Vaccines prevent diseases that are dangerous and sometimes deadly.
It’s certainly safer to have a tetanus jab than to be left at risk of complications from an infected wound, and childhood vaccinations against polio have banished the paralysing condition from all but three countries.
But fear of vaccines has existed since the first one was introduced against smallpox in 1796. People believed the vaccination, which contained traces of the less dangerous cowpox virus, would cause them to sprout bovine features – a concern illustrated in cartoons at the time.
Smallpox has now been eradicated, but suspicion of vaccines remains. Even the most powerful man in the world, Donald Trump, has indicated he believes they can cause autism, despite conclusive scientific evidence to the contrary.
Vaccination is not completely risk-free, but side-effects are extremely rare and medical professionals worldwide agree the benefits far outweigh the risks.
Does the MMR jab cause autism?
Exhaustive scientific research has concluded that no, the measles, mumps and rubella vaccine does not cause autism.
A comprehensive review of 10 different studies, using data from 1.2 million children, was carried out in 2014 and did not find any relationship between MMR and autism spectrum disorder.
Around 24,000 children are not immunised against the three infectious diseases each year in England, according to Public Health England, with a number of parents choosing not to vaccinate their children due to fear of potentially dangerous side-effects.
Donald Trump has also suggested autism can be caused by immunisation, tweeting: “Healthy young child goes to doctor, gets pumped with massive shot of many vaccines, doesn't feel good and changes - AUTISM. Many such cases!”
The MMR vaccine has been in use since 1971, but the controversy surrounding it began in 1998 when former doctor Andrew Wakefield published a research paper in The Lancet claiming to show a link between the combined jab and autism.
“The paper has been discredited as bad science, but it got into the public imagination and became a political football when Tony Blair, who had a young child, was asked in the House of Commons: 'Has your child been immunised?' and he wouldn't say,” says Helen Bedford, a professor of children’s health.
Celebrities including Carol Vorderman weighed in on the issue, and “it became a very middle class thing, with people seeking single vaccines,” Professor Bedford told The Independent.
“We're now seeing the legacy of that among all the people who weren't immunised at the time, and are still not immunised – we're seeing measles outbreaks largely in people between 15 and 25.”
Measles, which is extremely contagious and can cause fever, a rash and flu-like symptoms, usually for more than a week, has spread at British music festivals and other large public events. An outbreak was also reported at Disneyland in California.
Spikes in measles infections have also been seen in European countries such as Italy, where the populist Five Star Movement has been blamed for spreading anti-vaccine sentiment.
Mr Wakefield was struck off the medical register in 2010 for acting “dishonestly and irresponsibly” and not in best interests of vulnerable young patients. His research paper has been retracted by the journal after elements of it were found to be falsified.
The 60-year-old now lives in Texas and continues to campaign against vaccines. Last year he wrote and directed a documentary alleging the US Government had covered up a study on autism and the MMR vaccine, which critics have called anti-vaccine propaganda.
Uptake rates of the MMR vaccine is now higher in two year olds than before the controversy, says Professor Bedford, who is a spokesperson for the Royal College of Paediatrics and Child Health. There is no upper age limit to when someone can receive the vaccine on the NHS.
Do vaccines have side-effects?
It’s common to feel tired, sore and as if you’re coming down with a cold after having a vaccination.
This is because the immune system is reacting to the weakened or killed virus contained in the vaccine, which leads to immunisation as the body creates antibodies and becomes able to fight a real infection.
In exceptionally rare cases, vaccines can trigger a serious allergic reaction known as anaphylactic shock. This can develop quickly and is potentially life-threatening, but can be stopped if treated quickly.
Patrick Zuber, group leader of the World Health Organisation (WHO) vaccine safety team, studies the side-effects of vaccinations and publishes information sheets detailing the risks of each one.
“We try to establish the safety profile for each of the known vaccines,” Dr Zuber told The Independent, citing the example of the rotavirus vaccine – shown to cause a treatable condition called intussusception, where the bowel becomes blocked, in one to two cases per 100,000 first doses.
According to the WHO, the vaccine against human papillomavirus (HPV), given to girls to protect against cervical cancer, causes anaphylaxis in around two in a million cases.
After successful worldwide vaccination campaigns, polio is now only endemic in three countries: Pakistan, Afghanistan and Nigeria, with just 37 cases of the disease recorded last year.
Since 2000, nearly three billion children globally have been given more than 10 billion doses of oral polio vaccination, which contains a weakened vaccine-virus that can multiply in the gut, spreading immunity between people.
However on rare occasions, when levels of routine immunisation are poor, it can continue to circulate for a long time. If this is allowed to occur, the vaccine-virus sometimes mutates into a form that can cause paralysis.
In the same time period, 24 outbreaks of vaccine-derived polio were detected in 21 countries, with fewer than 760 cases reported overall. Last year, there were just five cases of vaccine-derived polio in the world, but to prevent any further cases, an injectable vaccine is also being used.
Why are there so many vaccine conspiracy theories?
“A parent with a little worry about immunisation might look for information and find material online that's going to worry them more. There has been research showing that if a parent looks at anti-vaccine material for a few minutes, it can seriously reduce their confidence in immunisation,” says Professor Bedford.
“It's about the potency of social media for some people, and this whole anti-expert environment. Health experts are seen as biased in some way.”
In the UK, “the overwhelming majority of parents are confident in the immunisation programme,” with 93.6 per cent of children receiving their first round of immunisation by their first birthday in 2015-16, according to NHS Digital.
But despite the scientific evidence showing no link to autism, some people are still concerned about the MMR vaccine, says Professor Bedford: “It has the power of anecdotal reports: ‘My child was fine until they had MMR, and then something happened.”
In 2015-16, 91.9 per cent of two-year-olds had received the MMR jab – down from 92.3 per cent in 2014-15 and 92.7 per cent in 2014-14.
Online, anti-vaccine conspiracies range from accusations that vaccination is used for population control to claims that toxins such as mercury have been deliberately and maliciously inserted into vaccine formulas.
“The claims are as fundamental as 'we don't need immunisation'; that control of infectious diseases has come about as a result of better housing and better public health measures,” says Professor Bedford.
“To a certain extent that is true, as major advances in reducing infectious disease were down to those things, but we wouldn't have got rid of smallpox without a vaccination, and you wouldn't even be able to think about getting rid of polio.
“In 1992, when the hepatitis vaccine was introduced, you just look at the graph and the number of notifications just drops completely as soon as the vaccine comes in.
“The anti-vaccine people would say the data is being manipulated and the disease is being called something else. It's hard to argue with those kinds of views where there's no substance to them at all.”
A compound called thimerosal, which contains mercury, is used in the US as a preservative in multi-dose vials of flu vaccines, and in the manufacturing process for two other childhood vaccines. This is because if a vaccine becomes contaminated with bacteria, it can become deadly.
According to the US Food and Drug Association (FDA), in 1999 it was decided that as much mercury as possible should be removed from vaccines as a precautionary measure, despite no evidence thimerosal was harmful for children.
“No childhood vaccine contains [thimerosal] and hasn't done for many years; MMR never contained it as it would kill the viruses. It is still contained in flu vaccines in the US,” says Professor Bedford. “Aluminium is also used to make the vaccine work better, so you need less of the active components. But we eat aluminium, we breathe it, it's in baby milk and deodorant.”
“There are some very vocal, extreme people on the internet saying it's all a conspiracy, run by drug companies, it's about population control,” she says.
“But because vaccines have been so successful, you don't see the diseases any more: you don't see children damaged from polio. You don't hear of hundreds of children dying from measles any more."
Should my child have the HPV vaccine?
Girls aged 12 to 13 are vaccinated against the human papillomavirus (HPV) on the NHS, which protects against cervical cancer – the second most common type of cancer in women under 35.
The vaccine used is called Gardasil, which has been shown to be safe by several studies, some involving more than a million women, that closely monitored side effects and adverse events.
Fears were raised when a 14-year-old girl from Coventry died in 2009 shortly after receiving an HPV vaccine at school. “Jab ‘as deadly as the cancer’,” said the Sunday Express front page, before the cause of her death had been confirmed.
But post-mortem results showed that the girl had a malignant tumour next to her heart that had not been spotted, and her death was unrelated to the vaccine – a fact that generated considerably fewer headlines.
Another article around the HPV vaccine that has since been debunked by fact-checking site Snopes was headlined: “Paediatricians association admits HPV vaccine causes ovarian failure”. This was published on a site called Truth Kings in 2016 and subsequently republished elsewhere.
However, it was the credible-sounding 'American College of Pediatricians', not the well-known and reputable American Academy of Pediatrics, that had made this claim.
Background research by Snopes found that this small, recently-founded group have also said it would be “dangerously irresponsible” to allow same-sex couples to adopt children, and their policy statement on Gardasil had been written from a similarly morality-focussed viewpoint.
The article's headline also exaggerated the contents of the group's statement, which called for more study on a potential connection between the vaccine and ovarian disfunction and did not mention cancer.
The fact remains: More than a decade since the HPV vaccine was introduced in 2006, the number of new cervical cancers has halved.
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