Six feet distancing not enough to stop coronavirus transmission in light winds: Study

News Network
May 20, 2020

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.

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News Network
May 19,2020

Washington, May 19: As the scientists across the world are struggling to develop a vaccine for combating coronavirus, US drugmaker Moderna announced on Monday (local time) that the phase I trial of its Covid-19 vaccine has shown positive early results.

The company is hopeful that it's vaccine could be available to the public as early as January next year. Several firms across the world are in the race to develop a vaccine for the deadly virus which has claimed over 3 lakh lives worldwide.

CNN citing Dr. Tal Zaks, Moderna's chief medical officer reported that "if future studies go well, the company's vaccine could be available to the public as early as January".

"This is absolutely good news and news that we think many have been waiting for for quite some time," Zaks was quoted as saying.

Moderna, based in Cambridge, Massachusetts announced that the vaccine developed neutralising antibodies to the virus at levels reaching or exceeding the levels seen in people who have naturally recovered from Covid-19, reported CNN.

These will be followed by phase 2 trials and phase 3 trials, which Moderna plans to start in July.

President Donald Trump had on Friday said that that the United States will be able to deliver a few hundred million doses of COVID-19 vaccine, under 'Operation Warp Speed', by the end of this year.

"I have very recently seen early data from a clinical trial with a coronavirus vaccine and this data made me feel even more confident that we'll be able to deliver a few hundred million doses of vaccine by the end of 2020 and we will do the best we can," Trump had said at a press conference at the White House on Friday.

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News Network
April 26,2020

Apr 26: The Chinese city of Wuhan, where the global coronavirus pandemic began, now has no remaining cases in its hospitals, a health official told reporters on Sunday.

"The latest news is that by April 26, the number of new coronavirus patients in Wuhan was at zero, thanks to the joint efforts of Wuhan and medical staff from around the country," National Health Commission spokesman Mi Feng said at a briefing.

The city had reported 46,452 cases, 56% of the national total. It saw 3,869 fatalities, or 84% of China's total.

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News Network
February 9,2020

Beijing, Feb 9: After making sure everyone's face mask is on and sanitizer is to hand, the Qiao family heads out to Jingshan Park, a former royal sanctuary beside the Forbidden City in China's capital Beijing.

Snow has fallen for a second day, a rare event in the city of 21.5 million that would normally bring hundreds of thousands of people out to take photos and play. But the streets are empty and the parks are so quiet the only sound is of birds chirping.

It's not just Beijing. Shanghai, China's financial hub, and other cities in the world's most populous nation have turned into ghost towns after the government extended a holiday and asked residents not to go out because of the coronavirus.

"We know the situation of the coronavirus is severe. But the epicentre is far away, so we think it should be fine here ... It's a God-given chance to enjoy this family moment with snow and without work," said Mr Qiao, who has an 11-year-old daughter.

The epidemic has killed 722 people and infected nearly 32,000 in China as of February 8. More than three-quarters of the cases are in the central Hubei province where the virus originated - more than 1,000 km (620 miles) from Beijing.

Only a few people are brave enough to come out. A security guard at Jingshan Park said there were less than a third of the number of tourists than usual, even with the rare snowfall.

Even at one of the best spots for snapping photos of snowy Beijing just outside the Forbidden City, there's barely a crowd, while the usual tour buses and groups of people speaking different dialects are nowhere to be seen.

"Last year when it snowed, I took a few hours off work to come down here to take a picture and the crowd was several layers deep," said a man in his 30s who gave his surname as Yang. "But this year, I am not at all worried about finding a space to take a photo. The virus is keeping people indoors."

Security guards along Wangfujing street, a popular pedestrianised shopping area in downtown Beijing, said it was normally so crowded during the holiday period that it was hard to move around.

"Look at it now, there are more security guards and street cleaners than tourists!" said one of the guards.

Businesses, including shops, bars and restaurants, have been severely hit by the epidemic as the government has banned mass gatherings and even group meals in an effort to curb the spread of the coronavirus.

"You would have to wait outside for a table on a normal day," said a waitress at a restaurant with more than 50 tables. Just five were taken at the peak lunch hour.

Only a handful of the more than 100 restaurants along Beijing's famous food street, Guijie, were open, and the remaining outlets were wondering how long they can hold out.

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