In the weeks after the new coronavirus began to spread, Sydney doctor Danforn Lim discovered some of his patients had mistaken theories about masks.

For example, they thought respiratory masks could be recycled and sanitised by being steamed or microwaved — misinformation he believes was shared globally on messaging platforms like WeChat and WhatsApp.

Key points: Misinformation about the novel coronavirus is spreading on social media

Misinformation about the novel coronavirus is spreading on social media Studies suggest challenging conspiracy theories with facts may not work, and can backfire

Studies suggest challenging conspiracy theories with facts may not work, and can backfire Experts argue we need a comprehensive public health campaign

Dr Lim, who is senior vice president of the Australian Chinese Medical Association (NSW), said people can share rumours and ill-advised advice online without the intention of harming others.

"They don't understand the consequences of forwarding an unverifiable source of information," he added.

While the novel coronavirus outbreak seems to have begun in the city of Wuhan, its spread has been matched online by the circulation of half-truths and paranoia about the cause of the disease, and how to prevent it.

We're told to wash our hands and stay at home to avoid spreading viral diseases like the flu.

But on social media and messaging apps, where a post made in New York can reach the suburbs of Sydney at a blistering pace, there are conflicting messages about how best to fight contagion.

And in some situations, efforts by public health authorities to directly combat misinformation could have an unintended and even opposite effect.

'Tainted truth'

Epidemics and outbreaks are often accompanied by conspiracy theories and misinformation, as was the case in Brazil in 2015 and 2016 during an outbreak of the mosquito-born Zika virus.

As fear grew, so did conspiracy theories — that the outbreak was caused by genetically modified insects, for example, or that the accompanying increase in microcephaly in infants was due to prenatal vaccines.

A study, recently published in the journal Science Advances, examined how people in Brazil responded to public health messages that attempted to correct these theories.

The findings "were not encouraging", according to Dr Brendan Nyhan, a professor in the Department of Government at Dartmouth College, and one of the study's co-authors.

In general, the team's online survey results found no measurable effect of giving people information that countered conspiracy theories.

Revellers in a Rio de Janeiro street parade raise awareness about the spread of the Zika virus. ( AFP: Christophe Simon )

In fact, doing this seemed to have "negative spill overs" to other beliefs people held about Zika. In other words, it appeared to shake their belief in even accurate facts about the Zika virus.

"It seemed to have made them question the certainty with which they held these beliefs, or reduced their confidence in them in some way," Dr Nyhan explained.

"It seems like people, once they've heard that [the conspiracy theories] are untrue, come to disbelieve other things they've heard about Zika, irrespective of … their accuracy."

While each country is different, and the survey takers were found to be more white, educated, and wealthy than the Brazilian population, the study presents a challenge for those hoping to halt the spread of conspiracy theories during an outbreak.

'Setting the record straight over and over again'

In China, where the coronavirus outbreak is more extensive, anxiety about the disease is naturally high.

But because rumours are easily spread on social media and among communities, they filter through to Australians, encouraging an unwarranted level of paranoia.

For example, at Westmead Hospital in Sydney, Dr Dominic Dwyer has fielded questions like, "Should I be in public places?" and "Should I be going to Chinese restaurants?" — even though health authorities here have issued no such advice in Australia.

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He also sees an undercurrent of anti-Chinese racism in some of the misinformation that's spread.

"If it happened in Australia, we'd be horrified if people saw us as bringers of disease and death," said Dr Dwyer, director of the Institute of Clinical Pathology and Medical Research.

For people who aren't medically trained, it can be difficult to understand how disease spreads. Identifying a singular bad actor or group to blame is often simpler.

The instinct of authorities, doctors and media is often to combat false information directly with accurate information, but when messages, tweets and posts are rapidly proliferating, where would you even begin?

"It begins to feel like a game of whack-a-mole," Dr Nyhan commented.

"And in that context, people may try just setting the record straight over and over again."

Trying to directly counteract misinformation can often have unforeseen effects, agreed Dr Margaret Heffernan, who studies health policy at RMIT University.

"Undercutting the initial beliefs of people is very difficult because it is tied into their ideologies," she said.

The challenge of the new

The Dartmouth research team also looked at a subsequent outbreak in Brazil of yellow fever in 2018.

Interestingly, for this disease, which is much better known, corrective information reduced misperceptions about yellow fever and didn't create the same level of negative spill overs observed with Zika beliefs.

This suggests there may be something about the newness of outbreaks like the coronavirus that makes misinformation particularly difficult to confront.

Dr Heffernan said Australia needs a period of intensive public health messaging to share facts about the coronavirus, and more education about best practices around respiratory health in general.

Accurate public health messages need to have a better and more appropriate presence online, and doctors will need patience to change the minds of people who cling to dangerous health beliefs.

Dr Nyhan said he still wants to know more about how much misconceptions contribute to the harms of a disease.

If false beliefs are directly leading to public harm, and they can be effectively corrected, then that must be part of the public health response. But we don't know that for certain.

"If these misconceptions are largely an expression of people's fears and they're not doing additional damage, it may be the case that focusing on the misconceptions is actually the wrong kind of approach," he said.

Day to day, though, doctors still must deal with the bad information circulating about the novel coronavirus.

Dr Lim tells his patients to "fact check" with their GP.

"Verify it with the government website or university sources," he said.