Saudi woman held at Bangkok airport pleads for asylum

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.

New Delhi, Jan 4: "Sovereign, socialist, secular, democratic republic" is how India is referred to in the preamble of the Constitution. However, J Nandakumar, a key RSS leader and All India Convenor Prajna Pravah, a Sangh offshoot, wants India to reconsider the inclusion of the word "secular", claiming secularism is a "western, Semitic concept".

In an exclusive interview to news agency, Nandakumar said: "Secularism is a western, Semitic concept. It came into existence in the West. It was actually against Papal dominance."

He argued that India does not need a secular ethos as the nation has moved "way beyond secularism" since it believes in universal acceptance as against the western concept of tolerance.

The RSS functionary on Thursday released a book here named "Hindutva in the changing times". The book launch event was also attended by senior RSS functionary Krishna Gopal.

Nandakumar, who has attacked the Mamata Banerjee government in his book for alleged "Islamisation of West Bengal", told IANS: "We have to see whether we need to put up a board of being secular, or that whether we should prove this through our behaviour, actions and roles."

It is for society to take a call on this, rather than by any political class, on whether the preamble to the Indian Constitution should continue to have the word "secular" in it or not, he added.

In between signing his books and obliging wannabe Hindutva cadres with selfies, Nandakumar said that the very existence of the word "secular" in the preamble was not necessary and how the constitution founders too were against it.

"Baba Saheb Ambedkar, Ladi Krishnaswamy Aiyaar -- all debated against it and said it (secular) wasn't necessary to be included in the preamble. That time it was demanded, discussed and decided not to include it," he said.

Ambedkar's opinion was, however, disregarded when Indira Gandhi "bulldozed" the word "secular", in 1976, said the head of the Prajna Pravah, an umbrella body of several right-wing think-tanks

As Nandakumar prepared to return to his base in Kerala, where, he emphasises, the RSS has its work cut out in the "fight against the Kunnor model", he said that the inclusion of "secular" was done with the intent to damage the concept of Hindutva.

"It was to demolish, destroy the overarching principle of Hindutva that binds us together", he said.

Asked whether the Sangh would pressurise the BJP, which has 303 seats in the Lok Sabha, to omit "secular" from the Constitution preamble, Nandakumar smilingly refused to reply.

New Delhi, Jul 8: India has reported a spike of 22,752 COVID-19 cases in the last 24 hours, taking the country's coronavirus tally to 7,42,417 on Wednesday, informed the Union Ministry of Health and Family Welfare.

Out of the total cases reported, 4,56,830 patients have been cured/discharged from the disease while one patient has been migrated, the Health Ministry informed.

It added that there are 2,64,944 active cases in the country.

482 deaths reported in the last 24 hours due to COVID-19 in the country, taking India's death toll to 20,642.

According to the Union Health Ministry, Maharashtra continues to be the worst affected state reporting 2,17,121 coronavirus cases and 9,250 fatalities.

Tamil Nadu -- the second worst-affected state from COVID-19 -- has a total of 1,18,594 cases and 1,636 deaths due to coronavirus.

While Delhi has a total of 1,02,831 COVID-19 cases including 3,165 deaths.

The Indian Council of Medical Research on Wednesday informed that a total of 1,04,73,771 samples tested for COVID-19 up to July 7. Of these, 2,62,679 samples were tested on Tuesday.