Rohingya's protest for justice on crackdown anniversary

The coronavirus can stay aloft for hours in tiny droplets in stagnant air, infecting people as they inhale, mounting scientific evidence suggests.

This risk is highest in crowded indoor spaces with poor ventilation, and may help explain superspreading events reported in meatpacking plants, churches and restaurants.

It’s unclear how often the virus is spread via these tiny droplets, or aerosols, compared with larger droplets that are expelled when a sick person coughs or sneezes, or transmitted through contact with contaminated surfaces, said Linsey Marr, an aerosol expert at Virginia Tech.

Follow latest updates on the Covid-19 pandemic here

Aerosols are released even when a person without symptoms exhales, talks or sings, according to Marr and more than 200 other experts, who have outlined the evidence in an open letter to the World Health Organization.

What is clear, they said, is that people should consider minimizing time indoors with people outside their families. Schools, nursing homes and businesses should consider adding powerful new air filters and ultraviolet lights that can kill airborne viruses.

What does it mean for a virus to be airborne?

For a virus to be airborne means that it can be carried through the air in a viable form. For most pathogens, this is a yes-no scenario. HIV, too delicate to survive outside the body, is not airborne. Measles is airborne, and dangerously so: It can survive in the air for up to two hours.

For the coronavirus, the definition has been more complicated. Experts agree that the virus does not travel long distances or remain viable outdoors. But evidence suggests it can traverse the length of a room and, in one set of experimental conditions, remain viable for perhaps three hours.

How are aerosols different from droplets?

Aerosols are droplets, droplets are aerosols — they do not differ except in size. Scientists sometimes refer to droplets fewer than 5 microns in diameter as aerosols. (By comparison, a red blood cell is about 5 microns in diameter; a human hair is about 50 microns wide.)

From the start of the pandemic, the WHO and other public health organizations have focused on the virus’s ability to spread through large droplets that are expelled when a symptomatic person coughs or sneezes.

These droplets are heavy, relatively speaking, and fall quickly to the floor or onto a surface that others might touch. This is why public health agencies have recommended maintaining a distance of at least 6 feet from others, and frequent hand washing.

But some experts have said for months that infected people also are releasing aerosols when they cough and sneeze. More important, they expel aerosols even when they breathe, talk or sing, especially with some exertion.

Scientists know now that people can spread the virus even in the absence of symptoms — without coughing or sneezing — and aerosols might explain that phenomenon.

Because aerosols are smaller, they contain much less virus than droplets do. But because they are lighter, they can linger in the air for hours, especially in the absence of fresh air. In a crowded indoor space, a single infected person can release enough aerosolized virus over time to infect many people, perhaps seeding a superspreader event.

For droplets to be responsible for that kind of spread, a single person would have to be within a few feet of all the other people, or to have contaminated an object that everyone else touched. All that seems unlikely to many experts: “I have to do too many mental gymnastics to explain those other routes of transmission compared to aerosol transmission, which is much simpler,” Marr said.

Can I stop worrying about physical distancing and washing my hands?

Physical distancing is still very important. The closer you are to an infected person, the more aerosols and droplets you may be exposed to. Washing your hands often is still a good idea.

What’s new is that those two things may not be enough. “We should be placing as much emphasis on masks and ventilation as we do with hand washing,” Marr said. “As far as we can tell, this is equally important, if not more important.”

Should I begin wearing a hospital-grade mask indoors? And how long is too long to stay indoors?

Health care workers may all need to wear N95 masks, which filter out most aerosols. At the moment, they are advised to do so only when engaged in certain medical procedures that are thought to produce aerosols.

For the rest of us, cloth face masks will still greatly reduce risk, as long as most people wear them. At home, when you’re with your own family or with roommates you know to be careful, masks are still not necessary. But it is a good idea to wear them in other indoor spaces, experts said.

As for how long is safe, that is frustratingly tough to answer. A lot depends on whether the room is too crowded to allow for a safe distance from others and whether there is fresh air circulating through the room.

What does airborne transmission mean for reopening schools and colleges?

This is a matter of intense debate. Many schools are poorly ventilated and are too poorly funded to invest in new filtration systems. “There is a huge vulnerability to infection transmission via aerosols in schools,” said Don Milton, an aerosol expert at the University of Maryland.

Most children younger than 12 seem to have only mild symptoms, if any, so elementary schools may get by. “So far, we don’t have evidence that elementary schools will be a problem, but the upper grades, I think, would be more likely to be a problem,” Milton said.

College dorms and classrooms are also cause for concern.

Milton said the government should think of long-term solutions for these problems. Having public schools closed “clogs up the whole economy, and it’s a major vulnerability,” he said.

“Until we understand how this is part of our national defense, and fund it appropriately, we’re going to remain extremely vulnerable to these kinds of biological threats.”

What are some things I can do to minimize the risks?

Do as much as you can outdoors. Despite the many photos of people at beaches, even a somewhat crowded beach, especially on a breezy day, is likely to be safer than a pub or an indoor restaurant with recycled air.

But even outdoors, wear a mask if you are likely to be close to others for an extended period.

When indoors, one simple thing people can do is to “open their windows and doors whenever possible,” Marr said. You can also upgrade the filters in your home air-conditioning systems, or adjust the settings to use more outdoor air rather than recirculated air.

Public buildings and businesses may want to invest in air purifiers and ultraviolet lights that can kill the virus. Despite their reputation, elevators may not be a big risk, Milton said, compared with public bathrooms or offices with stagnant air where you may spend a long time.

If none of those things are possible, try to minimize the time you spend in an indoor space, especially without a mask. The longer you spend inside, the greater the dose of virus you might inhale.

Davos, Jan 24: Pakistan Prime Minister Imran Khan claimed that he met with a “brick wall” when he approached Indian Prime Minister Narendra Modi with a peace proposal, soon after assuming office.

In an interview to Foreign Policy magazine on the sidelines of WEF 2020 here, Khan also said he told Modi that Pakistan will act firmly if it was given evidence of any involvement in the Pulwama terror attack, but India instead “bombed” Pakistan.

Tensions have escalated between the two countries, following India withdrawing the special status of Jammu and Kashmir in August 2019. Even since, Khan has been trying to seek global intervention to de-escalate the tensions between the two countries.

On Thursday, India's External Affairs Ministry spokesperson Raveesh Kumar categorically ruled out any third party role on the Kashmir issue, asserting that any issue between the two countries should be resolved bilaterally.

In the interview, Khan said that he is a firm believer that military means are not a solution to ending conflicts. “After assuming office, I immediately reached out to Prime Minister Modi. I was amazed by the reaction I got, which was quite weird.

The subcontinent hosts the greatest number of poor people in the world, and the best way to fight poverty is to have a trading relationship between the two countries rather than spending money on arms. This is what I said to the Indian Prime Minister. But I was met by brick wall,” Khan said.

Khan took charge as Prime Minister in August 2018. Referring to the suicide attack in Pulwama, Khan said he immediately told Modi ,“if you can give us any actionable intelligence (that Pakistanis were involved), we will act on it. But rather than do so, they bombed us.”

Noting that the both countries are not close to conflict right now, Khan said that it is important that the UN and the US act.

When asked about US President Donald Trump’s close relationship with Modi, Khan said the relationship is understandable because India is a huge market. “My concern is not about the US-India relationship. My concern is the direction in which India is going,” Khan said.

Khan also sought to compare the events in India to what happened in Nazi Germany.

“Between 1930 and 1934, Germany went from a liberal democracy to a fascist, totalitarian, racist state. If you look at what is happening in India under the BJP in the last five years, look where it's heading, you'll see the danger. And you're talking about a huge country of 1.3 billion people that is nuclear-armed,” he 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.