Why does the public still have doubts about MMR?

ON FEBRUARY 2nd, the prestigious UK medical journal, The Lancet, retracted a paper it published in 1998 linking childhood vaccinations…

ON FEBRUARY 2nd, the prestigious UK medical journal, The Lancet,retracted a paper it published in 1998 linking childhood vaccinations to autism. The 1998 paper caused many parents to fear that vaccination would harm their children. Immunisation rates declined with a consequent increase in the incidence of measles, writes WILLIAM REVILLE

The fears about vaccinations are slowly abating, but still remain common. There is a strong medical-scientific consensus that there is no link between vaccination and autism (see British Medical Journal2010; 340: c696)

The principal author on the 1998 Lancetpaper was Dr Andrew Wakefield, a gastroenterologist in London's Royal Free Hospital at the time, and the paper was co-authored by 12 others, 10 of whom withdrew their names before The Lancetretracted the paper. The UK General Medical Council (GMC) declared on January 28th, 2010, that the study reported in the 1998 paper was seriously flawed ethically and, following this judgement, The Lancetretracted the paper. The GMC investigation did not adjudicate on whether the scientific findings of the study were right or wrong, focusing only on the methods used in the study.

The vaccine in question is the combined measles, mumps and rubella (MMR) vaccine, introduced in the late 1980s. The 1998 Lancetpaper reported a study of 12 children with chronic intestinal disorders who had a history of normal development followed by serious mental regression, including cases where onset of mental regression was judged to be soon after administration of MMR vaccine.

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Although the study found no definite link between the vaccine and autism, Wakefield later speculated that the MMR vaccine could cause a chronic measles infection in the intestine that could leak into other parts of the body and damage the brain. He suggested that the “three-in-one” MMR vaccine should be delivered over a longer time in three separate shots.

News of Wakefield’s speculation spread quickly and soon worried parents were avoiding vaccinating their children. The percentage of children in the US not vaccinated with MMR in 1997 was 0.77 per cent. In 2000, this figure had risen to 2.1 per cent. Similar figures were reported in the UK.

The US was declared free of measles in 2000, but there was a measles outbreak in 2008.

There was also an outbreak of measles in Britain and several children died.

Many studies looking for a link between vaccination and autism followed Wakefield’s 1998 paper, but no link was found.

The scientific consensus now is that there is no link between MMR vaccination and autism and the strong medical advice is that children should routinely receive MMR vaccination.

However, many parents still fear the vaccine despite the unambiguous scientific evidence.

In 2006, investigative journalists in Britain charged that Wakefield’s work was partly funded from the Legal Aid Board through a solicitor who hoped to take legal action against the vaccine manufacturer. Also, in 1997 Wakefield applied to patent a new measles vaccine that would become widely used if the MMR vaccine were withdrawn.

The GMC investigation found several medical ethical violations in Wakefield’s study, for example 11 children received unnecessary and invasive procedures such as colonoscopies, lumbar punctures and barium meals. Wakefield also allegedly paid his son’s friends £5 (€5.69) each for blood samples at a birthday party.

Wakefield called the recent findings of the GMC “unjust and unfounded”. He is now director of the Thoughtful House Centre in Austin, Texas, which studies developmental disorders. The GMC is scheduled to decide this April whether Wakefield’s ethical misdemeanours amount to “serious professional misconduct”.

Depending on the verdict, the GMC may decide to reprimand Dr Wakefield or even to revoke his license.

The public no longer automatically trusts the guidance given by official authorities as it did in the past. For example, if medicine introduced a new vaccine for children 50 years ago the vast majority of people would accept it. This new attitude also applies to many other areas apart from medicine – the public is very wary of official reassurances about mobile phone transmission masts, genetically modified food, low level radiation, and so on.

The general principle of authority having to earn public trust is good but problems arise when the advice given by authority is based on sound science but is rejected by many out of fears based on misunderstanding – as in the case of the vaccine fears.

Often these fears are stoked by pressure groups who are pushing an agenda, such as some form of alternative medicine.

The media tends to give all voices equal weight and unjustified fears promoted by amateur groups easily take root in the public mind.


William Reville is UCC’s associate professor of biochemistry and public awareness of science officer at understandingscience.ucc.ie