Mars Likely to Have Enough Oxygen to Support Life: Study

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.

Ahmedabad, Feb 29: The presence of two feral pigeons onboard a GoAir flight at the airport in Ahmedabad in Gujarat created a flutter among the amused passengers, even though the avian surprise did not lead to any untoward incident or delay in the flight.

The incident took place on Friday when the passengers were boarding the Ahmedabad-Jaipur flight.

"Two pigeons had found their way inside the flight G8 702 while the passengers were boarding," an airline statement said on Saturday.

"The crew immediately shooed away the birds. The flight took off at its scheduled time at 5 p.m.," it added.

"Do Kabootar plane ke andar "
The passengers on the Ahmedabad-Jaipur flight were surprised when two #pigeons came out of the overhead storage bin of #GoAir Aircraft, minutes before flight was to take off, flight delayed by 30 minutes. "Video Viral" via : Satish Jha pic.twitter.com/orKuZ65Can

— Joydeep Roy (@IjoydeepRoy) February 29, 2020

New Delhi, Jan 22: "Don't get into a trap. Your security is in your hands," the Border Security Force (BSF) has said issuing its social media rules for its officers and men. It has directed them not to use 42 mobile applications and show caution while using Facebook, Twitter and WhatsApp.

"Be cautious while using social media," said the BSF in a circular issued recently.

"Before using WhatsApp, Facebook, Twitter and other social media platforms, one needs to keep in mind that you are border guarding force and Central Civil Services (Conduct) Rules rule duly are applicable," it said.

It further pointed out that by commenting/writing about or forwarding unverified reports and rumours one violates laws of land.

"Several times unverified reports would be presented in way that they are absolutely true and start believing it. Seeing such post always use your commonsense and never get into the trap (sic.)," it state adding that the anti-national elements uses social media to propagate their agenda to cause unrest in India.

A picture clicked by Border Security Force personnel and posted on a social media platform remains there for always. Therefore, one should use officially approved pictures about any incident or untoward incidents related to Border Security Force, stated the circular. It pointed that unauthorised persons should not engage into taking pictures of the incidents.

It also highlighted how through social media, a few BSF personnel have fallen into trap of espionage racket carried out by enemy countries.

"Our security and respect is in our hands. Always think twice whether you are doing correct by accepting friendship requests from unknown persons, especially women and girls," it cautioned the troopers and officers.

It also highlighted that while going on leave and joining back the force, always follow the rules and regulations laid out for safety and security. "This is for your own safety," it stressed in the end.

The BSF has also issued a list of 42 mobile applications that needs to be completely avoided by serving BSF officers and jawans.

They are MI store, Weibo, Wechat, Shareit, Truecaller, UC News, UC Browser, Beautyplus, NewsDog, Viva Video - QU video Inc, Parallel Space, Apus Browser, Perfect Corp, Virus Cleaner - HI Security Lab, CM browser, MI Community, DU recorder, Vault Hide - No mobile Security, Youcam Makeup, Cachecleaner DU Apps Studio, DU battery saver, DU privacy, 360 security, DU Browser,Clean master - Cheeta Mobile, Baidu Translate, Wonder Camera - Bindu Inc, ES Ifle Explorer, Photo Wonder, QQ international , QQ music, QQ Mail, AA player, QQ News Feed, Wesync, QQ security Center, Selfie City, Mail Master, Mi Video Call -Xaomi and QQ launcher.