South Korea's top court formally ousts President Park Geun-hye

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.

Jun 9: The World Health Organization says it still believes the spread of the coronavirus from people without symptoms is “rare,” despite warnings from numerous experts worldwide that such transmission is more frequent and likely explains why the pandemic has been so hard to contain.

Maria Van Kerkhove, WHO''s technical lead on COVID-19 said at a press briefing on Monday that many countries are reporting cases of spread from people who are asymptomatic, or those with no clinical symptoms.

But when questioned in more detail about these cases, Van Kerkhove said many of them turn out to have mild disease, or unusual symptoms.

Although health officials in countries including Britain, the U.S. and elsewhere have warned that COVID-19 is spreading from people without symptoms, WHO has maintained that this type of spread is not a driver of the pandemic and is probably accounts for about 6 per cent of spread, at most.

Numerous studies have suggested that the virus is spreading from people without symptoms, but many of those are either anecdotal reports or based on modeling.

Van Kerkhove said that based on data from countries, when people with no symptoms of COVID-19 are tracked over a long period to see if they spread the disease, there are very few cases of spread.

“We are constantly looking at this data and we''re trying to get more information from countries to truly answer this question,” she said. “It still appears to be rare that asymptomatic individuals actually transmit onward.”

Seoul, Apr 15: Wearing masks and gloves, South Korean voters cast their ballots on Wednesday to elect 300 parliamentary lawmakers amid the coronavirus outbreak.

Voting kicked off at 6 am (local time) and was to run until 6 pm (local time) at 14,330 polling stations across the country, according to the National Election Commission (NEC). The number of eligible voters is 44 million, according to Yonhap news agency.

The once-in-four-years legislative election is widely seen as a referendum on President Moon Jae-in, whose five-year term will end in mid-2022, as well as a test of the country's fight against COVID-19 under the leadership of Moon, The Strait Times reported.

South Korea has received international praise for its massive testing capability and other innovative measures, such as drive-through testing and high-tech contact tracing.

Experts, therefore, expect the ruling Democratic Party (DP) to extend its lead in Parliament, given that the government's handling of the virus outbreak is viewed positively both at home and abroad, as per The Strait Times.

At least 10,564 people in the country have been infected by coronavirus, which has claimed 222 lives. About 2,800 patients are undergoing treatment.

The number of new cases has fallen from a high of 813 on February 29 to below 50 for six days in a row as an intensive social distancing campaign that started on March 21 remained in place.

Several surveys cited by the newspaper also showed that voters consider the pandemic as the biggest factor in their decision. A recent poll showed that 72.6 per cent of respondents rated the government's response to the outbreak as positive.

The NEC has said that public safety at polling stations will be a priority to prevent any possible spread of the virus.

All 14,330 polling stations and 251 counting stations will be disinfected on polling day, the NEC was quoted.

Voters will undergo temperature screening and those registering temperatures of 37.5 degrees Celsius or higher or display respiratory symptoms will have to exercise their franchise at a separate booth.

Tuesday was the last of 13 days of campaigning, which saw most candidates reducing their ground activities and face-to-face encounters with voters. Instead, the candidates boosted their online presence with videos and social media engagements in a bid to win votes, according to The Strait Times.

In addition, the government has also decided to temporarily lift quarantine rules to permit self-isolators to vote in the elections. Some 50,000 people in self-isolation who have no symptoms and expressed a willingness to vote will be allowed to cast ballots after the regular voting ends in the evening.