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Post by Admin on Jul 13, 2020 19:09:03 GMT
Under pressure from the scientific community, the World Health Organization acknowledged last week the airborne transmission of "micro-droplets" as a possible third cause of COVID-19 infections. To many researchers in Japan, the admission felt anti-climactic. This densely populated country has operated for months on the assumption that tiny, "aerosolized" particles in crowded settings are turbo-charging the spread of the new coronavirus. Very few diseases — tuberculosis, chicken pox and measles — have been deemed transmissible through aerosols. Most are spread only through direct contact with infected persons or their bodily fluids, or contaminated surfaces. WHO chief warns coronavirus pandemic "accelerating" Still the WHO has refused to confirm aerosols as a major source of new coronavirus infections, saying more evidence is needed. But scientists are keeping the pressure on. "If the WHO recognizes what we did in Japan, then maybe in other parts of the world, they will change (their antiviral procedures)," said Shin-Ichi Tanabe, a professor in the architecture department of Japan's prestigious Waseda University. He was one of the 239 international scientists who co-wrote an open letter to the WHO urging the United Nations agency to revise its guidelines on how to stop the virus spreading. Large droplets expelled through the nose and mouth tend to fall to the ground quickly, explained Makoto Tsubokura, who runs the Computational Fluid Dynamics lab at Kobe University. For these larger respiratory particles, social distancing and face masks are considered adequate safeguards. But in rooms with dry, stale air, Tsubokura said his research showed that people coughing, sneezing, and even talking and singing, emit tiny particles that defy gravity — able to hang in the air for many hours or even days, and travel the length of a room. The key defense against aerosols, Tsubokura said, is diluting the amount of virus in the air by opening windows and doors and ensuring HVAC systems circulate fresh air. In open-plan offices, he said partitions must be high enough to prevent direct contact with large droplets, but low enough to avoid creating a cloud of virus-heavy air (55 inches, or head height.) Small desk fans, he said, can also help diffuse airborne viral density. To the Japanese, the latest WHO admission did at least vindicate a strategy that the country adopted in February, when residents were told to avoid "the three Cs" — cramped spaces, crowded areas and close conversation.
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Post by Admin on Sept 20, 2020 19:28:13 GMT
Mutant strains of COVID-19 that are more contagious, but less serious, have turned up in France, possibly explaining why Europe is reporting a spike in confirmed cases. The chief of a leading French research hospital revealed the discovery to French lawmakers last week, the Sunday Times of London reported. Microbiologist Didier Raoult, who heads IHU Méditerranée Infection in Marseilles, told senators that the hospital’s infectious disease experts found seven coronavirus mutations during an analysis of COVID-19 tests over the summer. One strain, Raoult theorized, was brought in by people coming from North Africa after France lifted its lockdown in June. The mutation has now disappeared, though others have popped up, the outlet reported. “They are less severe, so something is happening with this virus, which makes it different,” Raoult testified. “The mutations we have are a rather degraded version of the initial form. At least that is our impression.” Several scientists are disputing Raoult’s claim because of his endorsement of hydroxychloroquine as a COVID-19 cure after President Trump touted the anti-malaria drug. He has been roundly criticized for insisting that his small trial of hydroxychloroquine proved its effectiveness. Still, Raoult’s team sorted out the strains from mountains of mass testing that the research hospital put in place after France confirmed the first cases of the virus in February. In the past few weeks, France has seen COVID-19 intensive care admissions and deaths grow. To try to curb the numbers, the cities of Nice, Marseille and Bordeaux have imposed new restrictions on bar hours and the size of gatherings.
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Post by Admin on Sept 25, 2020 4:56:26 GMT
A new COVID-19 mutation appears to be even more contagious, according to a study — and experts say it could be a response by the virus to defeat masks and other social-distancing efforts. Scientists in a paper published Wednesday identified a new strain of the virus, which accounted for 99.9 percent of cases during the second wave in the Houston, Texas, area, the Washington Post reported. Molecular Architecture of Early Dissemination and Massive Second Wave of the SARS-CoV-2 Virus in a Major Metropolitan Area Abstract We sequenced the genomes of 5,085 SARS-CoV-2 strains causing two COVID-19 disease waves in metropolitan Houston, Texas, an ethnically diverse region with seven million residents. The genomes were from viruses recovered in the earliest recognized phase of the pandemic in Houston, and an ongoing massive second wave of infections. The virus was originally introduced into Houston many times independently. Virtually all strains in the second wave have a Gly614 amino acid replacement in the spike protein, a polymorphism that has been linked to increased transmission and infectivity. Patients infected with the Gly614 variant strains had significantly higher virus loads in the nasopharynx on initial diagnosis. We found little evidence of a significant relationship between virus genotypes and altered virulence, stressing the linkage between disease severity, underlying medical conditions, and host genetics. Some regions of the spike protein - the primary target of global vaccine efforts - are replete with amino acid replacements, perhaps indicating the action of selection. We exploited the genomic data to generate defined single amino acid replacements in the receptor binding domain of spike protein that, importantly, produced decreased recognition by the neutralizing monoclonal antibody CR30022. Our study is the first analysis of the molecular architecture of SARS-CoV-2 in two infection waves in a major metropolitan region. The findings will help us to understand the origin, composition, and trajectory of future infection waves, and the potential effect of the host immune response and therapeutic maneuvers on SARS-CoV-2 evolution. doi: doi.org/10.1101/2020.09.22.20199125The paper, which has not been peer-reviewed, said people with the strain, known as the D614G mutation, had higher loads of virus — suggesting it is more contagious. Though the strain isn’t more deadly, researchers said it appeared to have adapted better to spread among humans. David Morens, a virologist at the National Institute of Allergy and Infectious Diseases, said the findings suggest that the virus may become more contagious and that this “may have implications for our ability to control it.” He said it’s possible that the virus had evolved to resist efforts such as hand-washing and social distancing. “Wearing masks, washing our hands, all those things are barriers to transmissibility, or contagion, but as the virus becomes more contagious, it statistically is better at getting around those barriers,” Morens told the newspaper.
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Post by Admin on Sept 25, 2020 19:28:09 GMT
When the coronavirus pandemic hit the United States this year, scientific models forecasting hundreds of thousands of deaths were met by some people with derision. The models, unfortunately, have been vindicated. And they're providing fresh warnings that a recent uptick in numbers of cases could mean the U.S. death toll could almost double in the next four months. "If we go back to March, at that time, we were saying if this thing is not handled very carefully, we could end up with 200,000 or 300,000 deaths," said a coronavirus modeler, Alessandro Vespignani, director of Northeastern University's Network Science Institute. "At that time, everyone was saying that's impossible. I think we should use that perspective now, especially when we think about the future." After beating back an initial wave of coronavirus infections, some countries in Europe find themselves in familiar territory: facing a spike in the number of new cases and weighing which restrictions could help drive the numbers down. In the U.S., after a brief dip earlier this month, the number of new cases daily is creeping up again. Since Sept. 18, the seven-day average of new Covid-19 cases in the country hasn't fallen below 40,000 a day, according to an NBC News tally. For coronavirus modelers, the writing has been on the wall. Many have watched with a mixture of horror and frustration as their projections of the pandemic's evolution, and its potential death toll, have come to fruition. Now, a widely cited model developed by the Institute for Health Metrics and Evaluation at the University of Washington suggests that the U.S. could total more than 378,000 coronavirus deaths by January. But infectious disease modeling can be a tricky science easy to criticize for its uncertainties. Experts say coronavirus models have come a long way since the early days of the pandemic, to the point where some researchers are moving away from long-term projections and focusing instead on forecasts that can more accurately predict Covid-19 trends up to six weeks. covid19.healthdata.org/united-states-of-america?view=total-deaths&tab=trend
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Post by Admin on Sept 26, 2020 19:27:38 GMT
The coronavirus is surging once again across the U.S., with cases rising in 22 states over the past week.
The big picture: There isn't one big event or sudden occurrence that explains this increase. We simply have never done a very good job containing the virus, despite losing 200,000 lives in just the past six months, and this is what that persistent failure looks like.
By the numbers: The U.S. is now averaging roughly 43,000 new cases per day, a 16% increase from a week ago.
The biggest increases are largely concentrated in the West and Midwest, though Maine and New Jersey also saw their new infections tick up over the past week.
Seven states — Arizona, Colorado, Minnesota, Montana, Texas, Utah and Wyoming — saw their daily infections rise by at least 60% over the past week.
Testing was up by almost 22% over the same period. The U.S. is now conducting about 860,000 coronavirus tests per day.
What's next: There's every reason to believe the next several months will be a particularly high-risk period.
Colder weather will cause people to move indoors, where the virus spreads more easily. People will travel and see friends and family over the holidays. Mask adherence is already only so-so. And flu season will set in at the same time.
The best way to manage that risk is to enter into it with a low number of cases.
The NIH's Anthony Fauci has said cases should ideally be below 10,000 per day heading into the fall. But we haven't been able to consistently keep them under 40,000.
The bottom line: The U.S. is racing toward a vaccine, and doctors are getting better at treating the virus. But Americans, overall, are pretty bad at doing the simple things necessary to contain the virus, save lives and make us all safer.
How it works: Each week, Axios tracks the change in new infections in each state. We use a seven-day average to minimize the effects of day-to-day discrepancies in states’ reporting.
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