As conspiracy theories go, the origins of the COVID-19 pandemic offered all the right ingredients. Scientists think the virus jumped from wild animals into humans, likely in late 2019 in the bustling Huanan Seafood Wholesale Market of Wuhan, central China.

But it just so happens that a half-hour drive from that market, across the Yangtze River, is China’s highest-security biosafety laboratory. At the Wuhan Institute of Virology, hazard suits are de rigueur for scientists studying some of the world’s most dangerous diseases.

Within days of news that a new deadly coronavirus had been identified in humans, unfounded claims that it was really a bioweapon or escaped experiment from this Wuhan lab were spreading nearly as fast as the virus itself.

Now the world is in the grip of a new pandemic, this time in the golden age of social media, and conspiracy theorists are in their element. But why do pandemics breed conspiracy theories? What are scientists saying? And is there any right way to argue with a conspiracy theorist?

What are the theories about COVID-19?

Some theories claim that COVID-19 is a population-control scheme or a top-secret spy operation gone wrong. Others question whether it exists at all or point to similar (but unrelated) patents for coronavirus vaccines as a sign it's all a cash grab by big pharmaceutical companies. More than one breathless Youtuber has blamed Wuhan’s recent rollout of 5G Wi-Fi.

Politicians from the US, Iran, South America and even China have ignored the findings of their own scientists and seized on fringe theories to weaponise the crisis against their rivals. Kremlin-friendly sites and Chinese blogs hiss COVID-19 was cooked up by the CIA. The Trump White House, meanwhile, floats the theory that it's really a plot to bring down the US President.

This story of a virus built in a lab is one of the most popular out there, but perhaps the most easily debunked. The new strain's genome has now been studied by thousands of scientists around the world. They've already found a close match in a bat virus discovered in 2013, and say this new strain can only have evolved in nature – it's too good to be a cut-and-paste job, and it would make a pretty poor weapon because it is highly contagious (and so uncontrollable) but not as deadly as other pathogens.

They don’t know exactly where or how it finally made the jump from animals into humans, but they think it happened around late 2019 in Wuhan - researchers put the time of the spillover into humans between October and December last year. While 'patient zero' or the first human case has yet to be confirmed, the earliest record in China of the mysterious new form of pneumonia is reportedly November 17. Many of those early cases have also been traced back to the seafood market in Wuhan, where vendors were known to sell wildlife, and investigators found environmental samples of the virus.

Such wet markets are notorious breeding grounds for disease as stressed animals from all corners of the world are caged close together, trading unfamiliar diseases, and then handled and butchered by humans. It happened that way with SARS, the first deadly coronavirus outbreak of the modern era, and then again with the second, MERS, this time along camel trade routes and slaughterhouses in the Middle East.

So why does the bioweapon rumour persist? Some of the trouble started with a draft paper, which was not peer reviewed, claiming to find traces of HIV artificially inserted into the new virus's genetic code. The work was quickly withdrawn by its authors after it was debunked for using incorrect data but not before it was seized upon by blogs and right-wing pundits as "proof" of manipulation, eventually finding its way into a US senator's talking points and Fox News bulletins.

President Donald Trump has said he is confident the Wuhan lab was connected to the outbreak, using public White House briefings on the coronavirus crisis to amplify the theory, but has not presented any evidence. US intelligence agencies have already concluded the virus was "not man-made or genetically modified" and have said they are still looking into speculation the virus may have been accidentally released by the lab.

Back at that lab, scientists were on the frontline of the outbreak in a sense – theirs was the only facility in China able to safely handle the new pathogen. The institute is an offshoot of the state-owned Chinese Academy of the Sciences, and part of a collaboration with France. But it wasn’t built for the development of "biological warfare", as has been reported in some corners of the media, and virologists say it's far from top-secret – international collaboration is common.

Forced to issue a statement early into the outbreak denying rumours a student from the lab was the so-called Patient X, or first case, researchers said they had been "racing against time", many of them recalled early from their holidays, to help identify and tackle the virus. Still, suspicion lingered – viral leaks from labs are not without precedent. While its researchers had been trained to handle dangerous pathogens as part of a long partnership with the Galveston lab in the US, theWashington Post reported that American officials raised concerns about biosecurity at the Wuhan lab back in 2018. The centre had been studying coronaviruses, as are many such institutes around the world.

In fact, one of the team, China’s "bat woman", respected virologist Shi Zhengli, had been warning another SARS-like coronavirus would jump from bats into humans sooner or later. When the call did come, one evening in early December, she reportedly checked all the lab's samples, just in case something had been mishandled. It hadn’t, she said. This virus was new (scientists say it has not been reported before), but analysis found the strain was also 96 per cent similar to one that Shi herself had already identified seven years earlier, in a bat down in China’s south.

A 96% match to a known virus might sound suspiciously close. But in virus years scientists studying its genome say it likely split off from that bat strain about 50 years ago and kept evolving on its own. Shi's work cataloguing wild viruses may have now given the world a headstart on ending this pandemic.

Australian intelligence agencies have also looked into the idea of an accidental lab release as well as the notion of a deliberate one - and have turned up no evidence. The Prime Minister has already privately dismissed the lab scenario, as he calls for a global crackdown on wet markets known to pose health risks. Senior sources within the intelligence community say there is growing concern about such speculation being splashed across newspapers and mentioned by politicians when there is zero evidence to support it - a supposedly explosive US dossier supporting the theory trumpeted by the Trump administration has been dismissed as mostly full of news reports - Australian sources who had seen the document under the Five Eyes sharing agreement said it contained no material from intelligence gathering.

While Australia and reportedly other Five Eyes agencies such as Britain believe China has not been transparent about the initial outbreak, likely concealing early cases, a wet market and, more broadly, the wildlife trade is still considered the most likely cause. "We can't rule [a lab leak] out, we can't rule out a lot of things," one Australian intelligence source said. "It's hard to prove a negative".

Still accusations against the Wuhan lab continue to cause headaches for its team – a known US conspiracy theorist and lawyer has filed a multi-trillion-dollar lawsuit against Shi, the institute and the Chinese government over the release of a “bioweapon”. After a number of the researchers were targeted online and their personal details released, Shi herself was forced to make a statement swearing on her life the virus had not come from the lab. But in late April, more stories surfaced - News Corp’s Australian media reported Shi and a colleague at the institute had previously studied live bats in Australia in research jointly funded by the Australian and Chinese governments. At the CSIRO where the research took place, scientists defended their safety record and said the work was critical to preventing pandemics.

Why are COVID-19 conspiracy theories spreading so fast?

But is it really so crazy to believe a story like that? Colin Klein, an Associate Professor of Philosophy at the Australian National University, says when "things are changing rapidly [and] it’s not actually unreasonable to [assume] some people have more information than others".

Conspiracy theories are born out of the murky feeling that not all is being revealed to us, that the truth is still in shadow, and someone else is pulling the strings. During a fast-moving pandemic, where news breaks faster than scientists can make reliable findings, false credibility can attach to seemingly plausible explanations.

In this case, real crackdowns by Chinese police on doctors who raised the alarm about early cases of the mystery illness did not help, along with China’s record of covering up the extent of the SARS outbreak in 2002. This time around, US intelligence says history may be repeating itself, as it queries both the nation’s total reported cases and deaths from COVID-19.

Klein specialises in the philosophy of neuroscience, and a research project on misinformation has meant he's spent a lot of time on internet conspiracy theory forums where, for months already, there have been "quite a variety of COVID-19-related stuff".

"Nobody has the full story yet," he says. "Government and news outlets [haven’t] been super-reassuring – it may just be because there’s no reassurance to be had."

But it's not the first time the high-anxiety narrative of an outbreak has sent imaginations running wild. When the infamous 1918 Spanish flu finished its lethal sweep across the world at the end of World War I, it had claimed more lives than the war itself. And in the absence of a known source, stories quickly spread that the Germans had developed the virus as a new kind of weapon.

Nearly 100 years later, Ebola was also wrongly called a biological weapon when it began its major rampage across Africa in 2014; and the Zika crisis of 2015 was blamed on everything from vaccinations to genetically engineered mosquitoes. A recent paper found that attempts to debunk these false Zika theories in Brazil at the time were wildly unsuccessful – if anything they just left people feeling less certain about all information coming to them, even from official channels. But when yellow fever emerged in the same region just a few years later, efforts to counter the same inevitable deluge of misinformation had more impact – suggesting that conspiracies are harder to combat when a disease is new with less reliable information about it.

The current Wuhan bioweapon conspiracy theory echoes the famous Cold War-era Operation Infektion when the KGB spread the lie that HIV was created in a US biological weapons laboratory at Fort Detrick in the US state of Maryland – right near where, coincidentally, Klein himself grew up.

All these diseases actually came from animals – as 70 per cent of all new pathogens emerging in humans do. As people push further and further into the world’s last wild places, such "spillovers" are happening more and more. The solution, experts say, is getting ahead of them, monitoring viruses circulating in likely carrier species such as bats and rethinking our riskier interactions with wildlife (including caging them for meat and parts or forcing them into populated areas by clearing forests). But conspiracy theories distract from this; often, they become a smokescreen themselves.

US disease ecologist Dr Jon Epstein has been working with scientists such as Shi for the past 15 years to monitor animal viruses – together they even traced the original SARS strain back to a colony of bats. The "scientific evidence is overwhelming" that COVID-19 came from bats, too, he says. "And we’ve been warning about it for a long time."

As the science crystallises, conspiracy theories will sink to the bottom of the conversation again. It’s already starting, Epstein says. But in the meantime, in the realm of public health, they can do real damage.

How are politicians using the crisis for their own agendas?

Pandemics are frightening, fluid beasts and that makes them ripe for misinformation, warns Jessica Brandt, head of policy at the Alliance for Securing Democracy in Washington, DC. "This time, the response has unfortunately become politicised," she says.

Both China and the US have come under fire for wasting crucial time in responding to the outbreak. And they've also attracted most of the blame in biological weapon theories circulating online. But officials in both countries have spread plenty of their own conspiratorial notions too, trading blows in the war of messaging as the pandemic picks up steam.

In the US, some conservatives have sought to recast the crisis as one of Chinese military aggression rather than a failure by China's government to contain the outbreak. President Donald Trump's former chief strategist, Steve Bannon, and even US Senator Tom Cotton pointed to the Wuhan lab as its origin. And in recent days the president himself and his officials have begun flirting with the theory too, offering no further evidence but demanding answers from China.

“More and more, we’re hearing the story,” Trump told reporters in Washington. Secretary of State Mike Pompeo added: “The mere fact that we don’t know the answers – that China hasn’t shared the answers – I think is very, very telling.”

Meanwhile, Chinese officials have been conjuring up the same theories, only with their own anti-Western twist. While the government had at first blamed the outbreak on the "illegal wildlife trade", by March Foreign Ministry spokesman Lijian Zhao was tweeting articles from a known conspiracy theory site linking COVID-19 to Fort Detrick’s biowarfare program and even a recent US army stopover in Wuhan. Add to this loud efforts by Iran (and more stealthy online campaigns from Russian bots and pro-Kremlin media sites) to further sow doubt about the natural origins of the virus.

Klein notes that conspiracy theories tend to track political interests, with COVID-19 being connected to a variety of agendas: "It’s being done to undermine Trump; [it] is being done to put in an authoritarian state; or get us ready for all having to be locked in our homes; or it’s being done to kill off the poor."

In Washington DC, information warfare expert Molly McKew says there is certainly a political divide in conspiracy narratives right now, but distrust in institutions fuels common theories for everyone.

"Ideas about martial law and a massive expansion in government power make Americans of both sides of the political spectrum nervous," she says. "People are quick to share rumours about emergency powers and expanded surveillance, some of it real or some of it not."

In the US, for example, as cities went into lockdown to stem the spread of COVID-19, people were panic-buying not just groceries but guns.

What makes a really good conspiracy theory?

To some extent, the same thing that makes a good Hollywood thriller, says Klein. First, there's the basic structure, the classic dramatic arc with a beginning, conflict and perhaps even a resolution – unlike the more messy and incomplete tale of COVID-19. "Somebody eats a bat and they get kind of sick and nobody notices for a while and then everybody gets kind of sick is not a very satisfying story," says Klein. "If you were to take that to your short-story writing class, people would say: 'That’s a terrible story. Come back later'."

Then there is mood. There's a very real sense of "obscure danger" to COVID-19 as it unfolds, and that plays straight into a more elaborate narrative.

"You don’t know where it came from, who has it or who doesn’t – where it might come from next," Klein says. "It could be anybody, it could be the person next to you on the bus. That’s a good device for building dramatic tension, right? [Like the] great old movie The Thing with Kurt Russell, with a shape-shifting alien – that’s a great set-up and I think pandemics have a similar feeling to them."

Where does the toilet paper hoarding fit in, though? "It’s weird that people go for this," says Klein. "But pandemics touch on this feeling of vulnerability about your body and your health and people’s panic reaction is not to buy a bunch of quinoa, it’s to buy toilet paper – to buy things that are about cleanliness and purity to ward off the disease. In general, feelings about purity and cleanliness make for good stories, [they] can be emotionally powerful."

Is there a typical profile of a conspiracy theorist?

Some people have a conspiracy mindset. Perhaps they distrust institutions or feel disempowered by the status quo. They can be someone sharing a meme on Facebook all the way through to what Klein describes as those with "lots of things on [the] wall with yarn going between them", making connections where they want to find them.

But more commonly, people harbour conspiracy beliefs on topics that push their buttons. "Someone has a bad experience with the police, maybe that primes them [to believe in police cover-ups]," Klein says. "It’s not outlandish in the US to think that the police killed somebody and covered it up, because that actually happens. It’s probably wrong – but it’s not crazy."

Is the internet to blame?

There's no doubt cyberspace is fertile ground for conspiracy theories – as with the theories themselves, everything on the web is connected. Social media algorithms favour content that generates high emotional responses in people over rational or verified sites. With no fact-checkers built into platforms, a seductive conspiracy theory has little barrier from spreading: all it needs is people to react.

But these theories don't only crop up online, they can surface in popular music, around the dinner table, even in mainstream media. And they didn't begin with the internet age – the US alone has a long history of conspiratorial thinking. False accusations that the British were secretly planning to enslave the American colonists even helped spark revolution in 1775. In a famous 1964 essay on The Paranoid Style in American Thinking, historian Richard Hofstadter describes conspiratorial types "always manning the barricades of civilisation". But it is "the use of paranoid modes of expression by more or less normal people that makes the phenomenon significant," he says.

How do you argue with a conspiracy theorist?

There’s little point, says Klein, given the self-reinforcing nature of the theories themselves. "I could say, ‘it’s wrong’, but that just shows I’m part of the conspiracy, too: Professor Obviously in League With the Government Helping Them Cover It Up."

In a similar vein, Facebook or YouTube removing conspiratorial misinformation can serve to make people feel like something is being suppressed.

Why people continue to believe such stories in spite of scientific rebuttal reflects the reality of our information environment today, says Brandt. "Lies travel faster than facts and, perversely, efforts to debunk a conspiracy theory can end up reinforcing it."

But some say the new ability for such theories to catch on in the mainstream through the fast, supercharged medium of the internet means they can’t just be ignored either. While banning a shock jock such as the American Alex Jones for peddling falsehoods online might make him a martyr to his devoted followers, it could also stop him reaching new audiences. And some studies suggest dismantling theories with logic can actually work – especially when the person pointing out the holes in the story is perceived to be smart and competent.

Increasingly, authorities treat such misinformation contagion like their biological equivalent – proactively pushing out the right facts to inoculate people against unfounded theories or encouraging good information hygiene (such as checking sources). Even before COVID-19 had exploded into a pandemic, the World Health Organisation had teamed up with the likes of Google and Facebook to try to reach audiences with its own set of facts before conspiracy theorists could.

These days, Klein says he considers such theories more as symptoms of a bigger problem, whether it be lack of transparency or a failure of communication.

"I think just trying to tackle ... conspiracy theories on their own doesn’t do much compared to trying to figure out why people believe these things and what you can do to stop that broader problem," he says.

For most people, the more consistent and clear the messaging is from the people higher up, the better – even if that information is "we don't know yet".

"But there’s a sense in which trying to engage with full-bore conspiracy theorists just, at best, sucks you deeper into what they believe," Klein says.

"Once you fully get in, it’s very hard to get out."

With Anthony Galloway