Since the beginnings of recorded history, humans have shown great interest in the state of their health and have recognised the vulnerability of the immune system to the attack from disease-causing agents. Although due to the contribution of MacFarlane Burnet’s work in the middle of the 20th century and advancements in medical technology; vaccination programs have become an effective ‘lifeline’ in preventing the spread and occurrence of common diseases such as polio.

Polio also known as poliomyelitis is a common, acute viral disease that invades the central nervous system. The disease is sub-divided into three types as either; Sub-Clinical (no symptoms), Non-Paralytic (mild symptoms) or Paralytic (produces full/partial paralysis).

Polio is caused by the pathogen poliovirus, a highly contagious virus specific to humans. There are three known types of polioviruses (1, 2 and 3) each causing a different strain of the disease. All are members of the viral genus Enterovirus; a group of RNA viruses that colonise the gastrointestinal tract (specifically the intestines).

Polio is a highly infectious disease transmitted by direct contact to an infected individual, via primarily the faecal-oral route, which occurs with poor sanitary conditions. The virus enters the body through the mouth and multiplies in the lymphoid tissues in the throat and gastrointestinal tract. Once absorbed, it moves to the central nervous system through the bloodstream where it destroys the motor neuron cells. Factors that increase the risk of polio infection or affect the severity of the disease include malnutrition, physical activity and pregnancy. The incubation period of polio, from the time of first exposure to first symptoms, ranges from three to 35 days.

Although polio can cause paralysis and death, the vast majority of people who are infected with the poliovirus don't become sick and are never aware they've been infected with polio. When symptoms do appear, there are differences depending on the type of polio. Sub-Clinical polio often only lasts 72 hours or less with general symptoms of headaches, nausea and sore throats. Non-Paralytic polio last days to weeks with flu-like symptoms of diarrhoea, irritable muscle spasms and back stiffness. Paralytic polio presents long-term severe symptoms of limb deformation.

Before the introduction of the polio vaccine, little could be done to prevent individuals becoming infected by polio. Children under five years of age became easily susceptible and primary hosts of the disease, due to their undeveloped immune systems. In terms of occurrence, this lead to extremely high incidence rates globally.

Polio had a multifaceted impact on individuals and the society. For individuals, polio had a physical impact. With the cause of having no options regarding treatment in correcting the deformity, such as surgery or physical therapy; individuals as suffers of the virus had to spend the rest of their lives coping with severe disability or deformity as well as any pain experienced from the infection. In effect this restricted their way of living and often lead to mental health issues such as depression.
For the society, polio had psychological impact. As a community, people developed a strong fear that they or their family members or friends would catch polio. In effect this limited the society’s interaction in supporting one another through such a difficult time. As a result of this fear of infection; the society’s fertility rate fell below its death rate, which lead to an ageing of the population.

A vaccine is an antigenic substance prepared from the causative agent of a disease or a synthetic substitute, used to provide immunity against one or several diseases.
Vaccination works to stimulate a specific immune response that will create B and T cell responses specific to a certain pathogen. After vaccination or natural infection, long-lasting memory cells persist in the body and can lead to a quick and effective response should the body encounter the pathogen again.

In 1998, the World Health Organisation (WHA) launched a Global Polio Eradication Initiative. A feature of this program was that it targeted the widespread vaccination of children less than 5 years. A major reason for the programs success was that it only targeted countries where the disease was still endemic. This enabled them to eradicate a higher number of incidences of the disease in the shortest amount of time possible. This success is supported by 450 million children under 5 years in were Immunised during National Immunisations Days.

Since 1988 the cases of polio disease have decreased by over 99% in more than 125 endemic countries. There are only four countries in the world that remain polio-endemic. The remaining countries are Afghanistan, Nigeria, Pakistan and India. About 98% of all global cases are found in the last three countries.

The Global Polio Eradication Initiative has proven effective in reducing all cases of polio around the world. The entire western Pacific region, including Australia has been declared polio-free since 2000. This effectiveness of completely eliminating the incidence has resulted from their continued persistence in offering free polio vaccinations to children up to 9 years of age and Aboriginal and Torres Strait Islander people, refugees and asylum seekers from ten years of age.