Dr Michael Markiewicz BSc MB BS FRCP(UK) FRCPCH is a paediatrician at Chelsea and Westminster Hospital.
The MMR vaccination has been dogged by controversy. In order to address the fear that the public holds about the vaccination and any other misconceptions there might be, we need to learn the background to the diseases. Fully understanding these enables us to reassure parents and immunise patients with no doubts as to the benefits and possible side effects.
Measles, together with chicken pox, is amongst the most infectious diseases in the western world; incubation is about 10-12 days having been spread by fine droplets.
The main features of measles include a high fever lasting about seven days, Koplik spots in the mouth, followed by a very florid rash covering the face and trunk and extending to the hands and feet (which appears two to four days after the fever starts). The rash lasts about five to six days and is often accompanied by coughing, catarrh and conjunctivitis.
Complications are common, affecting up to 30% of otherwise healthy patients, and are most serious in children under five years old. Pneumonia is a common complication and this is also the most common cause of death in young children. In addition, ear infection occurs in 10% of patients and can lead to deafness, diarrhoea occurs in 8%, 1 in 1000 get encephalitis, and for patients with vitamin A deficiency blindness is a common complication.
In 2011 there were 15,800 deaths globally from measles. Prior to the 1980’s when widespread MMR vaccination was introduced however, there were an estimated 2.6 million deaths annually. The death rate in the developing world ranges from 5-28%. In the developed world it is 0.3 %.
Mumps can be quite a benign disease in pre-pubertal children, however in post pubertal boys it can cause orchitis, which in some cases can lead to sterility. This does not apply to girls.
Rubella is a benign disease for anyone NOT pregnant, however if contracted by women before 20 weeks gestation it can lead to devastating consequences for the fetus, causing blindness, deafness and mental retardation.
Vaccination prevents the serious consequences of all three of these diseases.
The usual routine in the UK (unless an epidemic is unleashed) is to give the child the first vaccine at one year and the booster at four years. In some countries the schedule is more aggressive, with the first shot given at nine months, followed by two more vaccines at 18 months and at school entry.
Why the need to give a booster? In 5-10% of children the initial vaccination does not lead to adequate antibody production. In those children who then receive a second dose, well over 90% produce an adequate response the second time around. There are no significant side effects for those children receiving a second dose who have had an adequate response the first time around.
Regarding the supposed dangers of the vaccination, Andrew Wakefield has single-handedly contributed more to the morbidity associated with measles in this country than any other individual. His ill-fated publication in the Lancet in 1988 (based on a total of only 12 self-selected patients) suggested a link between the MMR vaccine and autism as well as bowel disease. This article was later declared fraudulent and retracted, and Andrew Wakefield was struck off the medical register, but the damage was done and we are still reeling from the consequences. There is no evidence for MMR causing autism or gut disease.
What can you do to reassure patients?
There is not one article published in any peer-reviewed journal that suggests a real link between the MMR vaccine and autism. There are however a large number of publications that show no such link exists between the MMR and autism.
Yes, autism is still rising and we still do not have any idea about its cause. However, it is very important to point out to patients that autism is often diagnosed around the same time that the MMR vaccine is administered, and it stands to reason that with over 600,000 doses of MMR given annually in the UK, there will be a incidental time similarity between the administration of MMR and the diagnosis of autism.
No-one has as yet demonstrated any causality between the MMR and autism. Indeed if one looks at the graph of incidence of autism against time it is a steadily rising line. MMR vaccination was introduced in the USA in the late 1970’s and in the UK in the mid 80’s. There was absolutely no change in the incidence of autism in either country after the respective introduction of the vaccine. In both countries the incidence continues to increase at exactly the same rate as before the introduction of the vaccination programs.
Egg Allergy and MMR vaccination
There is often confusion about egg allergy in relation to the MMR vaccination. The amount of ovalbumin contained in the vaccine is in the order of picograms; this tiny amount is extremely unlikely to cause any serious adverse reaction. Gelatin and Neomycin are much more likely candidates in the event of an allergic reaction.
In over 99% of all children having the MMR vaccine there are no reported side effects directly related to egg allergy. However, the recommendation for children who have had anaphylactic or very serious reactions to egg (or those with chronic active asthma and significant reactions to ingested egg such as urticaria) is to administer the vaccine under hospital supervision with appropriate resuscitation facilities available.
The most recent edition of the NHS ‘Green Book’ (Immunisation Against Infectious Disease) goes as far as suggesting that unless there is an anaphylactic reaction to eggs, MMR vaccinations are safe to be carried out in GP surgeries. I concur with that but hope that it does not deter some patients from receiving the vaccine because of unfounded fears of its safety.
As a result of the Wakefield myth the completely illogical suggestion was made that it would be much better to use the single component vaccines.
What is wrong with this approach? The argument that the ‘body can’t cope’ with too many vaccines at once is completely erroneous and again has no scientific basis. In fact, studies that looked at exposure to antibody-producing antigen found that prior to the introduction of more modern vaccines, such as the MMR, antigen exposure was much higher. In addition, they did not find any correlation between antigen exposure and autism or any other adverse effects.
Furthermore, the efficacy of the single measles vaccine is not as rigorously tested as the combined vaccine, and there is a worldwide shortage of the single mumps vaccine (so anyone going down this route will remain un-immunised for mumps). Finally, due to the much longer time taken to complete the process of single component vaccines, the child will remain at risk of disease for much longer.
It is vital to achieve at least a 95% take-up of the vaccine to ensure the safety of our children. By educating your patients we will be able to achieve that goal.