PEPs - Clinical Quality and Evidence

Module 2 - Evidence

Example - Vaccines

Image by CDC on Flickr

Many years ago vaccination seemed very simple. Vaccines were introduced and the diseases which were the scourge of childhood were conquered, one by one. So smallpox and polio were conquered. Then measles was taken out and more recently the combined vaccine of mumps, measles and rubella (MMR) has neutralised mumps and rubella with their serious sequelae. Most recently, vaccines have been developed for meningitis and pneumococcus, and also a vaccine has been introduced to deal with papilloma virus – even cervical cancer will, possibly, be under control. We also had BCG which has an important place in public health. It is likely that most of the early vaccines were introduced somewhat like penicillin, without a double blind trial. There was a dire disease, killing or maiming lots of children which were tamed, for everyone to see, by a simple treatment.

There has, however, always been some scepticism regarding vaccines. This came to a head with the publication of a paper in 1998 in the Lancet by Andrew Wakefield and colleagues, alleging that the MMR vaccine was responsible for some cases of inflammatory bowel disease and autism ¹ .  The paper was a case series of 12 child patients - basically a collection of clinical anecdotes or descriptions of individual patients. Such a study could not demonstrate a relationship between an exposure (e.g., MMR) and an outcome (e.g., autism) with any force. A large-scale epidemiological study was published soon afterwards that found no evidence for a causal association between the MMR vaccine and autism ² .  The debate revolves round whether an event such as a vaccination can be accused of causing an illness that occurs sporadically and might have occurred with or without the temporal association of a vaccination. This has now gone full cycle with an investigation by Brian Deer in the Sunday Times in 2004 suggesting that Wakefield had a financial conflict of interest. This eventually led to a GMC enquiry where Wakefield was struck off the medical register and the Lancet withdrew the paper.

The irony is that if you search YouTube for vaccinations there are pages of videos arguing against vaccinations. The first clip is lead by a doctor and the other two show politicians and parents. There is no doubt that the debate continues on irrespective of the science (which consistently shows no evidence of a link between MMR and autism). It is interesting that there is no mainstream defence of vaccination on YouTube. Please review the original paper and see what conclusion you would have come to if you had read it at the time. What other sources of information might you have sought to check the validity of this paper?

Teacher's Comment

How would you have dealt with distraught parents wishing to know what to do?

Please read the following article:

Attachment: The pertussis vaccine controversy in Great Britain.pdf

The pertussis vaccine controversy in Great Britain, 1974–1986 - Baker, J.P. (2003) Vaccine 21 4003-4010

Also watch the following videos on YouTube and think how you would deal with parents who have watched these.

1. Suzanne Humphries on Vaccines

2. Congressman Elijah Cummings questions vaccine policy in autism hearings

  1. Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children - Wakefield et al (1998) The Lancet 351 637- 641 (PDF) Paper retracted following the judgment of the UK General Medical Council's Fitness to Practise Panel on Jan 28 2010
  2. Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association - Taylor et al. (1999) The Lancet 353 2026-2029.