Figure 1:
Naturally acquired adaptive immunity is generated through natural contact with a pathogen. When the body is exposed to a pathogen it will trigger an immune response, which is mediated by lymphocytes (white blood cells). There are two types of white blood cells important in adaptive immunity: B lymphocytes and T lymphocytes. During an infection by a pathogen, B lymphocytes will be stimulated to produce antibodies that can neutralise the microbes or mark them for destruction. Meanwhile, T lymphocytes will destroy any cells of the body that have been infected by the pathogen. The first time your body encounters a particular microbe, your immune system takes a number of days or even weeks for your body’s B lymphocytes to produce sufficient antibodies or for your body to produce activated T lymphocytes that combat the disease. The pathogen can cause a period of illness before the antibody level in the body is high enough to combat the infection. After the pathogen has been destroyed, most of the antibodies are slowly degraded. However, during the immune response, so-called “memory cells” are also generated. Throughout the lifetime of the person, these cells will “remember” each specific pathogen encountered. This process is called immunological memory. Due the presence of memory cells, reinfection at a later time leads to a rapid increase in antibody production and a much stronger immune response (see figure 1). As a result, later infections can be mild or even inapparent, proving that the body has become immune to that pathogen.
Meanwhile, artificially acquired adaptive immunity develops only through deliberate actions such as vaccination, in which the body is exposed to a weakened, dead or part of a pathogen by injection of a vaccine. Artificially acquired adaptive immunity also results in the formation of immunological memory, but the fact that the pathogen has been weakened means that the recipient of the vaccine does not suffer from the disease in the process (see figure 2), although they may some side effects.
Figure 2:
2.2 What is vaccination?
Vaccination is the administration of an antigenic preparation (vaccine) on a human to stimulate the production of antibodies in their body and provide them with adaptive immunity against disease. Vaccines prevent or reduce the effects of infection by many pathogens. Vaccines can either be administered as live but weakened forms of the pathogens which are being vaccinated against, killed or inactivated forms of these pathogens or purified material such as proteins. However, ‘vaccination’ is not the same as ‘inoculation’, which uses live pathogens, although either is used to refer to an immunisation. Many vaccines have proved to be highly effective, greatly reducing the number of cases of previously dangerous diseases including influenza [8], HPV [9] and chicken pox [10].
The first vaccinations were administered in 1796 by Dr. Edward Jenner, a British physician who tested the possibility of using cowpox as an immunisation for smallpox on an eight-year-old boy named James Phipps after noticing that during an epidemic of smallpox in 1788, milkmaids who suffered from cowpox never attracted smallpox [11]. Smallpox was one of the greatest killers of the time period, particularly in children (300 million people died of smallpox in the 20th century alone), while cowpox was a relatively mild disease. This meant that it was safe for Jenner to take pus from a cowpox pustule and insert it into an incision (cut) on the boy's arm. Jenner subsequently proved that having been inoculated with cowpox, Phipps was immune to smallpox and he went on to publish his discovery in 1798.
Although all vaccinations work by presenting a foreign antigen to the immune system in order to stimulate an immune response, there are several different types of vaccine available. The four main types of vaccine that are currently in clinical use are as follows:
- Inactivated vaccines – these consist of dead microorganisms that cannot replicate, but have intact enough protein shells to be recognised and remembered by the immune system.
- Attenuated vaccines – these contain live microorganisms with very low virulence. They will still be able to reproduce, but only very slowly. Attenuated vaccines cannot be used by immunocompromised individuals (individuals with an impaired immune system).
- Virus-like particle vaccines – these are made of proteins derived from the structural proteins of a virus. These proteins can self-assemble into particles that resemble the virus from which they were derived but lack viral nucleic acid, meaning that they are not infectious.
- Subunit vaccines – these present an antigen to the immune system without introducing viral particles, whole or otherwise. However, subunit vaccines often generate weaker antibody responses than the other types of vaccines.
A number of other vaccine strategies such as DNA vaccination are under experimental investigation. [12] If these are successful, they would offer a number of advantages over conventional vaccines, including the ability to induce a wider range of immune responses.
2.3 What is the MMR vaccine?
The MMR vaccine is a triple immunisation shot against measles, mumps and rubella. It was first developed by Maurice Hilleman in the late 1960s and was first introduced in the UK in 1988. [1][2] The vaccine is a mixture of three live attenuated viruses, administered via injection. The shot is usually given to children around the age of one year, with a second dose when they start primary school. The second dose is not a booster; it is designed to produce immunity in the small number of people (2-5%) who fail to develop measles immunity after the first dose. [13] The second dose is given to everyone because it is impossible to distinguish which children have and which have not been immunised by the first vaccination without putting them at risk.
2.4 What is measles?
Measles is caused by a very infectious virus. Nearly everyone who catches it will have a high fever, a rash and be unwell. Children have to spend about five days in bed and may be off school for twice that. Adults are likely to be ill for longer, although they are less likely to contract the disease. It is not possible to tell who will be seriously affected by measles. The complications of measles affect one in every 15 children. Complications include chest infections, fits, encephalitis (swelling of the brain) and brain damage. In very serious cases, measles can kill. Measles is one of the most infectious diseases known to man. A cough or a sneeze can spread the virus over a wide area as well as leaving it hanging in the air. Because measles is so infectious, it is highly likely that someone who is not protected against it will contract it.
2.5 What is mumps?
Mumps is caused by a virus which causes a fever, a headache and painful, swollen glands in the face, neck and jaw. It can result in permanent deafness, viral meningitis (inflammation of the lining of the brain) and encephalitis. Rarely, it causes painful swelling of the testicles in males and the ovaries in females. Mumps lasts about seven to ten days. Mumps is spread in the same way as measles, although it is much less infectious, being more comparable to flu.
2.6 What is rubella?
Rubella (also known as German measles) is a disease caused by a virus. In children it is usually mild and may go unnoticed. In children it usually only causes a short lived rash, swollen glands and a sore throat. However, rubella is very serious for unborn babies. If a pregnant woman contracts rubella, it can seriously damage her child’s sight, hearing, heart and brain. Rubella infection in the first three months of pregnancy causes damage to the unborn baby in up to nine out of ten cases. This condition is called congenital rubella syndrome (CRS). In many cases, pregnant women catch rubella from their own or their friends’ children. Rubella is spread in the same way as measles and mumps, although it is the least infectious of the three diseases.
2.7 What are autism and Crohn’s disease?
Autism is a terminal and incurable disease in which children’s behaviour and learning ability is affected, while Crohn’s disease is an inflammatory bowel disease.
3. ARGUMENTS FOR
3.1 Immunity
The strongest argument for making the MMR vaccination compulsory in the UK is that it would protect all individuals who were vaccinated from suffering from measles, mumps or rubella. These diseases are sometimes perceived as relatively mild childhood illnesses. However, the reality is quite different. There is a 0.3% death rate associated with contracting measles in more economically developed countries, with this figure rising up to 28% in poorer countries [14]. The complications of measles include diarrhoea, pneumonia and encephalitis, with 1 in every 15 children contracting the disease being seriously affected [2]. Similarly, mumps can result in permanent deafness, meningitis and encephalitis. Rubella infection in the first 3 months of pregnancies will damage the unborn child in 9 out of 10 cases [15]. Even though vaccinations can have adverse side effects, such effects are significantly more common following the natural disease. It is the responsibility of the government to protect its citizens from these preventable ailments, particularly the country’s children. It should therefore make the MMR vaccination compulsory in the UK.
3.2 Herd immunity
It is important that all children are vaccinated not only to protect themselves, but also to ensure herd immunity. Herd immunity is when a high enough percentage of the population (this needs to be about 95%) is vaccinated that even those who have not been given the vaccine are protected by the fact that diseases cannot spread. As no vaccine is fully effective, it is inevitable that some people will not become immune against the disease. Therefore, as a direct result of the drop in MMR vaccinations (see figure 3), epidemics can happen again as has been the case in 2003 and 2008 (see figure 4). If enough people are vaccinated, epidemics cannot occur, an effect known as “herd immunity”.
Figure 3: Figure 4:
3.3 Safety record
Another reason for making the MMR vaccination compulsory in the UK is the excellent safety record that the triple vaccine has built up over time. Worldwide, more than 500 million doses of the MMR vaccine have been given in over 100 countries, [2] with no safety concerns. The World Health Organisation regards the vaccines safety as “exemplary”. [16]
3.4 Practicality
Furthermore, the 3 in 1 vaccine is an efficient way of ensuring protection to 3 independent diseases. It is cheaper and easier to administer the vaccine as one injection rather than as three separate doses, which also saves doctors and nurses a lot of time. Also, the triple vaccine is more effective than single vaccines as illustrated by the drop in measles infection after the introduction of the triple vaccine (see figure 5). In fact, the triple MMR vaccine is now also available as a quadruple MMRV vaccine, which also immunises against varicella (chickenpox). [17] This is being increasingly administered in other countries such as the USA and Australia, so we should do the same here.
Figure 5:
3.5 Eradication
Finally, by making the vaccines compulsory in the UK it may eventually be possible to eradicate the three diseases altogether. Although this would be a long-term goal, people have demonstrated that it would be possible through worldwide vaccination programmes, as smallpox, another viral disease, was eradicated in this way.
4. ARGUMENTS AGAINST
4.1 Side effects
Although the safety record of the MMR vaccination is good, it is impossible to predict an individual’s immune response to it. In rare cases, the vaccine has had serious side effects on its patients and as a result, no individual should be forced to be vaccinated.
4.2 Civil rights
Further supporting the argument of not making the MMR vaccination compulsory in the UK are our civil rights, which we value greatly in our country. By law, everyone in the UK has the right not to act against their will as well as the right to choose how to treat their own body [18]. The government is therefore not entitled to legislate that the MMR vaccination should be made compulsory.
4.3 Fears over autism and Crohn’s disease
Another argument against the MMR vaccination that has had a greater effect than anything else is doubt surrounding potential unknown side effects of the vaccine. In 1998, a scientist called Dr. Andrew Wakefield published a paper in the well respected scientific journal, The Lancet, in which he claimed to have found a correlation between the MMR vaccination and an increased risk of autism and Crohn’s disease (see figure 6), saying that MMR could be “causing 1 in 10 cases of autism.” [19] However, these claims were very controversial as they lacked sufficient evidence to support them. Although there was an increase in the number of reported people with autism after the introduction of the MMR vaccine, Wakefield misinterpreted the data because this rise was in fact due to recent medical improvements meaning that autism could be more easily diagnosed. The number of people who actually had autism did not change.
Nevertheless, these studies have highlighted the uncertainties associated with any vaccination, leaving many parents anxious about the MMR vaccine. Why should parents be forced to have their children vaccinated when there is a potential risk of inducing serious ailments in their child, especially as the benefit of the vaccine to the individual child is smaller when the majority of children have been vaccinated? It is up to parents not the government to make a decision that they believe is in the best interest of their child.
Figure 6:
This graph shows the basis for Andrew Wakefield’s claims
4.4 Single vaccines
It has been argued that even if the Government believes MMR to be safe, they should still provide single vaccines because then more children would be vaccinated. However, there is no evidence to support the suggestion that allowing single vaccines would lead to a greater uptake of MMR. Single vaccines would be less effective and there is no evidence that they would be safer. Problems associated with single jabs include:
- Delays – these would be an inescapable part of a single vaccine strategy. More children would be left unprotected for longer, with more opportunity for dangerous vaccines to spread
- Missed appointments – over 11 million GP appointments and over 5 million practise nurse appointments are missed every year in the UK. [20] Single vaccine strategy would require six separate vaccinations (two for each disease) instead of two triple vaccinations. This is bound to cause more missed appointments and lead to reduced protection against disease.
- Not taking up rubella vaccination – parents may opt not to vaccinate their children, particularly their sons, against rubella as they feel that they are at less risk from it. In fact, unvaccinated boys can catch rubella without knowing and go on to infect pregnant women, including their own mothers.
Offering single vaccines could also reduce confidence in the vaccination program, which in turn could lead to reduced uptake, putting people at risk.
4.5 Cost
Furthermore, parents argue that the government could save the NHS money by keeping the MMR vaccination optional. However, this does not take into account the cost of treating children suffering from the diseases, which is why some people argue that making the vaccination compulsory would actually be cheaper.
4.6 Unnatural
We must also consider the religious reasons why people may not want to be vaccinated. The MMR vaccine is man-made and could therefore be seen as interfering with nature, even if it does benefit humans. Others might take this point even further, arguing that if God intended us to suffer from these diseases, we should suffer from these diseases and that therefore, the vaccine should be banned altogether.
5. IS MORE RESEARCH THE ANSWER?
Many parents who find themselves unable to make a decision on whether or not to have their children vaccinated against MMR have called for more research to be undertaken to give them a better understanding of its safety. However, there is already a large body of evidence suggesting that there is no link between MMR and autism or Crohn’s disease, and the number of studies demonstrating this is growing. For example:
- A 2002 study, with a sample population of virtually all the children born in Denmark over almost ten years, found no evidence that there was more autism in children who had received MMR than in the non-vaccinated children. [21] This study collected vaccine records and autism diagnoses separately, meaning that there could be no ‘recall bias’ from parents looking for a reason for an autism diagnosis. In addition to this, there was no association between the age at vaccination, the time since vaccination or the date of vaccination and the development of autism. The Danish study concluded that: “this study provides strong evidence against the hypothesis that MMR vaccination causes autism”.
- In 2005, researchers from the Cochrane Collaboration reviewed 139 studies conducted to assess the effects of the live attenuated combined vaccine to prevent measles, mumps and rubella in children. [22] No credible evidence of an involvement of MMR with either autism or Crohn’s disease was found.
- A more recent study, published in July 2006, showed that autism rates in Canada continued to rise even though MMR coverage was falling. [23] The study concluded that apparent increases in autism in recent births cohorts, as found in many countries, was due to better awareness and improved diagnosis of autism. The number of people with autism did not actually change.
So while more research can always be done, it would be unnecessary as there is already a huge body of highly credible evidence from around the world supporting the safety of MMR. Some people will always be suspicious of scientific, medical and political authority, and this is not helped by the way in which some sections of the media provide coverage of MMR as though opinion were equally divided about its safety.
6. CONCLUSION
In my opinion, the MMR vaccination should be made compulsory in the UK because it would be the most effective way of increasing the uptake of the vaccine to over 95% of the population, ensuring that society would benefit from herd immunity. However, I understand that many people who are still wary about the risk involved in being vaccinated would object to this legislation as an infringement of their civil rights, arguing that they should be allowed to make their own decisions on the treatment of their own bodies.
Therefore, I think it would be more reasonable to require children to be vaccinated in order to be admitted to school. This way, the vaccination is not completely compulsory, meaning that those who have particularly strong views against having their children vaccinated could have them educated at home. Nevertheless, this policy would still ensure that a high enough percentage of the population is immunised in order to make the vaccination effective because very few people would be prepared to withdraw their children from school just because they had concerns regarding the safety of the vaccine. This system is already in place in other countries such as the USA and Australia and has proved to be very successful. In the United States, fewer than 200 cases of measles have been reported each year since 1997 and the disease is no longer considered endemic. [24][25][26]
Despite this, the government shows no sign of changing its policy and it continues to promote vaccine uptake for all children who are able to receive vaccinations on a voluntary basis.
7. BIBLIOGRAPHY
Below is a list of sources that I have referred to throughout my case study. I have detailed the full URLs of these websites and the full titles of any books used in my research.
[1] Offit P.A., One Man’s Quest to Defeat the World’s Deadliest Diseases. 2007.
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19] Meikle J., MMR “may cause 1 in 10 cases of autism”, in The Guardian. 2002.
[20] Developing Patient Partnerships (DPP) and the Institute of Healthcare Management (2006)
[21]
[22]
[23]
[24]
[25]
[26]
