Phil Schiller in India to Mark Official Opening of Apple's App Accelerator in Bengaluru

Melbourne, Jul 24: Home-made cloth face masks may need a minimum of two layers, and preferably three, to prevent the dispersal of viral droplets associated with Covid-19, according to a study.

Researchers, including those from the University of New South Wales in Australia, noted that viral droplets are generated by those infected with the novel coronavirus when they cough, sneeze, or speak.

As face masks have been proven to protect healthy people from inhaling infectious droplets as well as reducing the spread from those who are already infected, several types of material have been suggested for these, but based on little or no evidence of how well they work, the scientists said.

In the current study, published in the journal Thorax, the researchers compared the effectiveness of single and double-layer cloth face coverings with a surgical face mask (Bao Thach) at reducing droplet spread.

They said the single layer covering was made from a folded piece of cotton T shirt and hair ties, and the double layer covering was made using the sew method described by the US Centers for Disease Control and Prevention (CDC).

The scientists used a tailored LED lighting system and a high-speed camera to film the dispersal of airborne droplets produced by a healthy person with no respiratory infection, during speaking, coughing, and sneezing while wearing each type of mask.

Their analysis showed that the surgical face mask was the most effective at reducing airborne droplet dispersal, although even a single layer cloth face covering reduced the droplet spread from speaking.

But the study noted that a double layer covering was better than a single layer in reducing the droplet spread from coughing and sneezing.

According to the researchers, the effectiveness of cloth face masks is dependent on the number of layers of the covering, the type of material used, design, fit as well as the frequency of washing.

Based on their observations, they said a home made cloth mask with at least two layers is preferable to a single layer mask.

"Guidelines on home-made cloth masks should stipulate multiple layers," the scientists said, adding that there is a need for more research to inform safer cloth mask design.

Paris, Apr 17: Even as virologists zero in on the virus that causes COVID-19, a very basic question remains unanswered: do those who recover from the disease have immunity?

There is no clear answer to this question, experts say, even if many have assumed that contracting the potentially deadly disease confers immunity, at least for a while.

"Being immunised means that you have developed an immune response against a virus such that you can repulse it," explained Eric Vivier, a professor of immunology in the public hospital system in Marseilles.

"Our immune systems remember, which normally prevents you from being infected by the same virus later on."

For some viral diseases such a measles, overcoming the sickness confers immunity for life.

But for RNA-based viruses such as Sars-Cov-2 -- the scientific name for the bug that causes the COVID-19 disease -- it takes about three weeks to build up a sufficient quantity of antibodies, and even then they may provide protection for only a few months, Vivier told AFP.

At least that is the theory. In reality, the new coronavirus has thrown up one surprise after another, to the point where virologists and epidemiologists are sure of very little.

"We do not have the answers to that -- it's an unknown," Michael Ryan, executive director of the World Health Organization's Emergencies Programme said in a press conference this week when asked how long a recovered COVID-19 patient would have immunity.

"We would expect that to be a reasonable period of protection, but it is very difficult to say with a new virus -- we can only extrapolate from other coronaviruses, and even that data is quite limited."

For SARS, which killed about 800 people across the world in 2002 and 2003, recovered patients remained protected "for about three years, on average," Francois Balloux director of the Genetics Institute at University College London, said.

"One can certainly get reinfected, but after how much time? We'll only know retroactively."

A recent study from China that has not gone through peer review reported on rhesus monkeys that recovered from Sars-Cov-2 and did not get reinfected when exposed once again to the virus.

"But that doesn't really reveal anything," said Pasteur Institute researcher Frederic Tangy, noting that the experiment unfolded over only a month.

Indeed,several cases from South Korea -- one of the first countries hit by the new coronavirus -- found that patients who recovered from COVID-19 later tested positive for the virus.

But there are several ways to explain that outcome, scientists cautioned.

While it is not impossible that these individuals became infected a second time, there is little evidence this is what happened.

More likely, said Balloux, is that the virus never completely disappeared in the first place and remains -- dormant and asymptomatic -- as a "chronic infection", like herpes.

As tests for live virus and antibodies have not yet been perfected, it is also possible that these patients at some point tested "false negative" when in fact they had not rid themselves of the pathogen.

"That suggests that people remain infected for a long time -- several weeks," Balloux added. "That is not ideal."

Another pre-publication study that looked at 175 recovered patients in Shanghai showed different concentrations of protective antibodies 10 to 15 days after the onset of symptoms.

"But whether that antibody response actually means immunity is a separate question," commented Maria Van Kerhove, Technical Lead of the WHO Emergencies Programme.

"That's something we really need to better understand -- what does that antibody response look like in terms of immunity."

Indeed, a host of questions remain.

"We are at the stage of asking whether someone who has overcome COVID-19 is really that protected," said Jean-Francois Delfraissy, president of France's official science advisory board.

For Tangy, an even grimmer reality cannot be excluded.

"It is possible that the antibodies that someone develops against the virus could actually increase the risk of the disease becoming worse," he said, noting that the most serious symptoms come later, after the patient had formed antibodies.

For the moment, it is also unclear whose antibodies are more potent in beating back the disease: someone who nearly died, or someone with only light symptoms or even no symptoms at all. And does age make a difference?

Faced with all these uncertainties, some experts have doubts about the wisdom of persuing a "herd immunity" strategy such that the virus -- unable to find new victims -- peters out by itself when a majority of the population is immune.

"The only real solution for now is a vaccine," Archie Clements, a professor at Curtin University in Perth Australia, told AFP.

At the same time, laboratories are developing a slew of antibody tests to see what proportion of the population in different countries and regions have been contaminated.

Such an approach has been favoured in Britain and Finland, while in Germany some experts have floated the idea of an "immunity passport" that would allow people to go back to work.

"It's too premature at this point," said Saad Omer, a professor of infectious diseases at the Yale School of Medicine.

"We should be able to get clearer data very quickly -- in a couple of months -- when there will be reliable antibody tests with sensitivity and specificity."

One concern is "false positives" caused by the tests detecting antibodies unrelated to COVID-19.

The idea of immunity passports or certificates also raises ethical questions, researchers say.

"People who absolutely need to work -- to feed their families, for example -- could try to get infected," Balloux.

New delhi, Jun 22: As consumer sentiment runs high amid growing chorus for boycotting Chinese goods in the country, the fluid market situation offers new opportunities for various smartphone makers, especially the non-Chinese ones like Samsung, Apple, Nokia, Asus and others, to realign their strategies and regain the lost market share in the face of fierce Chinese competition.

The challenge here would be not to look "opportunistic" and leverage the current explosive situation on just riding on the anti-Chinese sentiment but to offer real challenges in the form of top-end devices with solid internals at affordable price points, feel industry experts.

"The current market conditions in India are fluid and open up new opportunities for smartphone original equipment manufacturers (OEMs) to focus and leverage," Prabhu Ram, Head-Industry Intelligence Group, CyberMedia Research (CMR), told IANS.

In the first quarter (January-March) this year, Samsung's shipments were driven by its upgraded A and M series (A51, A20s, A30s, and M30s).

According to Counterpoint Research, Samsung managed to hold third position in Q1 2020 due to launches across several price tiers, especially in the affordable premium segment (S10 Lite, Note 10 Lite).

The South Korean smartphone maker last week announced a Rs 4,000 price drop on its popular Galaxy Note10 Lite smartphone that will now cost Rs 37,999 (6GB variant).

Earlier this month, Samsung launched two new smartphones, Galaxy M11 and Galaxy M01, with powerful batteries under Rs 15,000 in India.

Galaxy M11 comes in two variants. The 3GB+32GB will be priced at Rs 10,999 while the higher 4GB+64GB variant will be available for Rs 12,999.

Samsung has also launched an affordable Galaxy A21s smartphone with quad-camera system and 5,000mAh battery at a starting price of Rs 16,499.

Also read: Boycott China? OnePlus 8 Pro sold out within minutes of going on sale

On the other hand, Apple grew a strong 78 per cent YoY driven by strong shipments of iPhone 11 and multiple discounts on platforms like Flipkart and Amazon in Q1, according to Counterpoint.

Apple has also brought its cheapest yet powerful new iPhone SE that costs Rs 38,900 (64GB) in India with a special offer from HDFC Bank. The new iPhone SE is powered by the Apple-designed A13 Bionic, the fastest chip in a smartphone and features the best single-camera system ever in an iPhone.

According to Tarun Pathak, Associate Director, Counterpoint Research, consumer sentiments are running high and a section of users will look for alternatives, benefitting global and Indian brands.

"However, we do not think non-Chinese brands will run aggressive campaigns based on the situation as it might look like being opportunistic," Pathak told media.

It may actually let brands of Chinese origin try to run aggressive campaigns on their presence and scale.

"Some of these Chinese brands have been active in scaling up local value addition, creating jobs and investing in research and development," Pathak noted.

On Saturday, market leader Xiaomi said that it is "more Indian" than any other smartphone brand.

The company's India head Manu Kumar Jain said that the company's mobile phone R&D centre and product team is in India, it employs 50,000 people in the country, the entire leadership team is Indian and that the company pays its taxes in India.

Earlier, Realme India CEO Madhav Sheth who is also very active on social media said that Realme is an Indian startup.

In his latest episode of Ask Madhav' series on YouTube, Sheth said: "I can proudly say Realme is an Indian startup, which is now a global MNC (multinational corporation)".