News and Views: The importance of vaccination

There has been a story in the news recently about a measles outbreak in Swansea and certain other areas of Wales. The cause of this outbreak is attributed to a lack of children being vaccinated with the controversial Measles, Mumps and Rubella (MMR) jab. This measles outbreak highlights the troubled relationship between the general public and vaccination.

The drop in numbers of children receiving the MMR jab can probably be traced back to a 1998 news story. A paper was published in the journal The Lancet stating there was a link between the MMR jab and cases of autism and bowel disease. The study was led by Andrew Wakefield, a former surgeon. Wakefield claimed that instead of the single MMR jab, a vaccination should be administered in three single doses, one for each disease.

However, there were several major problems with the science in the paper. No other scientists could identify the link between the MMR jab and autism that Wakefield and his team claimed. Investigation by the journalist Brian Deer also revealed that Wakefield had a “conflict of interest”, in that he was being paid by a law firm trying to prove that the MMR jab was harmful. This should have been declared to the Lancet, but wasn’t. Therefore his motives appeared to be more financial than scientific¹. Eventually after a large, long hearing Wakefield was struck off the medical register in 2010.

A greater problem has arisen from all this. However dishonestly Wakefield behaved, his original claim was never that “all vaccinations are bad”. He claimed that one particular vaccine had a (disproven) link to disease.  However, it appears that some people have become generally mistrustful of all vaccines and worry that they all cause serious disease.  For example Michele Bachmann, a US congresswoman contending for the Republican nomination for president in 2012, claimed that the HPV vaccine led to mental retardation. This statement was not based on scientific evidence or due to any research on the HPV vaccine; she was quoting a parent who had also made that claim without any actual evidence. Other people, including celebrities, both here and abroad, have begun to claim links between some vaccines and diseases which have never been scientifically proven. This had led to a multitude of preventable illnesses and deaths because people are unsure about whether to be vaccinated or not.

Can vaccines be harmful? They do sometimes contain “attenuated” or less virulent versions of the disease-causing microbe to stimulate the immune system. This could theoretically lead to a person who is vaccinated getting the disease instead if the virus reverts to virulence. However, vaccines are rigorously tested before being administered, so any side effects can be detected and assessed before it enters the general population. If the side effects are too bad or the vaccine is not effective enough, it will not be administered. Occasionally things can go wrong, but the prevention of these diseases generally outweighs the risks of using the vaccine.

The media has apparently made little attempt to rectify the public’s mistrust in vaccines. Whilst the original story about the link between MMR and autism was blasted across the front pages of the national papers, the subsequent retraction of the paper (in 2010) and Wakefield’s dismissal have not been as heavily reported. This means that people still have a vague remembrance that “vaccinations are bad” and are not being vaccinated because the story has been poorly clarified. Unfortunately, this has led to several outbreaks of measles, as well as other diseases such as whooping cough that can be prevented by vaccination.

It is important that as many people get vaccinated as possible. When enough of the population is vaccinated against a certain disease, the spread of that disease is limited. This protects people that have not, or cannot, be vaccinated. This concept is known as “herd immunity” but, for it to be successful, a large number of the population need to be vaccinated. This is called the “herd immunity threshold” and may need to be up to 95% of the population to be effective.

I’m not suggesting that you should get every vaccine which is available. However, if you or someone you know is due to have a vaccine and you’re worried, ask your doctor (and get second opinions) about potential side effects or the importance of the vaccine. It is important to make an informed decision about whether to be vaccinated or not based on scientific and medical evidence rather than hysterical celebrities or a retracted paper.

¹ Reference: http://www.bmj.com/content/342/bmj.c5347 and references therein

Post by: Louise Walker