Rahul Gandhi's two-day UAE visit begins

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.

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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.

Washington, May 23: President Donald Trump has labeled churches and other houses of worship as “essential" and called on governors nationwide to let them reopen this weekend even though some areas remain under coronavirus lockdown.

The president threatened Friday to “override” governors who defy him, but it was unclear what authority he has to do so.

“Governors need to do the right thing and allow these very important essential places of faith to open right now — for this weekend," Trump said at a hastily arranged press conference at the White House. Asked what authority Trump might have to supersede governors, White House press secretary Kayleigh McEnany said she wouldn't answer a theoretical question.

Trump has been pushing for the country to reopen as he tries to reverse an economic free fall playing out months before he faces reelection. White evangelical Christians have been among the president's most loyal supporters, and the White House has been careful to attend to their concerns throughout the crisis.

Following Trump's announcement, the Centers for Disease Control and Prevention released new guidelines for communities of faith on how to safely reopen, including recommendations to limit the size of gatherings and consider holding services outdoors or in large, well-ventilated areas.

Public health agencies have generally advised people to avoid gatherings of more than 10 people and encouraged Americans to remain 6 feet (1.8 meters) away from others when possible. Some parts of the country remain under some version of remain-at-home orders.

In-person religious services have been vectors for transmission of the virus. A person who attended a Mother's Day service at a church in Northern California that defied the governor's closure orders later tested positive, exposing more than 180 churchgoers. And a choir practice at a church in Washington state was labeled by the CDC as an early “superspreading" event.

But Trump on Friday stressed the importance of churches in many communities and said he was “identifying houses of worship — churches, synagogues and mosques — as essential places that provide essential services.”

“Some governors have deemed liquor stores and abortion clinics as essential” but not churches, he said. “It's not right. So I'm correcting this injustice and calling houses of worship essential." “These are places that hold our society together and keep our people united,” he added.

Dr. Deborah Birx, coordinator of the White House coronavirus task force, said faith leaders should be in touch with local health departments and can take steps to mitigate risks, including making sure those who are at high risk of severe complications remain protected.

“There's a way for us to work together to have social distancing and safety for people so we decrease the amount of exposure that anyone would have to an asymptomatic," she said.

A person familiar with the White House's thinking who spoke on condition of anonymity to discuss internal deliberations said Trump had called the news conference, which had not been on his public schedule, because he wanted to be the face of church reopenings, knowing how well it would play with his political base.

Churches around the country have filed legal challenges opposing virus closures.

In Minnesota, after Democratic Gov. Tim Walz this week declined to lift restrictions on churches, Roman Catholic and some Lutheran leaders said they would defy his ban and resume worship services. They called the restrictions unconstitutional and unfair since restaurants, malls and bars were allowed limited reopening.

Some hailed the president's move, including Kelly Shackelford, president of the conservative First Liberty Institute.

“The discrimination that has been occurring against churches and houses of worship has been shocking," he said in a statement. "Americans are going to malls and restaurants. They need to be able to go to their houses of worship.” But Rabbi Jack Moline, president of Interfaith Alliance, said it was “completely irresponsible” for Trump to call for a mass reopening of houses of worship.

“Faith is essential and community is necessary; however, neither requires endangering the people who seek to participate in them,” he said.

“The virus does not discriminate between types of gatherings, and neither should the president." Rhode Island Gov. Gina Raimondo, a Democrat, made clear that churches and other houses of worship will not resume in-person services in her state until at least next weekend and said she was skeptical Trump had the authority to impose such a requirement.

“It's reckless to force them to reopen this weekend. They're not ready,” she said. “We've got a good plan. I'm going to stick with it.” New Hampshire Gov. Chris Sununu, a Republican, said he would review the federal guidance, while maintaining a decision rests with him.

"Obviously we'd love to get to the point where we can get those open, but we'll look at the guidance documents and try to make some decisions rather quickly, depending on what it might say,” he said. “It's the governor's decision, of course.”

The CDC more than a month ago sent the Trump administration documents the agency had drafted outlining specific steps various kinds of organizations, including houses of worship, could follow as they worked to reopen safely.

But the White House dragged its feet, concerned that the recommendations were too specific and could give the impression the administration was interfering in church operations.

The guidance posted Friday contains most of the same advice as the draft guidance. It calls for the use of face coverings and recommends keeping worshippers 6 feet from one another and cutting down on singing, which can spread aerosolized drops that carry the virus.

Newsroom, May 5: Following the union government's nod, preparations are afoot to bring back Indian nationals stranded abroad from May 7 onwards.

According to sources, in the first phase from May 7- 14, the government would allow more than 60 “non-scheduled, commercial” flights to operate from about 12 countries to India to bring back 15,000 citizens. At least half of those flights will be from the Gulf region, including UAE, Qatar, Saudi Arabia, Bahrain, Kuwait and Oman, while the rest would bring passengers from the U.S., the U.K., Singapore, Malaysia, Philippines and Bangladesh.

The flights would be spread over 10 States identified as having the largest numbers to return, with Kerala, Tamil Nadu and Delhi (NCR) receiving the maximum number of flights.

A meeting held at the Ministry of Civil Aviation looked specifically at flights, mainly operated by Air India, while it awaits a final plan from countries where Indians need to be airlifted from. The first flights planned at present are from Abu Dhabi, Dubai, Riyadh and Doha, flying directly to Kozhikode and Kochi.

While the full estimate of Indians needing to return home could cross ten lakhs (a million), with more than two lakhs having registered to return from the UAE alone, officials said their return would be “prioritised and staggered”.

Flight plan for return of Indian nationals stranded abroad: