Vaccination

Why is Vaccination so Important?

Vaccination saves lives!

The human immune system is fundamental to maintaining health as it is trained to resist and fight off disease causing bacteria and viruses. At every moment there are swathes of hostile bacteria, fungi and viruses which swarm on our body. Yet we are able to remain relatively healthy – most of the time. Our immune system is uniquely able to provide immunity against pathology-causing organisms, or pathogens. Certain pathogens are so virulent, however, that our immune system cannot provide immunity quick enough before the disease causes long term impairments or death. This is where vaccinations become so overwhelmingly critical, not only to individual health but to the health of entire populations.

A macrophage hard at work keeping the body safe from foreign substances.In brevity let us firstly consider the composition and basic physiology of the immune system: The Innate Immune System:

Composed of two separate divisions which complement each other the immune system is able to provide a complete defense structure. The innate division of the immune system is sometimes referred to as the non-specific immune system since it does discriminate on what foreign substances it protects against. Elements of the innate immune system essentially protect against all foreign substances, pathogenic organisms included. There are two divisions of the innate immune system – the first line of defence is the skin and mucosae (internal linings of mouth, nose, gastrointestinal tract etc). Secondly, there are a number of immune cells which circulate the body through the blood and lymph. The main immune cell which we shall focus on is the macrophage. Macrophages move throughout the body and essentially engulf foreign substances such as bacteria in a process called phagocytosis. Macrophages will only protect against foreign substances such as bacteria if they by chance happen to encounter them on their travels. They cannot actively seek out foreign substances in order to attack them – at least not without the help from other immune system elements.

A macrophage (red) engulfs a tuberculosis myobacterium (yellow)

If a bacteria penetrates the first line of defence and moves into the body encountered by cells of the innate immune system such as the macrophage, the bacteria is able to take hold of the host by reproducing constantly. As this happens the infected host begins to show symptoms of the disease that that bacteria causes. There are certain virulent bacteria and viruses that cause diseases that our immune system cannot respond effectively enough and in enough time to prevent long term damage or death. In such circumstances, our immune system may be helped by other components of the immune system now to be discussed.

Viruses and bacteria are the main disease causing organisms.The Adaptive immune System:

The second major division of the immune system – the adaptive immune system plays a significant role in long term immunity. This is where vaccination plays an important part. The adaptive immune system is quite complex and involves a wide variety of components, however, this article will attempt to address the concept simply. The adaptive immune system, as its name suggests, is able to adapt in response to certain foreign organisms such as bacteria and viruses that it has previously encountered. It is also called the specific immune system since many of the components of this system discriminate in terms of what they attack.

Antibodies have attached to a pathogen and have neutralised it. Now macrophages or T lymphocytes may come and kill the pathogen.

Humoral Division:

The adaptive immune system is further divided into subsections. The Humoral division of the adaptive immune system is concerned with the production of antibodies. Antibodies are Y shaped proteins which circulate through the body’s humor or fluids (Blood and lymph) and neutralize foreign substances. Every antibody has a unique target which is present on the invading organism or pathogen. This target is known as the antigen (Anti-body Generating). The interaction between an antibody and antigen can best be described like a lock and key. When the key inserts into the lock the antibody activates and the pathogen is neutralised. Antibodies do not eliminate the pathogen but neutralising them makes them available to other components which effectively kills and destroy the invading pathogen.

Antibody production:

Antibodies are produced within a special cell called the B lymphocyte or simply the B cell. On the first exposure to a certain foreign organism the B cell is said to be inactive. It does not begin to produce antibodies until it has encountered the foreign organism for the first time in a process called ‘differentiation’. Once the B cell is activated it produces many of these specific antibodies which seek out the specific foreign substance and neutralise it. When activated, some B cells become ‘memory B cells’ which are long living cells which become important on re-exposure to that specific organism at a later time.

Antibodies have attached to a pathogen and have neutralised it. Now macrophages or T lymphocytes may come and kill the pathogen.

On the second and subsequent exposures the memory B cell, already differentiated, instantly begins to produce antibodies and therefore your immune system is able to effectively defend against the foreign organism. In this scenario there is no delay period where the differentiation process has to occur and therefore with the much higher numbers of antibodies circulating the blood, coupled with the greatly reduced time the organism has to reproduce an take hold, our immune system will either completely prevent the disease progressing to show symptoms or will minimise the severity and length of time of the symptoms.

The problem with aggressive bacteria and viruses is that they may cause irreparable damage or death before our immune system can establish an effective defence against it. This is where the importance of vaccination is emphasised – by artificially installing a memory into out immune system of how to combat a specific organism, on exposure to the organism our immune system can act before the disease progresses.

B cells produce antibodies which circulate through the blood and neutralise pathogens.Vaccination is essentially a way of manipulating the immune system to create protection against a disease-causing pathogen without causing the disease within the person. There are a number of ways a vaccination may be created:

Killed or Inactive Viruses: This method is used primarily for viruses and involves treating the virus with heat or chemicals to ensure it is no longer infectious. These vaccines cause a significant antibody response and therefore create immunity through differentiating B cells so that memory B cells are available to ramp up antibody production on subsequent re-exposure to the pathogen.

Attenuated Pathogens: This method involves taking a disease causing organism and growing it in cells of other species so that the organism adapts to that species and therefore grows poorly in human cells. When the vaccine is introduced into humans our immune system will effectively remember how it defeated the pathogen on re-exposure.

Toxoids: Some pathogens cause disease by releasing toxins into the body. This method induces immunity by vaccinating specifically against the toxin. It therefore prevents disease when a pathogen releases toxin in the body.

Antibodies have attached to a pathogen and have neutralised it. Now macrophages or T lymphocytes may come and kill the pathogen.

The processes of creating these vaccines by using various chemical compounds is the argument that anti-vaxers mostly use to whip up hysteria over the dangers of vaccination. They’ll attempt to argue that neomycin and polymyxinB cause kidney damage and that streptomycin prevents protein synthesis and causes hearing loss. This is all true, however the age old saying ‘it’s the dosage that makes the poison’ continues to hold true. If anti-vaxers were in anyway educated on the processes of the human body then they would understand the flaws of their argument.

The DPT Vaccine:

Let us take the process of creating the diphtheria vaccine (usually administered as DPT for Diphtheria, Pertussis and Tetanus) for example: The process involves inactivating the Corynebacterium diphtheria pathogen using formaldehyde. Formaldehyde may be a toxic chemical, however the term toxic is misleading and overtly ambiguous. At high doses formaldehyde is toxic, however, the amount found in the DPT vaccine is so small it simply isn’t an issue. During normal body processes alone your body is generating and breaking down more formaldehyde than what is found in the DPT vaccine. In greater concentration many foods, including meat and fruit contain either formaldehyde or compounds which convert to formaldehyde in your body. An average adult contains about 2.5 micrograms of formaldehyde per millilitre of blood– that’s more than 10 times the amount more formaldehyde than the DPT vaccine contains.

Mercury is toxic in large doses. The insignificant amount which was once found in vaccines was not enough to be toxic.Neurotoxicity of Vaccines:

Furthermore, anti-vaxers will attempt to argue that neurotoxins, including aluminium and mercury (as thiomersal) cause various neurological conditions. The amount of aluminium found in vaccines is so insignificant compared to the amounts we ingest in our foods and drink. Our body has no problem metabolises these and therefore no problem metabolising the minuscule amounts found in vaccines. Thiomersal and thus mercury has been removed from vaccines since the early 2000s due to the scare campaign associated with the word ‘mercury’, however, a Japanese study found that autism incidence continued to rise with even greater pace after thiomersal was removed.

There is no reasonably argument that explains how these chemicals may cause problems when our body is at every moment generating and metabolising these compounds apart of the natural processes that passively occur without us even thinking of it.

This graph shows the period of time where Thiomersal was used in vaccines as the MMR interval. Incidence of Autism increased significantly after thiomersal was no longer added.

Herd Immunity:

This concept is incredibly important when we consider the overall health of the population, in attempts to control epidemics, pandemics and in achieving eradication of infectious diseases. It essentially describes a form of immunity whereby large proportions (a herd) of a population are immunised against a particular pathogen. It provides a larger chance of immunity for those who have not been vaccinated and where herd immunity is established and maintained, the spread of a disease is disrupted when a large part of the population are immune or less susceptible to the disease. Herd immunity holds that with a greater percentage of the population vaccinated the probability that someone who isn’t vaccinated will encounter another person who isn’t vaccinated is significantly decreased. Under these circumstances a link in the chain of disease transmission is broken and a disease can be contained. The herd immunity threshold percentage at which a disease’s begins to be contained is generally quite high. For disease such as Diphtheria, Polio, and Rubella the vaccination percentage required is around 80 – 85% of the population. For more virulent diseases such as Measles and Pertussis the herd immunity threshold percentage is in excess of 90 – 95%.

The importance and efficacy of vaccination is well established within the vast majority of society and overwhelming advocated by the health profession. A vocal minority group of anti-vaxers who wish to believe the mistruths about the safety and importance of vaccinations places the entire population at an increased risk of disease. The science is compelling – the truths are there – the evidence is out – vaccinations have saved more lives than any other form of medicine and will continue to save lives into the future. Everyone must be vaccinated – so let’s make it compulsory!

Revolutionary Medicine – A History of the Vaccine

More than any other medical breakthrough the vaccine has saved more lives in the history of humankindImmunisation is a process whereby biological formulations provide protection against various diseases. A vaccine is created using agents which resemble pathological microorganisms and in fact are often the same disease causing organism which has been treated and weakened in some way. In the simplest terms a vaccine essentially causes our immune system to become accustomed to fighting a particular disease-causing microorganism so if that microorganism is encountered again our immune system is able to fight it before it reproduces and causes symptoms.

English physician Edward Jenner in 1798 would become famous for his breakthrough discovery of an immunization method for smallpox.

The history of immunization, however, begins as early as 1000BCE in India with evidence of inoculations being performed. Inoculation was the process by which a small amount of a live disease was given to a patient in the hope that their immune system could function effectively to build its own immunity against it. This was extremely dangerous since it carried the risk of the patient fully contracting the disease which often had fatal result.

Smallpox is estimated to have killed 300-500million people between the 16th and 20th century16th through to the 20th Century:

From the 16th century through to the early 20th century smallpox killed an estimated 300-500million people. The disease had a 30-35% fatality rate and killed an estimated 400,000 Europeans every year towards the end of the 18th century. Its proper name variola major (and variola minor for the less virulent strain) come from the Latin varius for ‘spotted’ or varus for ‘pimple’ and manifested in large raised fluid-filled bumps and extreme fever. The worst and nearly always fatal cases resulted in severe bleeding of the skin and gastrointestinal tract and toxaemia (bacterial infection of the blood).

In 1798 Jenner made a discovery which would not only lead to the eradication of smallpox worldwide but also opened a new field of immunological medicine which would form the basis of modern medicine – preventative immunization. Jenner’s work has saved more lives in humankind’s history than the work of any other person.

Born in Berkeley in 1749 amongst a family of nine children, Jenner received a strong basic education. He was inoculated at the age of eight for smallpox which had a profound effect on his lifelong general health. At the age of 14 he became an apprentice to a surgeon and was working as a surgeon with the founding father of modern medicine, John Hunter, at St. George’s Hospital by the age of 21.

Jenner successfully completes his first vaccination:

Jenner retreated to the countryside by 1773 and practiced medicine from his residence at Berkeley. The idea that cowpox (a nonfatal disease caused by touching the udders of cows) could be able to create immunity against smallpox had been raised as early as 1765 but it took Jenner’s pursuit of this idea to determine its efficacy. Jenner made the observation that since milkmaids seemed immune from smallpox that the pus from the blisters caused by cowpox must have protected them from contracting smallpox.

Flemming changed the face of modern medicine with his discovery of the preventative vaccine in 1798

By 1796 Jenner began his first trial testing his hypothesis by performing an inoculation on an eight year old boy, James Phipps. He scraped pus from the blisters of milkmaids with cowpox and injected it into both arms of Phipps causing a mild fever but no fully blown infection. At a later time he then injected Phipps with small amounts of smallpox material but no disease was contracted. Phipps was subjected to more injections of smallpox but never showed signs of the disease. Jenner’s method of immunization was adopted by governments worldwide, becoming known as vaccination from the Latin vecca for ‘cow’, and eventually led to the eradication of smallpox which was declared by the World Health Organization in 1979.

Eight year old James Phipps was Flemming's first patient whom he tested his vaccine and was thereafter immune from smallpoxMore than any other medical discovery in history, the vaccination process founded by Edward Jenner has had more effect on the health of the human race. Today, with the aid of modern technology, Jenner’s breakthrough and methodology of forming a vaccine has been applied to a vast array of disease. Many deadly diseases have been eradicated through the simple vaccination process thanks to Jenner’s insight and pursuit of an idea which others rejected as mere fiction. Because of his contribution to medicine we now live in a world where less people are killed by diseases that are preventable.