Gaining weight after marriage can't be ground for divorce: HC

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.

Cape Canaveral, May 31: SpaceX, the private rocket company of billionaire entrepreneur Elon Musk, launched two Americans into orbit from Florida on Saturday in a landmark mission marking the first spaceflight of NASA astronauts from U.S. soil in nine years.

A SpaceX Falcon 9 rocket lifted off from the Kennedy Space Center at 3:22 p.m. EDT (19:22 GMT), launching Doug Hurley and Bob Behnken on a 19-hour ride aboard the company’s newly designed Crew Dragon capsule bound for the International Space Station.

Just before liftoff, Hurley said, “SpaceX, we’re go for launch. Let’s light this candle,” paraphrasing the famous comment uttered on the launch pad in 1961 by Alan Shepard, the first American flown into space.

Minutes after launch, the first-stage booster rocket of the Falcon 9 separated from the upper second-stage rocket and flew itself back to Earth to descend safely onto a landing platform floating in the Atlantic.

High above the Earth, the Crew Dragon jettisoned moments later from the second-stage rocket, sending the capsule on its way to the space station.

The exhilarating spectacle of the rocket soaring flawlessly into the heavens came as a welcome triumph for a nation gripped by racially-charged civil unrest as well as ongoing fear and economic upheaval from the coronavirus pandemic.

The Falcon 9 took off from the same launch pad used by NASA’s final space shuttle flight, piloted by Hurley, in 2011. Since then, NASA astronauts have had to hitch rides into orbit aboard Russia’s Soyuz spacecraft.

“It’s incredible, the power, the technology,” said U.S. President Donald Trump, who was at Kennedy Space Center at Cape Canaveral in Florida for the launch. “That was a beautiful sight to see.”

The mission’s first launch attempt on Wednesday was called off with less than 17 minutes remaining on the countdown clock. Weather again threatened Saturday’s launch, but cleared in time to proceed with the mission.

SPACEFLIGHT MILESTONES

NASA chief Jim Bridenstine has said resuming launches of American astronauts on American-made rockets from U.S. soil is the space agency’s top priority.

“I’m breathing a sigh of relief, but I will also tell you I’m not gonna celebrate until Bob and Doug are home safely.” Bridenstine said.

For Musk, the launch represents another milestone for the reusable rockets his company pioneered to make spaceflight less costly and more frequent. And it marks the first time commercially developed space vehicles - owned and operated by a private entity rather than NASA - have carried Americans into orbit.

The last time NASA launched astronauts into space aboard a brand new vehicle was 40 years ago at the start of the space shuttle program.

Musk, the South African-born high-tech entrepreneur who made his fortune in Silicon Valley, is also chief executive of electric carmaker and battery manufacturer Tesla Inc. He founded Hawthorne, California-based SpaceX, formally known as Space Exploration Technologies, in 2002.

Hurley, 53, and Behnken, 49, NASA employees under contract to fly with SpaceX, are expected to remain at the space station for several weeks, assisting a short-handed crew aboard the orbital laboratory.

Boeing Co, producing its own launch system in competition with SpaceX, is expected to fly its CST-100 Starliner vehicle with astronauts aboard for the first time next year. NASA has awarded nearly $8 billion combined to SpaceX and Boeing for development of their rival rockets.

Trump also hailed the launch as a major advance toward the goal of eventually sending humans to Mars.

He was joined at the viewing by Musk, as well as Vice President Mike Pence, Commerce Secretary Wilbur Ross, Education Secretary Betsy DeVos, Florida congressman Matt Gaetz and Senator Rick Scott.

Earlier on Saturday, the crew bid goodbye to their families. Prior to climbing into a specially designed Tesla automobile for the ride to the launch site, Behnken told his young son, “Be good for mom. Make her life easy.”

During the drive, Behnken and Hurley passed former astronaut Garrett Reisman who held a sign saying, “Take me with you.”

Kolkata, May 15: Veteran Bengali author Debesh Roy, who was conferred the Sahitya Akademi award for his novel 'Teesta Parer Brittanto', died at a private hospital in Kolkata on Thursday, his family members said.

Roy was 84 and he is survived by his son. His wife had died earlier.

He was admitted to the hospital near his residence at Baguihati, in the eastern fringes of the city, on Wednesday after having symptoms like sodium potasium imbalance, sugar problem and breathing problem, his family members said.

He suffered a massive cardiac arrest and died at 10.50 PM.

A regular contributor to a number of Bengali dailies, he was a staunch critic of the attacks on liberals by in the country in recent times and attended protest meetings despite his failing health.

He was born in Pabna in present-day Bangladesh on December 17, 1936. He had five decades of career as a writer.

Besides Teesta Parer Britanta', he will be remembered for books like Borisaler Jogen Mondal , Manush Khun Kore Keno and Samay Asamayer Brittanto . His first book was Jajati.

His last rites will be performed tomorrow.