MMR Vaccine: The Facts all Parents Should Know

Dr Paul Soler MD MRCP

Infections: How Dangerous Are They?

There is general agreement among historians that infectious diseases through the ages have claimed more lives than all the wars put together in the history of mankind. Examples are many. The most destructive epidemic of modern times, the influenza pandemic of 1918, is estimated to have caused over 40 million deaths. Smallpox, a highly contagious viral infection, was a leading cause of death for many centuries, until Edward Jenner in 1796 discovered an effective vaccine for this deadly infection. Well into the late 1960s the World Health Organization (WHO) estimated that approximately 15 million people worldwide contracted smallpox annually, resulting in some 2 million deaths. In 1967 the WHO launched a worldwide vaccination campaign against smallpox and only 12 years later declared that the world was completely free from smallpox. This was an unprecedented declaration, for never had a life threatening infection been globally wiped out by a mass vaccination campaign. And now that we are living in the 21st century, should there still be concern about specific infections such as measles which many parents and grandparents consider an inevitable chapter of their own childhood?

The figures speak for themselves: current estimates by WHO show that up to 2 million children die annually from complications directly related to measles infection alone, the vast majority being normal children unprotected by vaccination. These few examples illustrate the potential magnitude of human suffering caused by infections when medical vigilance and prevention are lax or absent. They also explain why Public Health officials, family doctors and paediatricians put so much emphasis on the need to protect our children from an early age against these potentially disabling and deadly infections.

This article will address two issues: the first is to provide parents with medical data specifically about the Measles/Mumps/Rubella triple vaccine (MMR) based on current scientific knowledge; the second is to comment about some points in the cover story entitled The MMR Debate: science or scaremongering? appearing in the 10th May 2003 issue of The Times, points which were either ambiguous or scientifically and medically unsound.

Parental Concerns and Questions

Fortunately, childhood deaths from measles, mumps and rubella are virtually unheard of in our country. On the other hand, alleged reports in the newspapers of adverse reactions resulting from vaccination are alarming. Parents ask themselves and their doctor many questions: What are these infections anyway? Why should we protect our healthy child against a threat we have never seen or experienced? Why should our healthy 15 month old child be exposed to the potential side effects of a vaccine which has lately been the subject of controversy and debate in the media? How safe and effective is the MMR vaccine? Why not give each component of the vaccine separately? What if we have an older child with autism? And why have some doctors attempted to throw serious doubt about the safety of the MMR vaccine? These are all pertinent questions. The doctors duty is to answer them openly and objectively, applying current medical knowledge to provide factual information in a format which can be understood by the parents. Moreover the doctor must remember at all times that the decision to vaccinate the child lies with the parents, and the doctor must always respect the parents final decision.

The cover story of May 10th presents some of these questions but does not provide tangible answers to the readers. One must also point out that the cover story deals with issues about vaccine safety while omitting important basic information about the dangers of the infections themselves. This approach is lacking in objectivity and is unhelpful to parents seeking the best for their child.

Basic Medical Facts About Measles, Mumps and Rubella

Any discussion about the pros and cons of a specific vaccine must also include the basic medical facts about the related infectious disease. In other words the doctor must weigh the benefits versus the risks of vaccination. This is a fundamental principle of sound medical practice and is applied to all modalities of modern medical management.

Measles is highly infectious and is caused by a virus known to infect only humans. There is no specific cure available for the disease. It is very uncommon in the first year of life. It is frequently a severe infection in childhood, causing a high fever, cough, malaise, red eyes, and an extensive rash over the whole body. Complications are very common and include middle ear infections (7% of cases), croup, bronchitis, pneumonia, acute encephalitis (1 per 1000 cases, a quarter of whom remain permanently mentally disabled). Subacute sclerosing panencephalitis (SSPE) is a very rare complication of measles and is invariably fatal. Despite modern medical care, the overall risk of death from measles is 1 per 1000 cases in developed countries. That is a significant mortality rate.

Mumps is also caused by a virus for which there is no specific treatment. Prior to widespread vaccination, mumps was a common childhood infection. It is very infectious and is transmitted through coughing, sneezing and saliva. The classical manifestation is painful swelling of the parotid salivary glands situated over the jaw close to the ears. Involvement of other organs can occur: neurological complications resulting in severe headache, neck pain, mental confusion, convulsions, facial paralysis, hydrocephalus and problems with co-ordination and balance; painful inflammation of one or both testes (orchitis) occurs in about 20% of infected postpubertal males. Sterility is a rare but a documented complication. It can cause deafness, usually in one ear, at any age.

Rubella is also caused by a virus which infects only humans. Again, there is no specific treatment for the disease. It is transmitted from person to person by direct contact, sneezing and coughing. It is often a mild childhood infection and complications are unusual. It is very rarely fatal. The virus however is extremely dangerous to the fetus in early pregnancy and causes severe congenital malformations when a non-immune pregnant woman contracts the virus. The aim of mass vaccination in childhood is to protect children and the unborn fetus from the damaging effects of the virus.

A common pitfall is for parents to ask about vaccination safety and effectiveness without first asking about the dangers of the infections itself. It is important to stress that when a normal healthy child contracts one of these viral infections, there is no way of predicting how severe the infection will become or which complications will develop. Good health prior to infection is no guarantee of a mild infection with a happy ending.

Moreover, no doctor, regardless of age or experience, can reassure his or her patients that the risk of complications can be ignored or minimized simply because these same complications have gone unnoticed in his or her personal practice. There is no scientific basis for such conclusions and parents should, in the best interests of their child, ignore such remarks and seek the facts from more objective sources.

Safety and Effectiveness of the MMR Vaccine

Of course, the other side of the coin deals with data on the safety and effectiveness of the vaccine. Vaccination safety must always be a prime consideration of medical professionals and parents. There is extensive experience with the use of the MMR vaccine. In USA alone, over 240 million doses of measles vaccine were distributed from 1963 to 1993, and over 70 million MMR doses since 1990. Over 500 million doses of MMR vaccine have been administered worldwide since the mid 1970s. Moreover, it remains the subject of continuing audit and surveillance by leading experts in epidemiology and infectious diseases the world over. Its excellent safety profile is now universally recognised by many authoritative institutions in over 90 countries, including the American Academy of Pediatrics and The Center for Disease Control of the United States, the Joint Committee on Immunisation and Vaccination of the United Kingdom, and the World Health Organistion.

Parents can put their minds at rest that these institutions are not in the pay roll of the manufacturers of the MMR vaccine!

This is not to say that the MMR vaccine is perfectly safe and carries no risks at all. Such claims would be ludicrous. No such treatment exists or will ever exist in an imperfect world. Nothing in life comes without risk. Even a simple bottle feed to a newborn baby carries some risk. Does that mean that we should not bottle feed babies any longer? Current medical data clearly show that the benefits of the MMR vaccine far outweigh the risks of side-effects, and that contracting the wild measles, mumps or rubella viruses is much more likely to result in serious complications for the child.

Parents must also appreciate that no vaccine is ever 100% effective or that the protection it offers is necessarily lifelong. At no time has the medical world made any promises to that effect and any such allegations are unfounded. Current studies show that the MMR vaccine will protect 95% of individuals and that vaccine-induced rubella antibodies will persist for at least 16 years after vaccination. Two doses offer the advantage of increased and longer protection, well into the child-bearing years.

There are several documented adverse reactions associated with the MMR vaccine. Malaise, fever, and a rash may occur about a week after vaccination and lasts only a few days. Some children (1 per 1000) will sustain a febrile convulsion while others (1 per 100) will develop swelling of the parotid gland. All these adverse effects resolve completely without permanent ill effects. Very rarely (1 per 300,000 cases) aseptic meningitis can occur after mumps vaccination. This reaction resolves spontaneously with no permanent ill effects.

MMR Vaccine, Autism and Inflammatory Bowel Disease

In 1998 a study by Dr Wakefield and co-workers of the Royal Free Hospital in London raised the question of an association between the MMR vaccine, autism and inflammatory bowel disease (IBD). This study had a number of serious limitations: it recruited only 12 children, too few to make generalizations about complex diseases like autism and IBD; the researchers also postulated that the MMR vaccine caused IBD which in turn led to autism. However, in some of the children the symptoms of autism actually preceded the onset of IBD. Other larger studies, some involving up to 500 children, found no relationship between the vaccine and autism. Working groups of experts, including the American Academy of Pediatrics, agree that the MMR vaccine is not responsible for the recent increases in the number of children with autism. There is convincing epidemiological and laboratory data which shows no association between the measles vaccine and IBD. In 1998, the Medical Research Council of the UK called together over 30 experts to review all the scientific data and concluded, There is no evidence to indicate any link between MMR vaccination and bowel disease or autism.

Current Recommendations on MMR Vaccination

In the light of current medical evidence, the Maltese Paediatric Association (MPA), a professional body representing over 90% of paediatricians in our country, strongly supports the policy by the Department of Health and the WHO to recommend MMR vaccination for all children aged 12 to 15 months, with a second dose being given at 4 to 5 years. There is insufficient medical data about the safety and effectiveness of single component vaccines, and so the MPA cannot recommend their routine use. Moreover, it must be noted that no country in the world with access to the MMR triple vaccine is using single component vaccines.

Moreover, the MPA affirms that Dr. Anton Mifsuds contribution in the Weekender of the 10th May issue of The Times was made entirely on his own behalf, and in no way does he reflect the opinion or practice of other child specialists on the subject of MMR vaccination. The Association, on behalf its members, strongly refutes Dr. Mifsuds sweeping statement that senior people are not setting the example with their own children. This allegation is entirely inaccurate and completely unfounded. Moreover, there is no scientific basis why Dr. Mifsud is all in favour of rubella vaccination in isolation and against the triple MMR vaccine when the latter has a safety record on par with the former.

As a concluding remark it is fit to quote Professor David Hall, President of the Royal College of Paediatrics and Child health of the United Kingdom: The MMR vaccine was introduced because these diseases can be serious - the supposed link between MMR and autism is completely unsubstantiated whereas there is absolutely no doubt that the diseases themselves can cause brain damage - as I know from my own experience over the past 30 years.