Suicide attack on Kabul voter registration centre kills 31

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.

Islamabad, Jul 3: The US embassy here in a statement on Friday said the Trump administration through the US Agency for International Development (USAID) “donated a shipment of 100 brand-new, state-of-the-art ventilators” to Pakistan.

The ventilators arrived in Karachi on July 2 and will be sent to hospitals across Pakistan.

“This donation delivers on President Donald Trump’s generous offer of these critically-needed supplies and supports Pakistan’s urgent response to the pandemic,” the embassy said.

Made in America, the ventilators are valued at about $3 million and reflect the latest in cutting-edge medical design and technology, it said.

They are compact, easily deployable, and will enable Pakistan to more effectively treat patients suffering from Covid-19.

The US-Pakistan health partnership to curb the spread of the novel coronavirus is helping to improve and expand laboratory testing, disease monitoring, case tracking, infection prevention and control and patient care, the embassy said.

The US has contributed nearly $27 million in new funding so far to this vital partnership that is growing every day. "We are also thankful for Pakistan's contribution of medical supplies to help fight coronavirus in the US," the embassy said in the statement.

Ambassador Paul Jones said, “The US stands with Pakistan in its fight against the coronavirus. These American-made ventilators will help Pakistani patients in the most acute need of medical care."

The announcement comes days after Pakistan said it had started producing locally designed ventilators.

Pakistan reported 78 more deaths from the coronavirus in the past 24 hours, raising virus-related fatalities to 4,551 while the total number of confirmed cases has increased to 221,896.

On Friday, the health authorities said 1,13,623 persons have recovered from the coronavirus, surpassing the number of active Covid-19 infections in the country for the first time.

New Delhi, Mar 4: The Supreme Court on Wednesday revoked the ban of cryptocurrency imposed by the Reserve Bank of India (RBI) in 2018.

Pronouncing the verdict, the three-judge bench of the apex court said the ban was 'disproportionate'.

The bench included Justice Rohinton Fali Nariman, Justice S Ravindra Bhat and Justice V Ramasubramanian.

The Internet and Mobile Association of India (IAMAI), whose members include cryptocurrency exchanges, and others had approached the top court objecting to a 2018 RBI circular directing regulated entities to not deal with cryptocurrencies.

Advocate Ashim Sood, appearing for IAMI, submitted that Reserve Bank of India lacked jurisdiction to forbid dealings in cryptocurrencies. The blanket ban was based on an erroneous understanding that it was impossible to regulate cryptocurrencies, Sood submitted.

The petitioners had argued that the RBI's circular taking cryptocurrencies out of the banking channels would deplete the ability of law enforcement agencies to regulate illegal activities in the industry.

IAMAI had claimed the move of RBI had effectively banned legitimate business activity via the virtual currencies (VCs).

The RBI on April 6, 2018, had issued the circular that barred RBI-regulated entities from "providing any service in relation to virtual currencies, including those of transfer or receipt of money in accounts relating to the purchase or sale of virtual currencies".