Anti-vaxxers, who generally believe that there is a high risk that vaccines cause serious side-effects such as autism, hate the term “anti-vaxxer”. They believe it to be insulting and prejudicial, used to shut down debate rather than engage with what they believe to be rational arguments and legitimate fears. True, the term is designed to do that, because refuting the myth that vaccines pose more risk than benefit has become tiresome after 20 years in the trenches.

It is true that treating vaccine sceptics – as I imagine they’d prefer to be called – with disdain might be counterproductive. Nobody likes to be told they’re an idiot, or worse, that they’re endangering their own children. Doing so tends to harden their position, making them defiant in the face of better evidence. They feel “brave” to stand up for their convictions.

Such people search for affirmation from fellow-travellers online and cherry-pick evidence that suggests they might be right. Inevitably, they conclude that the media conspires with scientists, doctors, Big Pharma and governments to silence their dissent.

Many parents are, understandably, eager to do the best they possibly can for their children. However, parents do not always know what’s best. Worse, they often do not know enough to know that they don’t know.

This is known as the Dunning-Kruger effect. A recent survey reveals that the less people truly know about how vaccines work, the risks associated with vaccines, and their role in public health, the more they think they know. More than a third of survey respondents claimed to know more than doctors and scientists about vaccines and the causes of autism.

When lay people research vaccination, they come across reams of information about so-called “vaccine injuries”. This makes it easy to conclude that it is safer to space out vaccinations, choose only some vaccinations, or not get children vaccinated at all.

So let’s take some of their arguments seriously for a while, and see if they hold up under even cursory scrutiny.

It is true that one ought to be sceptical of governments. They routinely prove to be incompetent, heavy-handed, and misguided. They tend to excessive authoritarianism.

It is also true one ought to be sceptical of big business. They routinely prove to be manipulative and corrupt, harnessing the power of government to protect profits, rather than fairly earning them in a free open market.

It is true one ought to be sceptical about so-called “experts”, in particular when it comes to health. There are millions of quacks out there, and many more legitimate doctors and scientific researchers who base opinions upon weak findings and trumpet them to boost their own careers.

A case in point is the official dietary advice promoted for over four decades by governments, scientists and doctors, that full-fat dairy products are harmful to one’s health because dairy fats cause cardiovascular disease (CVD), coronary heart disease (CHD) and stroke. They don’t.

We all believed them, but we were wrong. Worse, in our zeal to swear off saturated fats, we switched to sugar for comfort, too much of which does make us fat and unhealthy. The experts, both scientific and governmental, do sometimes give wrong advice.

However, science is a progressive enterprise. Careers are made by discovering new things, or proving old ideas wrong. The idea that medical researchers are deliberately suppressing knowledge about vaccine harm, in order to advance a mandatory vaccination agenda, is far-fetched. That experts are sometimes wrong is not a sound basis for dismissing expert consensus on any particular issue.

Much of the anti-vaccine myth arose from a discredited paper published by Andrew Wakefield 20 years ago. In it, he identified gastrointestinal disease in 12 children, of which nine also developed developmental regression (autism). Another one developed disintegrative psychosis, and in the remaining two he claims to have identified “possible postviral or vaccinal encephalitis”.

He said that parents linked the behavioural symptoms with the measles, mumps and rubella vaccine, and his interpretation noted that the physical and mental symptoms were “generally associated in time with possible environmental triggers,” i.e. vaccinations.

There are those who defend Wakefield, arguing that the media and medical establishment pilloried him unfairly. In particular, they say that the media deliberately lies about his study, wilfully misrepresenting it because it explicitly did not prove an association between the MMR vaccine and autism.

Indeed, it didn’t. However, he did claim that there was a link, despite the fact that “association in time” is hardly a link at all. Autism symptoms appear at about the same age an MMR vaccine is administered, even in non-vaccinated children. To claim, as Wakefield did, that a mere temporal association is any link at all, is the real lie.

Journalist Brian Deer of the British Sunday Times newspaper exposed Wakefield as a scientific fraud and a paid shill for trial lawyers. He showed his paper to be bogus, and his medical records as falsified. His paper was retracted, and Wakefield’s medical licence was revoked for serious scientific misconduct.

Some modern vaccination sceptics continue to view Wakefield as a martyr for the truth. Others, however, have tried to distance themselves from him, complaining that pointing to Wakefield is an overly simplistic counterargument to vaccine scepticism. They modified their argument, saying that autism is not the only concern with vaccines. Like any other drug, vaccines have side-effects, which can be harmful, they argue.

This is clever sleight-of-hand. A few cases of “vaccine injury” are established not in scientific settings, but in civil courts, where the standards of evidence are far, far lower. Most cases, called “adverse events” in medical parlance, take the form of case reports, not clinical trials.

A case report may be published when something interesting and unusual happens. Nobody publishes case reports about things that happen all the time, which should be evidence enough that “vaccine injury” is a very rare occurrence. The plural of “anecdote” is not “data”.

The US Centers for Disease Control maintains a Vaccine Adverse Events Reporting System (VAERS). It records adverse events, no matter the severity, that occur after vaccination. Being listed in VAERS does not imply confirmation that an event was indeed caused by vaccination. The event could have been, and usually is, entirely coincidental. In fact, because these reports are unverified, drawing conclusions from them should be done with great caution.

Most vaccine event reports in the VAERS database involve minor side-effects such as injection-site pain or mild fever. Only 14% of the reports can be described as serious.

If we were to throw caution to the wind and assume all serious adverse events recorded in VAERS were vaccine-related, this would imply a serious adverse reaction in about one in 100,000 vaccinations. The true rate is probably closer to one in a million.

Now weigh this against the risk of not vaccinating children. Vaccination has been the greatest medical advance of the 20^th century. Since the discovery of vaccines, smallpox has been wiped out entirely, and many other serious diseases that can cause death or disability – among them poliomyelitis, tetanus, diphtheria, pertussis, rabies, haemophilus influenza type B, chicken pox, measles, mumps, and rubella – have been largely controlled in many parts of the world.

Ironically, this means that people have forgotten how serious these diseases could be. True, many of us had them without any lasting effects, but that is not true for everyone. Because these diseases are now more rare, people have forgotten the scarring, the complications, the permanent disabilities, and the death rate. They intuitively sense that the risk is not so great, when the only reason for that perception is the great success of vaccination programmes.

Recent outbreaks of measles in countries that once thought to have had the disease under control are directly correlated with declining vaccination rates because people believe them to do more harm than good. It would be truly awful if a failure to vaccinate resulted in the return of, for example, polio, to the risks our children face.

Some argue that mumps, chickenpox and rubella are less dangerous than smallpox, measles and polio. Statistically this might be true, but these diseases are far from harmless. Mumps can cause encephalitis, meningitis and hearing loss. In post-puberty boys, mumps can cause sterility.

Chicken pox used to be very common and is rarely serious, but can cause severe complications such as pneumonia, encephalitis, bleeding, sepsis, and even death. It also was a common cause of long-term scarring, leading to life-long self-esteem issues among sufferers.

Rubella (German measles) can cause encephalitis and bleeding problems, but is especially dangerous to pregnant women, among whom it can cause severe birth defects in unborn children.

All of these diseases can be catastrophic for people with compromised immune systems, such as those with an immune disorder or undergoing cancer treatment.

Herd immunity is achieved at high vaccination rates – 95% or higher – when a contagious disease outbreak has a low likelihood of spreading because there just aren’t enough susceptible people to spread it to. The ideal of herd immunity critically depends on the participation of all those who do not have a sound medical reason for not being vaccinated.

I’ve heard a number of people say that they’d rather not vaccinate their children, because they are protected by herd immunity anyway. Not only is this position supremely selfish, but if even a small fraction of other people thought the same, herd immunity would be compromised, and those children would be just as vulnerable as children who cannot be vaccinated for medical reasons.

Some vaccination sceptics argue that vaccines are not always effective. Of course they’re not. No drug is 100% effective. Using that as an excuse to forgo vaccination altogether is simply absurd. If your child can get a 95% chance of protection against a serious disease, or an 80% chance of protection, or a 50% chance, is that not better than no protection at all?

Other people prefer to space out their children’s vaccinations. Their belief is that too many vaccines at once, or in a short space of time, can “overload” a child’s immune system. Although this belief is widely documented, there is no medical evidence to support it.

Studies have shown that adverse events are no more frequent when vaccines are administered together than when they are given separately.

One popular advocate of so-called “alternative vaccination schedules” is Dr Robert Sears. However, Dr Bob, as he is commonly known, admits himself that the alternative schedule is untenable, warning his readers not to share their fears with others, so they can take advantage of herd immunity to mitigate the risk of spreading out vaccinations.

Vaccination schedules are designed for optimum effectiveness, making sure that children are protected as early as possible, and that there aren’t any gaps that leave them vulnerable to disease. It is only by the Dunning-Kruger effect that a parent could second-guess the recommended vaccination schedules proposed by doctors.

Some argue that during an outbreak of a disease such as measles, more vaccinated than unvaccinated people fall ill. That is often not even numerically true, but when it is, it betrays a failure to grasp basic arithmetic. Because the share of the population that has been vaccinated is much larger than the share of unvaccinated people, a much smaller percentage of cases among the vaccinated can exceed the absolute number of cases in the unvaccinated population. The true measure is what percentage of vaccinated people get sick, compared to the percentage of unvaccinated people who do. In that comparison, the vaccinated population always wins out.

Then there are those who say that in a modern society, hygiene and improved nutrition have contributed far more to the control of disease than vaccination. This is not borne out by any medical research, however. Making such claims is easy when they seem intuitively plausible, but such claims require evidence, which is never forthcoming. On the contrary: the sharp drop in disease cases in the years after the introduction of a vaccine proves that hygiene and nutrition, which improve only slowly, contribute far less to immunity than vaccines do.

Just because the majority of doctors, government bureaucrats and journalists reach the same conclusion about vaccinations – that their benefits far outweigh their risks – does not mean there is a conspiracy to silence anyone. The problem is simply that the sceptics do not have the scientific evidence on their side.

That is why, no matter how much they try to weasel their way out of the shadow of the Wakefield fraud, they remain wrong. And that is why they’ll continue to be derided as anti-vaxxers and even “baby-killers”.

Vaccine sceptics would like to be taken seriously, but their arguments, and the facts, simply do not support doing so. DM