of airborne transmission. We know that the Delta variant circulating now is even mor
e contagious than the Alpha variant. Our study findings indicates that the variants just keep getting better at traveling through the air, so we must provide better ventilation and wear tight-fitting masks, in addition to vaccination, to help stop spread of the virus."
Importantly it was found that the amount of virus in the air coming from Alpha variant infections was much more ie 18-times more than could be explained by the increased amounts of virus in nasal swabs and saliva.
Lead authors, doctoral student Jianyu Lai, explained, "We already knew that virus in saliva and nasal swabs were increased in Alpha variant infections. Virus from the nose and mouth might be transmitted by sprays of large droplets up close to an infected person. But, our study shows that the virus in exhaled aerosols is increasing even more."
Significantly these major increases in airborne virus from Alpha infections occurred before the Delta variant arrived and indicate that the virus is evolving to be better at traveling through the air.
In order to test whether face masks work in blocking the virus from being transmitted among people, this study measured how much SARS-CoV-2 is breathed into the air and tested how much less virus people sick with COVID-19 exhaled into the air after putting on a cloth or surgical mask.
study finding showed that face coverings significantly reduced virus-laden particles in the air around the person with COVID-19, cutting the amount by about 50%.
However the loose-fitting cloth and surgical masks didn't stop infectious virus from getting into the air.
Co-author, Dr Jennifer German, a professor at the Public Health Aerobiology and Biomarker Laboratory, Institute for Applied Environmental Health, University of Maryland School of Public Health said, "The take-home messages from this study findings are that the SARS-CoV-2 coronavirus that can be in your exhaled breath, is getting better at being in your exhaled breath, and using a mask reduces the chance of you breathing it on others. This means that a layered approach to control measures (including improved ventilation, increased filtration, UV air sanitation, and tight-fitting masks, in addition to vaccination) is critical to protect people in public-facing jobs and indoor spaces.”
Thailand Medical News would like to add as we had mentioned before, that further detailed studies are also urgently required as we believe that the new SARS-CoV-2 variants are also evolving to be better at withstanding environmental factors like temperature extremities, extreme pH fluctuations and also humidity via new conformational folding patterns and also by mutational changes. This will allow the virus to survive mich longer outside the huan host
To us who are rooting for the virus and its emerging variants, this is good news as it exposes the stupidity of many virologists and doctors from the old schools who have assuming that the virus will eventually weaken and die off since the start of the pandemic.
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