The worldwide search for answers on COVID-19 leaves internet users vulnerable to the conspiracies that are spreading as fast as the coronavirus itself.

The World Health Organisation (WHO) has warned of an "infodemic" that undermines public trust in information at a time when transparency is essential.

Here are some of the wilder conspiracy theories surrounding COVID-19 — and why you should ignore them.

Claim: COVID-19 coronavirus was created in a Wuhan laboratory

The notorious secrecy of the Chinese government offers many possibilities for false experts.

In this case, a theory suggesting the virus had been created — accidentally or deliberately — in a laboratory at the Wuhan Disease Control and Prevention Centre has been widely rejected by outside experts.

Twenty-seven international public health researchers released a statement30418-9/fulltext) in The Lancet to "strongly condemn" the conspiracy theories suggesting that COVID-19 had "no natural origin".

These experts also hailed the diligent and effective work of "scientists, public health professionals, and medical professionals of China, in particular".

Addressing the wider 'infodemic', the researchers said: "The rapid, open and transparent exchange of data on this outbreak is now threatened by rumours and misinformation about its origins."

Claim: The Wuhan coronavirus was known about in 2015

A number of widely-shared posts on Facebook and Twitter claim the coronavirus was patented in 2015 for use as a vaccine.

If true, this would bring forward the idea that scientists were lying about the Wuhan virus being an entirely new discovery.

The theory was particularly popular among supporters of the pro-Trump QAnon movement and the anti-vaccine movement, according to Buzzfeed.

But "coronavirus" as a word refers to a whole family of viruses, including strains that caused the SARS outbreak in 2003 and MERS in 2013 as well as the current COVID-19.

An investigation by UK verification charity Fullfact found that the patent in question was for a version of avian infectious bronchitis virus (IBV) — bird flu, as it's better known.

The Pirbright Institute in Surrey, England, says none of the patented viruses it works with are those affecting humans and that the 2015 patent was to how it replicated in chickens and chicken cells.

Claim: Bill Gates is funding coronavirus

Some internet users say that viruses can be big business for research entities and pharmaceutical giants who develop vaccines — and have pointed out links between the Pirbright Institute and the Bill and Melinda Gates Foundation.

This connection has been used by some to suggest Gates personally knew about COVID-19 before it spread, or even that he was funding it.

However, the foundation's funding for Pirbright is not for work related to the coronavirus patent, and the foundation has separately pledged millions of dollars to fight COVID-19.

Claim: Millions have died from COVID-19 in China

Many believe the number of infections and deaths from COVID-19 in China is being hidden by authorities and that Beijing is covering up a true death toll of more than one million.

The WHO was asked about this at a news conference in Geneva where officials said there was no evidence of a "hidden iceberg" of cases.

Bruce Aylward, the head of the WHO mission to Wuhan, said: "I didn’t go to every single place, every corner of China, but we have a pretty good sense of what this epidemic looks like and [our] numbers are reflective of that."

Mass burning of corpses

Tabloid newspapers in Britain published meterological images that they suggested was evidence of corpse burning in Wuhan.

"Satellite images" from windy.com showed high levels of sulphur dioxide (SO2) in Wuhan and Chongqing, both cities quarantined at the epicentre of the outbreak.

The Sun newspaper ran a story suggesting Beijing was "burning the evidence" of a much bigger outbreak.

However, sulfur dioxide is naturally emitted by volcanoes and the main human source of SO2 emissions is the combustion of sulphur-containing fossils used for domestic heating, electricity generation and motor vehicles.

An investigation by Euronews found the images could not provide evidence of emissions activity due to crematoria in any case.

Super-propagators of false theories

Some of those who publish conspiracies are already celebrities on social networks. They include YouTuber Jordan Shater, whose output is shared by thousands of users.

Social networks and tech giants such as Google are trying to eliminate fake news from their publications and search engines, while Facebook announced on Wednesday it will take action against posts that appear to incite panic over COVID-19 in order to undermine public confidence or sell products.

Sometimes false theories have been propagated through the mainstream media. US Republican Senator Tom Cotton put forward the Wuhan laboratory conspiracy theory, debunked above, in an interview with Fox News.

He admitted during the interview that "we have no evidence," although he added it was something that needed to be raised "because of the duplicity and dishonesty of China from the beginning."