Russia reports over 6,800 new COVID-19 cases as total nears 628,000

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.

Panic gripped big tech firms like Facebook and Twitter which decided to close their offices from Seattle to London as more employees tested positive for the new coronavirus.

Facebook shut its three London offices till Monday after an employee was diagnosed with COVID-19.

The social networking giant told nearly 3,000 employees in London to work from home after an employee, who is based in Singapore but visited the London offices between February 24-26, was diagnosed with the new coronavirus, Sky News reported on Friday.

"An employee based in our Singapore office who has been diagnosed with COVID-19 visited our London offices on February 24-26.

"We are therefore closing our London offices until Monday for deep cleaning and employees are working from home until then," the company said in a statement.

There have been 163 cases of coronavirus so far in the UK.

Earlier, Facebook recommended all its Bay Area employees in the US to work from home. The latest precautions come after San Francisco announced its first two coronavirus cases on Thursday.

Facebook has also shut its Seattle office until Monday after one of its contractors was confirmed to be infected with the virus. The infected contractor last visited the Facebook office on February 21. King County health officials said all Facebook sites should work from home until March 31.

Twitter shut its Seattle office for a 'deep clean' after an employee developed COVID-19 like symptoms though final result was still awaited.

"A Seattle-based employee has been advised by doctor about likely COVID-19, though still awaiting the final testing," Twitter said in a tweet on Friday.

"While the employee has not been at a Twitter office for several weeks and hasn't been in contact w/others, we're closing our Seattle office to deep clean," the company added.

According to The Seattle Times, at least 14 people have died due to COVID-19 in Washington State till date.

Amazon, Microsoft, Google and Facebook have advised their employees in Washington State to work from home.

Apple has reportedly suggested its employees at California campuses to work from home as an "extra precaution" while new coronavirus cases spread on the west coast in the US, especially Seattle area.

Apple's flagship developers' conference WWDC 2020 in June is also at the risk of getting cancelled as the Santa Clara public health department has warned against large public gatherings. The event draws nearly 5,000 developers from across the world.

The US death toll from the new coronavirus has climbed to 14, according to Johns Hopkins' tracker, with 329 cases reported across the country.

London, Apr 7: British Prime Minister Boris Johnson was moved to the intensive care unit of a London hospital after his coronavirus symptoms worsened Monday, just a day after he was admitted for what were said to be routine tests.

Johnson was admitted to St. Thomas’ Hospital late Sunday, 10 days after he was diagnosed with COVID-19, the first major world leader to be confirmed to have the virus.

Downing Street said Johnson was conscious and did not require ventilation, but he was moved into intensive care in case he needs it later, his office said in a statement.

Britain has no official post of deputy prime minister, but Foreign Secretary Dominic Raab has been designated to take over should Johnson become incapacitated.

Hours earlier, Johnson tweeted that he was in good spirits and thanked the National Health Service for taking care of him and others with the disease.

“On the advice of my doctor, I went into hospital for some routine tests as I’m still experiencing coronavirus symptoms,″ Johnson said in the tweet. “I’m in good spirits and keeping in touch with my team, as we work together to fight this virus and keep everyone safe.″

The prime minister's spokesman said earlier Monday that Johnson had spent a comfortable night and remained in charge of government after being admitted to the hospital because his cough and fever persisted.

Johnson's spokesman, James Slack, refused to say what kind of tests Johnson was undergoing. He insisted that "the PM remains in charge of the government."

“He is receiving updates in hospital and is continuing to receive a (ministerial red) box" of files and briefing papers, Slack said.

Prime Minister Narendra Modi on Monday hoped that his British counterpart Boris Johnson, admitted to a hospital for treatment of coronavirus, finds himself in perfect health soon.

"Hang in there, Prime Minister @BorisJohnson! Hope to see you out of hospital and in perfect health very soon," the prime minister wrote on Twitter.

The 55-year-old leader had been quarantined in his Downing Street residence since being diagnosed with COVID-19 on March 26. He continued to preside at daily meetings on the outbreak until Sunday. He released several video messages during his 10 days in isolation urging Britons to stay home and observe social distancing measures to help slow the spread of the virus.

Speaking earlier at the government's daily coronavirus press briefing, Raab said Johnson was being “regularly updated," but said he had not spoken to him since Saturday.

“He's in charge, but he’ll continue to take doctors’ advice on what to do next," Raab said.

Politicians from all parties wished Johnson a quick recovery. Opposition Labour Party leader Keir Starmer tweeted: “Terribly sad news. All the country’s thoughts are with the Prime Minister and his family during this incredibly difficult time."

Johnson's fiancee, Carrie Symonds, who is pregnant, is herself recovering from coronavirus symptoms.

Johnson was admitted to the hospital as a message to the nation from Queen Elizabeth II was being broadcast Sunday evening. The 93-year-old monarch urged the public to show resolve and follow advice to stay inside.

Concerns had been growing about Johnson’s welfare ever since he posted a message Friday saying that he was feeling better, though was still feverish.

The virus causes mild to moderate symptoms in most people, but for some, especially older adults and the infirm, it can cause pneumonia and lead to death.

The government said Monday that 51,608 people had been confirmed to have the coronavirus in Britain, 5,373 of whom have died.

Derek Hill, a professor of medical imaging science at University College London, said that since COVID-19 causes difficulty breathing, one test performed on people with the disease is lung imaging with ultrasound or CT scans to see how badly they might be affected.

Hill said there are various types of breathing help, depending on the person and the difficulties.

“The reasons some people get seriously ill with COVID-19 while others have minor symptoms is not yet fully understood,″ Hill said. “But doctors managing these patients report that more men than women have serious problems, and patients who are overweight or have previous health problems are at higher risk."