Understanding the MMR

The MMR vaccination has been dogged by controversy. It’s important to understand more about measles, mumps and rubella to address the fear about the vaccination and any other misconceptions there might be.

The diseases.

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, spots in the mouth, followed by a 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 children, and are most serious in under five year olds. 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 children and can lead to deafness, and diarrhoea occurs in 8%.

In 2011 there were 15,800 deaths globally from measles. In the UK since 2006 there have been less than five deaths from measles. Continuing to vaccinate the population is essential to reduce the morbidity rate in the coming years. Prior to the 1980s when the widespread MMR vaccination was introduced, there were an estimated 2.6 million deaths annually.

Mumps can be quite a benign disease in children before puberty. However in boys post puberty it can cause inflammation of the testes (orchitis), which in some cases can lead to sterility.

Rubella is a benign disease for anyone who is not pregnant. However if contracted by women before 20 weeks gestation it can lead to devastating consequences for the fetus, including blindness, deafness and intellectual disabilities.

Vaccination prevents the serious consequences of all three of these diseases.

The vaccination.

Guidelines state that children should receive their first vaccine at one year of age, then the second vaccine (booster) at around three years and four months of age.  

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, 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, there is no evidence for MMR causing autism or gut disease.

Autism is rising and we still do not have any idea about its cause. However, it is important to point out 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.

Egg allergy and MMR vaccination.

There is often confusion about egg allergy in relation to the MMR vaccination. There is only a tiny amount of ovalbumin contained in the vaccine which is extremely unlikely to cause any serious adverse reaction.

In over 99% of all children having the MMR vaccine there are no reported side effects directly related to egg allergy.

Single vaccines.

There are suggestions 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.

Also the efficacy of the single measles vaccine is not as rigorously tested as the combined vaccine. 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.

If you or your child have never had the MMR vaccine or only had one dose it’s not too late to catch up. Treatment is available for children and adults, for more information, visit bupacromwellhospital.com


Dr Michael Markiewicz, Consultant Paediatrician at Bupa Cromwell Hospital.