Conspiracy theories about coronavirus have become so widespread that they’re now generating news stories in the national media and provoking public reactions from government ministers. The most popular seems to be one that links the pandemic to the roll-out of 5G mobile technology. At the beginning of the year, the UK government finally approved the Chinese company Huawei as a supplier of equipment for 5G, after a very public controversy in which critics, many of them on the right of the Conservative Party, voiced objections on the grounds that they believed the company had close connections with the Chinese government. Where is Huawei's research centre? In Wuhan. And what else was there in Wuhan? The Wuhan Institute of Virology, a top-level research centre. And where did the coronavirus start? Why, in Wuhan too. And when? Just as the roll-out of 5G was beginning.

It didn’t take long for the conspiracy theorists to join the dots. The virus was man-made, created in a laboratory in Wuhan, part of a Chinese plot to develop biological warfare systems. The masts were spreading the virus through high-frequency emissions. The virus was designed to suppress the human immune system. Or to suck oxygen out of the lungs. Ultimately it aimed to reduce the population of the West and undermine its economies. There weren’t any cases in Africa because 5G hadn’t been set up there.

In the meantime, 5G masts have been going up all over Britain to enable its adoption. Anti-5G organisations, such as Stop 5G UK, which has 27,000 members in its Facebook group, have claimed that the masts’ radiation damages people’s health and lowers their fertility (shades of the film Dr Strangelove here); and they have embraced the new conspiracy theory as further evidence of the dangers posed by the system. In a recent TV interview with London Live, the conspiracy theorist David Icke has referred to an “electro-magnetic technologically generated soup of radiation toxicity”, which he claimed damaged old people’s immune systems.

But medical authorities have confirmed there’s no evidence that the masts are harmful to human health or that the virus was developed in a laboratory (similar conspiracy theories made the same unfounded allegation a few decades ago about HIV and Aids). And there are cases of coronavirus in Africa. The national medical director for England, Stephen Powis, has said: “The 5G story is complete and utter rubbish, it's nonsense, it's the worst kind of fake news.”

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The paranoid fantasies of conspiracy theorists sometimes have consequences in the real world. During the US presidential election campaign in 2016, a story generated by a white-supremacist website alleged that top campaign officials of the Democratic Party were running a Satanic child sex abuse ring centred on pizza parlours in Washington, DC. One of these, the Comet Ping Pong, was said to have kept sex slaves in its cellar. A young man then appeared in the restaurant and fired three shots from a rifle (fortunately not injuring anyone), demanding to inspect the cellar. There was no cellar underneath the Comet Ping Pong, however, and he was arrested. The conspiracy theory was subsequently comprehensively discredited, by the Washington police among others.

The 5G coronavirus conspiracy theory has also spilled over from social media into real life. “It is time to act now,” read one tweet: “Any 5G tower in your area burn it down! Collect people and stand and fight this. Act now before it’s too late!” Some anti-5G campaigners took this exhortation literally and began attacking the masts. So far, six have been burned down in locations ranging from Birmingham to Belfast. This has alarmed non-violent protest groups. A post on an anti-5G Facebook page has expressed alarm about individuals who “have decided to target telecoms workers, as they believe and claim them to be ‘criminals’ and ‘genocidists’”. Employees of OpenReach, which is involved in upgrading mobile phone masts, have posted on anti-5G websites, pleading not to be shouted at or verbally abused in the street; in most cases, in fact, they are not working on the masts anyway. Social media companies have taken down posts urging or applauding the destruction of masts. Medical commentators have pointed out that mobile phone networks are essential for organising the fight against the epidemic and attacking them is not just counterproductive, it’s also dangerous.

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This seems a very 21st-century panic, involving 21st-century means of communication such as Facebook and Twitter. And yet it’s also just the latest version of a very old phenomenon. When the previously unknown and deadly disease cholera broke out in Britain in the early 1830s, having left the Indian subcontinent and swept across Europe, enraged mobs began to attack doctors on the street, accusing them of taking alleged cholera victims to hospitals in order to kill them and use them for dissections in the anatomy schools. “Bring out the Burkers!” was one popular cry, alluding to the scandal caused in 1828 when two Edinburgh men, Burke and Hare, were convicted of murdering 16 people in order to sell them to the anatomy schools. Crowds hunted down anybody in a white coat through the streets of towns along the Volga during the Russian cholera epidemic of 1892, believing they were spreading the disease as part of a government-led conspiracy to reduce the numbers of the poor.

New diseases with a major impact on society tend to generate conspiracy theories because those people under threat grasp for easily comprehensible explanations, especially when medicine, as with cholera, seems unable to deal with the outbreak. Conspiracy theories appeal to people looking for someone to blame for a disaster, real or impending, not least because they always ascribe intention and purpose in their search for culprits; the conspiracist mentality refuses to accept that major events can happen without human agency. Conspiracy theories spread faster and wider today because of the internet, but their basic structure and modus operandi are not much changed from the days of word-of-mouth transmission, as with theories blaming cholera deaths on “Burkers”,

What’s striking about conspiracy theories is how impervious their most diehard supporters are to scientific evidence or expert opinion. Government ministers, scientists and medical authorities quite rightly go to great lengths to demonstrate the falsity and often the danger of such theories, and in the case of coronavirus, they are overwhelmingly backed by the popular press. But while they may be able to calm public opinion and persuade the great majority of citizens to take their advice, there is still, as in the great epidemics of the past, a hard core of disbelievers who dismiss “official” sources and turn to each other for information (or misinformation) instead. They form self-sealing communities of alternative knowledge, reinforcing their conviction that they know better, remaining impervious to any real evidence.

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Conspiracy theories like this often tap into suspicion of foreigners. You can plot the progress of syphilis across Europe in the 1390s, after it was introduced by Christopher Columbus’s crew when they returned from the Americas, by the names it was given: the “French sickness” in Germany, the “German sickness” in Poland, the “Polish sickness” in Russia, “the disease of the Christians” in Turkey, “the disease of the Turks” in Persia, and so on. The 15th-century Portuguese explorer Vasco da Gama and his crew took it with them to the Indies and Japan, where its origins were indicated by the name “the Portuguese sickness”, while “the British sickness” eventually spread to Tahiti and the Pacific in the course of the 18th century. In the same way, President Trump has called coronavirus “the Chinese virus”, the Russians have accused the Americans of inventing it in order to boost the profits of drug and medical companies, and conspiracy theorists in one country have pointed the finger at scientists and governments in another.

Since pandemics by definition spread across the globe, everywhere they arrive they come from somewhere else. It’s never long before nationalists and xenophobes begin to use them to stoke hostility to outsiders. During the coronavirus pandemic, people of East Asian appearance have been subject to verbal and sometimes physical abuse in many countries, as if somehow all of them have just arrived from Wuhan. In the US over a thousand such incidents were logged in the space of a few weeks in February and early March. Here too there are historical parallels, including relatively recent ones: between 2003 and 2008 the government of President Thabo Mbeki in South Africa dismissed antiretroviral drugs as a plot hatched by Western drug companies in order to boost their profits, based on neo-colonialist racist stereotypes, and refused to sanction their distribution. Members of his government denied that HIV was spread by sexual contact and recommended herbal remedies instead. Hundreds of thousands of people in South Africa died needlessly of Aids as a result.

Much further back in time, in 1349, when the Black Death – bubonic plague, spread by bacteria carried by fleas – swept across Europe, killing half or more of the entire population, western Europe’s main religious minority, the Jews, were widely accused of poisoning the wells. In many places, above all the Rhineland, they were massacred in large numbers: in Strasbourg several hundred were burned alive. When cholera struck the US in the early 1830s, Irish immigrants were blamed; in 1899 an outbreak of bubonic plague in Honolulu, though limited, led to attacks by an outraged mob on the Chinese quarter, which was burned to the ground.

Conspiracy theories have been associated with epidemic disease throughout history: in that sense, the 5G hysteria is nothing new. What is new, however, is that we are better equipped than ever to counter it with scientific knowledge and reliable medical information. While the most die-hard conspiracists will never be persuaded, we can surely do more to prevent their dangerous fantasies from getting into the communications mainstream. Public education on coronavirus in the UK has started late, but it’s now well under way. Social media platforms have thankfully begun to ban groups and individuals who peddle anti-5G hysteria, the latest being David Icke. Reliable medical information is now almost universally and very publicly available. At least it’s a start.