Content:

Introduction
What is vaccination?
What does the MMR vaccination consist of?
How are they developed?
Reasons for MMR vaccine
Reasons against MMR vaccine 
Conclusion 
Reference

Introduction

A vaccine is a substance that stimulates the body's immune response. the purpose of vaccination is to prevent or control an infection. Vaccinations make use of the body’s own defence system. They kick-start your white blood cells into making antibodies against specific viruses or strains of a virus. The antibodies persist in your system for years, and you become immune to a disease without having to catch it first. 
The MMR vaccine protects against mumps, measles and rubella, and consists of live viruses that have been weakened so that the vaccine is still capable of including a productive immune response but does cause the disease that the original viruses cause. Mumps is a viral infection of the parotid salivary glands. These glands are located just below and in front of the ears. They produce saliva, which drains into the mouth and helps to break up and digest food. Rubella (German measles) is a very infectious viral illness. The virus is passed on through droplets in the air from the coughs and sneezes of infected people. Measles is a highly infectious viral illness. The illness causes a range of symptoms including fever, coughing, and distinctive red-brown spots. Mostly these infections are temporary and not serious, but if the patient is very young or even not born yet, there is a higher risk of serious harm.

Dead or inactive forms of virus are used in vaccines so you don’t get the disease itself. Sometimes just parts of the virus are used. Vaccines are developed after rigorous testing for effectiveness and safety. A vaccine must be of the proper dose and chemical characteristics to stimulate protective immunity. 

Reasons for MMR:

There is little debate over the need for vaccination. It has cut the numbers of deaths and infections from infectious diseases to virtually zero. Over this specific vaccination – MMR – there is much debate. There is big debate over whether or not it is cost effective to use the MMR vaccine. The triple vaccine is virtually 100% effective and makes it easier and quicker to be vaccinated. People are more likely to complete a course of treatment via the MMR vaccine than if they were to receive three separate vaccines and possibly booster injections. One the other hand doubts have been raised over it’s safety, because of some supposed link with autism in children who have had the vaccination. Some parents say they would prefer the single vaccines to be used, and campaign to be given the option.

Disadvantages of triple vaccines: 

Different vaccines may interact with each other in unpredictable ways. At one stage in 2003 there was a five fold increase in cases of meningitis casused by the Hib virus. It was found that the Hib vaccine had interacted with the whooping cough vaccine to produce vaccine failure. Maybe the immune system had been overworked,  with the immune system being weakened in responding to one vaccine so it could not respond to the other, or maybe the two vaccines had interacted chemically. Could the different vaccines in the MMR jab be interacting in some way to cause autism?

Anthony Harden, a lecturer in general practise at Oxford University and an author of the jama study, said “these combination vaccines are potentially a problem. It seems to be completely unpredictable which combinations cause reductions in immunity. The only way to find out is to do a full scale trial with thousands or even millions of patients.” 
	
A trial of this sort would take years, during which many parents would feel that their children would be subject to medical experiments if the MMR jab  were used on them.

To summarise

1	If you’re vaccinated against three infections at once your immune system may be overworked or confused or the vaccines may interact in some way. Many people say this is a cause of autism.

2	People are more reluctant to allow their children to take the triple vaccine since this controversy started.

3	The triple vaccine is necessarily more complicated than the single vaccines, so if there are side effects it might be hard to determine the cause.

Is there positive correlation between MMR vaccination and autism?

Most studies have found out there is no correlation. Those that question this lack of correlation are either discredited or present very little or inclusive evidence. In particular the first study was based only on 12 children, but to be reliable a study of this should be based on thousands or hundreds of thousands of children. The theory that MMR overloads the immune system thus making them susceptible to ASD has itself being the subject of much controversy and has no intuitive basis. Despite this giving the vaccines as single vaccines might seem a sensible precaution and would reassure many. Why is this not done? 

There is no positive correlation 

No link has ever been found between MMR and autism. Any suggestion of a link is discredited: even the original study which started the controversy stated ‘we did not prove an association between measles, mumps and rubella vaccine and the syndrome described’. The controversy only arose because of a suggestion of the authors that parents should be able to chose between the single vaccine and the triple vaccine. 

A study found by Kaya Et Al, says there was a significant increase in reported cases of ASD – Autistic Spectrum Disorder - in the UK between the periods of 1988 and 1999. However, the rate of the triple vaccine remained equal all through out this period. He concluded that the increase in ASD cases could not be explained by the exposure to MMR. Another, by Dales Et Al, compared the numbers of cases of ASD with rates of the triple vaccine in California, 1980 to 1994. In those periods they found a great increase in the frequency of ASD, but only a little increase in the triple vaccination rates. Additionally, before the small increase in the triple vaccination rates, the incidence of ASD had increased. 

The whooping cough story

Increa There have been similar scares.
In the mid-70s Dr John Wilson, published a statement based on a small group of 36 patients signifying that the whooping cough vaccine might cause brain damage in a minority of children. The number of children being vaccinated against whooping cough fell from over 80% to below 50%. Parents panicked and refused to have their children immunised. It took until the 1990s for the levels of vaccination to steadily elevate again to a level which meant the population is protected by herd immunity. 

Unfortunately, in their fear of the vaccine the public forgot that whooping cough itself causes both brain damage and death. In Scotland alone, 100,000 children suffered from whooping cough between 1977 and 1991 and about 75 of them died. The same matter was seen across the UK. Also, when the original research was looked into, it was found to have serious errors.

No vaccine has ever been entirely secure, but when claims for compensation were brought up to court the whole study was discredited. The judge stated clearly that the risks of whooping cough had outweighed any possible damage caused by the vaccine itself, and he severely disapproves of the scientist and the study which was brought up. Lord Justice Stuart-Smith, the judge who heard the case in court with 19 expert witnesses, concluded, 

‘When I embarked on consideration of the preliminary issue, I was impressed by the case reports and what was evidently a widely held belief that the vaccine could, albeit rarely, cause permanent brain damage. I was ready to accept that this belief was well founded. But over the weeks that I have listened to and examined the evidence and arguments I have become more and more doubtful that this so. I have now come to the clear conclusion that the plaintiff fails to satisfy me on the balance of probability that pertussis vaccine can cause permanent brain damage in young children.

Nevertheless, this judgement got moderately little media coverage. Furthermore, many parents felt there was ‘no smoke, without fire’ so it took up to 20 years before vaccination levels of whooping cough, returned to the levels before the panic. 

Reference:
http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=255
http://www.nhsdirect.nhs.uk/articles/article.aspx?articleID=327
http://www.answers.com/topic/mmr-vaccine?cat=health
http://www.mmrthefacts.nhs.uk/questions/question.php?id=83