No subsidy, but record number of pilgrims will go to Haj this year: Naqvi

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, Jun 22: India's COVID-19 cases per lakh people is one of the lowest in the world despite its high population density, and the recovery rate has now reached almost 56 per cent, the Union Health Ministry said on Monday.

For every one lakh population, there are 30.04 coronavirus cases in India, while the global average is over three times at 114.67, the ministry said, referring to the WHO Situation Report 153, dated June 21.

“This low figure is thus a testimony to the graded, pre-emptive and pro-active approach the Government of India along with the states and UTs took for prevention, containment and management of COVID-19," the ministry said in a statement.

Citing the WHO Situation Report, the ministry said the US has 671.24 cases per lakh population, while Germany, Spain, Brazil and the UK have 583.88, 526.22, 489.42 and 448.86 cases per lakh population, respectively.

It said Russia has 400.82 cases per lakh people, while Italy, Canada, Iran and Turkey have 393.52, 268.98, 242.82 and 223.53, respectively.

Coming back to India, as on Monday morning, the total number of coronavirus cases stood at 4,25,282 and the death toll at 13,699, according to figures issued by the ministry.

In its update issued at 8 AM Monday, the ministry said 9,440 COVID-19 patients recovered in the last 24 hours, taking the total number of recoveries to 2,37,195, a recovery rate of 55.77 per cent.

Presently, there are 1,74,387 active cases and all are under medical supervision, it said.

"The difference between the recovered patients and the active COVID-19 cases continues to widen. Today, the number of recovered patients has crossed the number of active patients by 62,808," the ministry said.

The COVID-19 testing infrastructure is continuously being ramped up and number of government labs has been increased to 723 and the private labs to 262, adding up to a total of 985, it said.

According to the Indian Council of Medical Research, a total of 69,50,493 samples have been tested up to 21 June, 1,43,267 of them just on Sunday.

On Monday, the country added 14,821 new COVID-19 cases in a single day, pushing the tally to 4,25,282, while the death toll rose to 13,699 with 445 new fatalities reported till 8 am.

The country breached the four lakh-mark on Sunday, eight days after crossing three lakh COVID-19 cases. It has recorded 2,34,747 infections since June 1.

Monday was the 11th day in a row when the country registered over 10,000 cases.

New Delhi, Jun 20: A rare celestial event, annular solar eclipse, which is popularly known as the "ring of fire" eclipse, will be visible this Sunday in India.

It will be the first solar eclipse of this year takes place on the summer solstice, which is the longest day in the Northern Hemisphere.

While people living along the path annular eclipse passing through Anupgarh, Suratgarh, Sirsa, Jakhal, Kurukshetra, Yamunanagar, Dehradun, Tapowan and Joshimath will be able to see the annular phase, people in rest of India can witness a partial eclipse, said the Ministry of Science and Technology.

When Moon comes between the Sun and Earth, the shadow falls on the surface of the Earth. The Sun is entirely covered by the Moon for a brief period. Those places that are engulfed by the dark, dense umbral shadow of the Moon experience the total solar eclipse. In the regions that plunge into the soft diffused penumbral shadow of the Moon experience the partial eclipse.

"Annular solar eclipse is a particular case of the total solar eclipse. Like the total solar eclipse, the Moon is aligned with the Sun. However, on that day, the apparent size of the Moon happens to be a wee smaller than the Sun. Hence the Moon covers the central part of the Sun, and the rim of the Sun appear like a 'ring of fire' in the sky for a very brief moment" explains Samir Dhurde of The Inter-University Centre for Astronomy and Astrophysics, Pune.

During the solar eclipse, the apparent size of the Moon is smaller than that of the Sun by 1 per cent, the expert said.

Allying rumours that the eclipse will mark the end of coronavirus, Aniket Sule, Chairperson, Public Outreach and Education Committee of the Astronomical Society of India, said: "Solar eclipse is caused when the Moon comes in front of the Sun for a short time. As seen from Earth eclipses occur somewhere in the Earth 2 to 5 times a year. Eclipses do not impact microorganisms on Earth. Likewise there no danger in eating of stepping out during an eclipse. No mysterious rays come out of the Sun during an eclipse."