When reports of a new coronavirus emerged last month, I speculated with fellow epidemiologists about what the media might end up naming the infection. None of us would have guessed that within a week or so a theory would be circulating that coronavirus was a new kind of “snake flu”– mostly because it’s unlikely the virus originated in snakes, and it’s not flu.

So where did the snakes come from? The culprit was a widely shared scientific paper, which speculated that the new virus had genetic characteristics and implicated snakes as the source. Leading geneticists were quick to point out that the results weren’t convincing, and that bats were still the likely suspects. However, that didn’t stop snake flu from going viral. Other misinformation about coronavirus has rippled across the internet in recent weeks. From claims the virus is part-HIV to conspiracy theories about bioweapons and reports suggesting the virus was linked to people eating bat soup, stories sparking fear seem to have overtaken the outbreak in real life. Is misinformation really more contagious than the virus itself?

Quick Guide What are coronavirus symptoms and should I go to a doctor? Show What is Covid-19? Covid-19 is caused by a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals. The World Health Organization (WHO) has declared it a pandemic. What are the symptoms this coronavirus causes? According to the WHO, the most common symptoms of Covid-19 are fever, tiredness and a dry cough. Some patients may also have a runny nose, sore throat, nasal congestion and aches and pains or diarrhoea. Some people report losing their sense of taste and/or smell. About 80% of people who get Covid-19 experience a mild case – about as serious as a regular cold – and recover without needing any special treatment. About one in six people, the WHO says, become seriously ill. The elderly and people with underlying medical problems like high blood pressure, heart problems or diabetes, or chronic respiratory conditions, are at a greater risk of serious illness from Covid-19. In the UK, the National health Service (NHS) has identified the specific symptoms to look for as experiencing either: a high temperature - you feel hot to touch on your chest or back

a new continuous cough - this means you’ve started coughing repeatedly As this is viral pneumonia, antibiotics are of no use. The antiviral drugs we have against flu will not work, and there is currently no vaccine. Recovery depends on the strength of the immune system. Should I go to the doctor if I have a cough? Medical advice varies around the world - with many countries imposing travel bans and lockdowns to try and prevent the spread of the virus. In many place people are being told to stay at home rather than visit a doctor of hospital in person. Check with your local authorities. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

We typically think of viral content as a chain reaction: you share something with friends, they share it with their friends, and so on. In disease outbreak analysis, we can measure the transmission of an infection by looking at how many additional cases each infected person creates on average during each of these steps. We call this the “reproduction number”, and for coronavirus, we estimate it’s about 2 for a typical infected case in China. What about the reproduction number for online content? A couple of years ago, Facebook researchers looked at the most shared content on the platform from 2014 to 2016, including viral trends such as the ice-bucket challenge and putting an equals sign over your profile picture to support marriage equality.

Remarkably, there wasn’t much difference in the transmission. Researchers found the reproduction number was about 2 for all of them. Remember, these were the most shared ideas on Facebook; the vast majority of online content is lucky to get even a single repost.

The scientific community is making huge progress in understanding the infection, but we’ve had to start at the bottom

To fully explain how viral content – and viruses – spread, we need to move away from the idea that outbreaks involve simple clockwork infections, passing along a chain from person to person to person until large numbers have been exposed. During the 2015 outbreak of the Mers coronavirus in South Korea, 82 out of 186 infections came from a single “superspreading event” in a hospital where an infected person was being treated. It’s not yet clear how common such superspreading is in the current outbreak, but we do know that these kinds of events are how information goes viral online; most outbreaks on Twitter are dominated by a handful of individuals or media outlets, which are responsible for a large proportion of transmission. If you heard about snake flu, you might have told a couple of friends; meanwhile, newspaper headlines were telling millions.

When tackling disease outbreaks, health agencies often work to identify potential superspreading events, isolating infected individuals to prevent further transmission. However, this isn’t the only way to stop an outbreak. As well as tracking down people who are infectious, it’s possible to target broader social interactions that might amplify transmission. For example, many cities in China have recently closed schools, which can be hotspots for respiratory infections.

Tech companies are now adopting similar approaches to tackle health misinformation. Last year, Pinterest announced it had rewired its search results to make it harder to find vaccine misinformation. It had struggled to remove the content completely – the equivalent of finding all the cases during a disease outbreak – so instead focused on reducing how many people might be exposed to harmful content. During the current outbreak, Google is attempting to reduce people’s susceptibility to misinformation by displaying links to reputable health sources when users search for information about the virus.

These combined approaches, which target different aspects of transmission, have long been used in disease control. By introducing analogous strategies online, we should have a better chance of effectively curbing harmful viral content.

Ensuring the public has the best possible health information is crucial during an outbreak. At best, misinformation can distract from important messages. At worst, it can lead to behaviour that amplifies disease transmission. The novelty of coronavirus makes the challenge even greater, because viral speculation can easily overwhelm the limited information we do have. The scientific community is already making huge progress in understanding the infection, but we’ve had to start at the bottom, without stacks of earlier research to stand on. When it comes to stopping the outbreak, we’ll need ladders, not snakes.

• Adam Kucharski an epidemiologist and the author of The Rules of Contagion: Why Things Spread – and Why They Stop