Hardik Pandya Slams Michael Holding's "Nowhere Near Kapil Dev" Jibe After Routing England

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 15: A total of 1,15,519 samples of COVID-19 have been tested in the last 24 hours taking the total samples tested to 57,74,133 in the country, the Indian Council of Medical Research (ICMR) said.

"Total sample tested 57,74,133 and samples tested in the last 24 hours is 1,15,519," said ICMR.

With an increase of 11,502 cases in the past 24 hours, the COVID-19 count in India reached 3,32,424 on Monday, according to the Union Health and Family Welfare Ministry.

The COVID-19 count includes 1,53,106 active cases while 1,69,798 patients have been cured and discharged or migrated so far, and the toll due to COVID-19 has now reached 9,520.

United Nations, May 7: An average of 80,000 COVID-19 cases were reported each day in April to the World Health Organization, the top UN health agency has said, noting that South Asian nations like India and Bangladesh are seeing a spike in the infections while the numbers are declining in regions such as Western Europe.

WHO Director-General Tedros Adhanom Ghebreyesus said on Wednesday that countries must also be able to manage any risk of the disease being imported into their territories, and communities should be fully educated to adjust to what will be a "new norm".

He said as the countries press forward in the common fight against COVID-19, they should also lay the groundwork for resilient health systems globally.

"More than 3.5 million cases of COVID-19 and almost 250,000 deaths have now been reported to the WHO. Since the beginning of April, an average of around 80,000 new cases have been reported to the WHO every day," Ghebreyesus said in Geneva yesterday.

Asserting that the virus cases were not just numbers, he said: "every single case is a mother, a father, a son, a daughter, a brother, sister or friend".

He said while the numbers are declining in Western Europe, more cases are being reported every day from Eastern Europe, Africa, South-East Asia, the Eastern Mediterranean and the Americas. Even within regions and within countries, there are divergent trends, the agency added.

While some countries are reporting an increase in COVID-19 cases over time, many have seen caseloads rise because they have ramped up testing, the WHO official said.

"We've also seen in Europe and Western Europe a fundamental decrease in the number of cases, but we have seen an associated increase in the number of cases reported in places like the Russian Federation. Southeast, the Western Pacific areas are relatively on the downward trend like Korea and others, but then we do see in South Asia, in places like Bangladesh, in India, some trends towards increase.

"So it's very difficult to say that any particular region is improving or (not improving). There are individual countries within each region that are having difficulties getting on top of this disease and I am particularly concerned about those countries that have (an) ongoing humanitarian crisis," WHO's Executive Director Michael Ryan said.

The death toll due to COVID-19 in India rose to 1,783 while the number of cases climbed to 52,952 on Thursday, registering an increase of 89 deaths and 3,561 cases in the last 24 hours, the Union Health Ministry said.

The number of active COVID-19 cases stood at 35,902 while 15,266 people have recovered, it said.

Noting that while seeing an increase in the number of cases is not good in terms of transmission, WHO's Emerging Diseases and Zoonoses Unit head Maria Van Kerkhove said: "but I don't want to equate that with something (being) wrong".

"I want to equate that with countries are working very hard to increase their ability to find the virus, to find people with the virus, to have testing in place to identify who has COVID-19, and putting into place what they need to do to care for those patients," Kerkhove said.

With more countries considering easing restrictions implemented to curb the spread of the coronavirus, the WHO has again reminded the authorities of the need to maintain vigilance.

"The risk of returning to lockdown remains very real if countries do not manage the transition extremely carefully, and in a phased approach," Ghebreyesus said.

He urged countries to consider the UN agency's six criteria for lifting stay-at-home measures.

That advice includes ensuring surveillance is strong, cases are declining and transmission is controlled. Health systems also must be able to detect, isolate, test and treat cases, and to trace all contacts.

Additionally, the risk of outbreak in settings such as health facilities and nursing homes needs to be minimised, while schools, workplaces and other public locations should have preventive measures in place.

"The COVID-19 pandemic will eventually recede, but there can be no going back to business as usual. We cannot continue to rush to fund panic but let preparedness go by the wayside," he said.

He said the crisis has highlighted the importance of strong national health systems as the foundation of global health security: not only against pandemics but also against the multitude of health threats that people across the world face every day.

"If we learn anything from COVID-19, it must be that investing in health now will save lives later," Ghebreyesus said.

While the world currently spends around USD 7.5 trillion on health annually, the WHO believes the best investments are in promoting health and preventing disease.

"Prevention is not only better than cure, it's cheaper, and the smartest thing to do," he said.

The deadly coronavirus, which originated from the Chinese city of Wuhan in December last year, has infected over 3.7 million people and killed 263,831 people globally, according to a tally by Johns Hopkins University.