Road accidents are the biggest killers of teenagers in the world: WHO

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.

Facebook will introduce a new notification screen on its platform that will warn users if the article they are about to share is over 90 days old, the company announced on Thursday.

“We’re starting to globally roll out a notification screen that will let people know when news articles they are about to share are more than 90 days old,” Facebook wrote in a blog post.

The social media platform had previously introduced a context button in 2018 that provides information about the sources of articles in the News Feed. Building upon that, the new feature will inform users about the timeliness of the article.

“To ensure people have the context they need to make informed decisions about what to share on Facebook, the notification screen will appear when people click the share button on articles older than 90 days, but will allow people to continue sharing if they decide an article is still relevant,” Facebook said.

The social media giant stated that timeliness is important in understanding the context of an article and curbing the spread of misinformation on the platform.

“News publishers, in particular, have expressed concerns about older stories being shared on social media as current news, which can misconstrue the state of current events. Some news publishers have already taken steps to address this on their own websites by prominently labelling older articles to prevent outdated news from being used in misleading ways,” Facebook added.

Apart from this, the platform will also be testing a similar notification screen for information related to the global Covid-19 pandemic. The notification screen will provide information about the source of the link shared in a post if the link is related to information on Covid-19. It will also direct people to its previously introduced Covid-19 information centre for “authoritative” health information, it said.

Kochi, May 22: During the nationwide COVID-19 lockdown, Kerala recorded the highest number of cyber attacks followed by Punjab and Tamil Nadu, a study by anti-virus software firm K7 Computing said on Thursday.

In a statement issued in Chennai, the company said its K7 Computing's Cyber Threat Report, a comprehensive analysis of cyber attacks during the lockdown has found that Kerala recorded the highest number of cyber attacks during this period. The report analyses various cyber attacks within India during the pandemic and reveals that threat actors targeted the state with COVID-themed attacks aimed at exploiting user trust.

In Kerala, regions like Kottayam, Kannur, Kollam, and Kochi saw the highest hits with 462, 374, 236, and 147 attacks respectively, while the state as a whole saw around 2,000 attacks during the period - the highest thus far in the country.

This was followed by Punjab with 207 attacks and Tamil Nadu with 184 attacks, the company said.

The sudden surge in the frequency of attacks witnessed from February 2020 to mid-April 2020 indicates that scamsters across the world were exploiting the widespread panic around coronavirus at both the individual and corporate level.

These attacks aimed to compromise computers and mobile devices to gain access to users' confidential data, banking details, and cryptocurrency accounts.

The key threats seen during this period ranged from phishing attacks to rogue apps disguised as COVID-19 information apps that targeted users' sensitive data. Phishing attacks were noticed more in Tier-II and Tier-III cities while the metros fared better. Smaller cities saw over 250 attacks being blocked per 10,000 users.

Users from Ghaziabad and Lucknow seem to have faced almost 6 and 4 times the number of attacks as Bengaluru users.

According to the statement, a majority of the recorded attacks were phishing attacks with sophisticated campaigns that could easily snare even the most educated users. These attacks were aimed at heightening users' fears and creating a sense of urgency to take action.

K7 Labs noticed phishing attacks where scamsters posed as representatives of the United States Department of Treasury, the World Health Organization (WHO), and the Centres for Disease Control and Prevention (CDC), the company said.

Users were encouraged to visit links that would automatically download malware on the host computer such as the Agent Tesla keylogger or Lokibot information-stealing malware, infamous banking Trojans such as Trickbot or Zeus Sphinx, and even disastrous ransomware.

Other attacks included infected COVID-19 Android apps like CoronaSafetyMask that scam users with promises of masks for an upfront payment; the spyware app Project Spy; and seemingly genuine apps that are infected with dangerous malware like banking Trojans such as Ginp, Anubis and Cerberus.

"Covid-19 has created an ideal situation for various threat actors to target individuals and enterprises alike. The panic caused by the stringent lockdown measures and rapid spread of this virus has left many people looking for more information on the situation," J. Kesavardhanan, Founder and CEO of K7 Computing was quoted as saying in the statement.

"Threat actors exploit this fear to their advantage and scam users into downloading malicious software and divulging sensitive information like banking codes. The need to be cyber cautious has never been greater. This is more so in the case of corporates who have adopted a work from home policy hurriedly without adequate cyber hygiene. We have seen an increase in attacks on enterprises and SME employees as well," he added.

Such attacks are expected to continue till normalcy returns. Social engineering attacks targeted at winning users' trust will gain momentum.

Healthcare institutions, well-known government offices, and international organisations will continue to be a prime target throughout the pandemic, the statement said.