BBC teams are fact-checking some of the most popular fake and misleading coronavirus stories on social media. Jack Goodman brings together what's been debunked this week by BBC Monitoring, Trending and Reality Check.

False claims about the BCG vaccine

WhatsApp messages claiming the BCG vaccine prevents coronavirus infection are inaccurate.

The Bacille Calmette-Guérin jab has been given to children around the world to fight off tuberculosis, and was widespread in secondary schools in the UK until 2005.

It's still given in the UK when a child or adult might be at risk of coming into contact with tuberculosis.

It's still common in many countries, such as Syria, where rumours are spreading that people shouldn't worry about coronavirus if they've had the BCG jab because it gives them immunity.

A WhatsApp message in Arabic says that if you have the circular scar from the jab on your arm, you could be "75% protected" against Covid-19.

However, the World Health Organization says there is no evidence that the BCG protects people from Covid-19 infection.

The health body says two clinical trials are under way involving BCG, and when completed, their findings will be evaluated by the WHO.

Despite the lack of medical evidence, global search for the term "BCG" has spiked, according to Google.

The WHO is concerned that increased demand for the vaccine means there'll be less of it available to inoculate children against tuberculosis.

Similar fears have also been voiced by suppliers in Japan, reporting a surge in demand for the BCG vaccine.

Iran's dodgy detector

The head of Iran's Revolutionary Guard Corps (IRGC) unveiled a hand-held device this week which he claimed could identify people infected with coronavirus - and even contaminated surfaces - up to a distance of 100m and within five seconds.

The Physics Society of Iran described the announcement as "pseudoscience", "unbelievable" and on a par with "sci-fi tales".

The device bears an uncanny resemblance to fake bomb detector tools sold by British fraudsters more than a decade ago, all of which claimed to use the same "electrostatic magnetic ion attraction".

So, Iran's Revolutionary Guards unvelied a "magnetic" coronavirus detector today, which its chief Maj-Gen Hossein Salami claimed could detect an infected individual or contaminated surface in 5 secs within a diametre of 100m. But there's a HUGE problem...pic.twitter.com/hTKrVK8oIN

— Shayan Sardarizadeh (@Shayan86) April 15, 2020

The bogus bomb detectors were in fact empty cases with an aerial which swings according to the user's unconscious hand movements. They ended up in conflict zones and were used by a number of governments around the world.

This latest device has an almost identical case and antenna.

Even the packaging, which can be seen in a clip of it being unveiled on Iranian state TV, looks similar.

The virus wasn't created in a lab

A video published by the Epoch Times, that contains claims that the coronavirus was created in a laboratory, has been marked false on Facebook where it has been watched almost 70 million times.

The opening feels like a slick and dramatic Netflix documentary - there's a flash and crack of a lightning bolt followed by ominous music.

The hour-long video includes a theory about a lab in Wuhan creating the virus and leaking it, due to poor security.

The BBC's science editor, Paul Rincon, says "there's currently no evidence that any research institute in Wuhan was the source of Sars-CoV-2" (which causes Covid-19).

Scientific analysis of the evidence shows the virus came from animals, and was not man-made.

A peer-reviewed study in March found no evidence the coronavirus had been engineered, stating that "it is improbable that SARS-CoV-2 emerged through laboratory manipulation."

The video also refers to a study from Indian researchers that claimed to find four new sequences had been inserted into the new coronavirus, which were also present in HIV, to suggest the virus is man-made.

But that paper, never peer-reviewed, was withdrawn by its authors. And the genetic information that had matched is common in many other organisms.

"Those sequences are so short that they match with many different organisms, not just HIV. It doesn't mean they're related," says Dr Jeremy Rossman, a virologist at the University of Kent.

Epoch Times, based in New York City, was started by Chinese-Americans affiliated with a religious group called Falun Gong.

The site spent heavily on pro-Donald Trump Facebook adverts last year, reported NBC News.

But in August Facebook banned it from taking out more ads for violating its policies.



More Bill Gates rumours

This week Bill Gates' criticism of Donald Trump's decision to halt funding for the WHO sparked a new wave of misinformation and speculation about Mr Gates.

It followed familiar themes, such as criticising Mr Gates' support for vaccines.

Multiple posts resurfaced on Facebook claiming that a research institute funded by the Bill and Melinda Gates Foundation owns the patent on the coronavirus causing the current pandemic.

These claims are all totally unsubstantiated. The suggestion that Covid-19 is a human creation sponsored by Bill Gates is false.

The Covid pandemic is not fake

The coronavirus pandemic is "fake" and "truly a farce" is the claim of a holistic doctor interviewed by Canal Monteria, a Colombian news channel. The video went up last month but has now been viewed 18 million times and is still being shared on Facebook, which is why we're addressing it now.

The claim is clearly false - coronavirus does exist.

The man in the video goes unchallenged and says that present theories on viruses are all wrong, and recommends a video on YouTube that denies the existence of HIV to prove his point.

He doesn't at any point explain why people are getting ill.