Imran Khan now marries his spiritual guide Bushra Maneka

Wuhan, Feb 23: Ninety-seven more people died in China due to coronavirus, taking the death toll to 2,442, officials said on Sunday, as a team of WHO experts visited the worst-affected Wuhan city in Hubei province.

By the end of Saturday, a total of 2,442 people had died of the disease and 76,936 confirmed cases of novel coronavirus infection had been reported in 31 provincial-level regions, China's National Health Commission (NHC) said in its daily update on Sunday.

Ninety-six deaths were reported from Hubei province and one from Guangdong province on Saturday besides 648 new confirmed cases of coronavirus infections, it said.

Hubei province, where the virus first emerged in December last, reported 630 new confirmed cases, taking the total confirmed cases in the hard-hit province to 64,084, state-run Xinhua news agency reported.

The NHC also said China's daily number of newly cured and discharged novel coronavirus patients has surpassed that of new confirmed infections for the fifth consecutive day, indicating that cases of infections are coming down.

Saturday saw 2,230 people walk out of hospital after recovery, much higher than the number of the same day's new confirmed infections, which was 648, Xinhua reported.

A total of 22,888 patients infected with the novel coronavirus had been discharged from hospital after recovery by the end of Saturday, NHC said.

Meanwhile, a team of public health experts from the World Health Organisation (WHO) visited Wuhan on Saturday to conduct a detailed probe about the virus which reportedly originated from a seafood market in the city in December last year.

The NHC said WHO experts along with their Chinese counterparts who formed a joint investigation team have held talks with the local health authority in Wuhan and visited relevant healthcare institutions.

The UN team comprises specialists from the United States, Germany, Japan, Nigeria, Russia, Singapore and South Korea, Hong-Kong based South China Morning Post reported.

The 12-member team, which arrived in China on Monday, was initially designated to visit only Beijing, Guangdong and Sichuan provinces, while the worst-affected Hubei province and its capital Wuhan were missing from the list.

However, the team was finally given permission to visit Wuhan by the Chinese government.

Besides controlling the spread of the virus, a major task for the WHO team along with their Chinese counterparts was to come up with standard medicine to cure the disease.

The NHC said on Saturday that the team had met top Chinese respiratory disease expert Zhong Nanshan in Guangdong, and visited the centre for disease control and prevention in Guangdong and the city of Shenzhen, and Sichuan.

The specialists also discussed quarantine measures, the wild animal trade and community prevention measures with their Chinese counterparts, it said.

The government suspended all the India-bound air travel from China and has declared all visas 'invalid', on Monday, due to the rapid escalation of cases of novel coronavirus outbreak which originated in Wuhan.

"Embassy and our Consulates have been receiving several queries from Chinese citizens as well as other foreign nationals, who are based out of China or visited China in the last 2 weeks, as to whether they can use their valid single/multiple entry visas to travel to India," tweeted the Embassy of India in Beijing, China.

"It is clarified that existing visas are no longer valid. Intending visitors to India should contact the Indian Embassy in Beijing ([email protected]) or the Consulates in Shanghai ([email protected]) and Guangzhou ([email protected]) to apply afresh for an Indian visa," it said.

Further, regarding the validity of visas, the embassy said, "Indian Visa Application Centres (http://blsindia-china.com) in these cities may also be contacted in this regard. Visa Section of the Embassy/Consulates of India in China can be contacted to ascertain the validity of visa before undertaking any visit to India."

"All those who are already in India (with regular or e-visa) and had traveled from China after January 15 are requested to contact the hotline number of Ministry of Health and Family Welfare of Government of India (+91-11-23978046 and email: [email protected])," the embassy said.

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.