Biology Research Assessment: Importance of Vaccines against Polio

Claim

Vaccines are not required for the overall health of society.

Rationale

Groups such as The Australian Vaccine Network (AVN) have raised concerns over the administration of vaccines in Australia due to their perceived negative public health consequences. This led to the claim:

“Vaccines are not required for the overall health of society.”

The claim contains the following aspects; vaccines and their health consequences; the requirements and definition of overall health in society; and where the line is drawn in public health. With consideration and preliminary research into these aspects, the following broad research question was developed: Has a dangerous disease been eradicated by vaccines?

The Australian government has administered vaccines since 1932 for many pathogens that are mostly life-threatening such as Poliomyelitis (Polio), Meningococcal and Influenza (NSW Health Department, 1997). Despite the eradication of numerous diseases directly through the immunisation program, the AVN (2019) website specifically cites the Polio vaccine as ineffective and dangerous, claiming that it “has not achieved the goal…of the vaccination program”. However, Polio was a deadly disease that affected millions with crippling health consequences until that vaccine led to complete eradication of the disease in Australia (South Australia Health, 2014).

Thus, with available sources and data surrounding Poliomyelitis and the vaccination program that directly evidence against the claim, it was chosen as the focus of the investigation. Australia will be used as a case study as the AVN specifically protests Australian administration of vaccines in addition to statistics concerning Australia’s Polio epidemic being accessible. As a result of the sufficient evidence available to evidence against the claim, the following research question was developed:

Research Question

“Has the production and administration of the Polio vaccine/s affected the quality of life of children in Australia?”

Background

Vaccines were pioneered by the observation that linked exposure to a disease or a less potent version would grant ‘immunity’ to the individual (The History of Vaccines, 2019). Spurred by this observation, vaccines would be developed for the worst and most widespread diseases such as Measles, Smallpox and Polio among others.

Vaccines bolster or fortify the immune system against a specific disease using the adaptive immune response. The adaptative immune response relies on T-cells and B-cells to fight against antigens (foreign body/pathogen) through the cell-mediated response and antibody responses depicted in figure 1.

Figure 1: Adaptive immune system

Vaccines don’t contribute to the cell-mediated responses that use killer T-cells to eliminate infected cells, rather utilising the antibody response (Alberts B, 2002). The Antibody response builds immunity to a pathogen. Polio vaccines introduce the 3 wild strains of Poliovirus in either an inactivated form or a live, weakened virus version. Immature dendric cells (IDCs) recept the presence of the pathogen as well as its characteristics. B-cells, now activated by the IDCs, use those identified characteristics to develop antibodies specific to the pathogen (Janeway CA Jr, 2001). The antibodies will amass to the antigen and bind using matching characteristics to inhibit it (figure 2). The slowed and incapacitated cells are thus marked for destruction through the non-specific immune response of phagocytes that ingest the antigen (Alberts B, 2002).

Figure 2: The function of antibodies: to bind and inhibit

The World Health Organisation (2019) defines quality of life as “a state of complete physical, mental, and social well-being”. A disease that inhibits a person’s physical health lowers quality of life, especially if the effects are permanent.

Poliomyelitis is a highly contagious virus that spreads quickly among children due to a long incubation period (the time between infection and first symptoms) and the method of transmission through “water…contaminated by faeces” (Sophie Ochmann, 2019). Once infected, Poliomyelitis multiplies in the mouth and pharynx (infection point) until it reaches the gastrointestinal tract. Polio is an incurable disease assisted by two effective virulence characteristics; Immunoglobulin-like bonding proteins that help in disguising the pathogen; and the ability to perform cytolysis which allows for faster infection within the body (Volney, 2001). ‘Herd immunity’ is the term used to describe a population that is immunised at a rate around or above 90%. The effect is a population that stops outbreaks of a pathogen.

Evidence and Analysis

Poliomyelitis lowers the quality of life for those that experience the effect of paralytic Polio. Polio infections lead to 72% of cases are asymptomatic but still able to communicate the disease as hosts, 24% experiencing a minor sore throat and fever and 1-5% will experience sensations and stiffness around the body. However, less than 1% will develop into paralytic Polio (CDC, 2018). This will often result in complete recovery, however, 1 in 200 infections will have a form of permanent paralysis (figure 3).

Figure 3: The risk of paralytic Polio (CDC, 2018)

Paralysis occurs when the virus enters the bloodstream from the mouth and throat and destroys the motor neurons of the brain stem (CDC, 2019). The symptom of Paralysis is most common in the spinal cord (79%), with the pronounced effect of “the asymmetrical paralysis of the lower limbs” (Flaherty, 2012). The result is the loss of motor control and mobility, restricting one’s quality of life (figure 4).

Figure 4: Spinal Polio paralysis

Bulbar Polio is a very serious type that attacks and permanently damages the motor neurons of the brain stem that leads to breathing and talking difficulty (MalaCards, 2019). However, Bulbospinal polio (2%) is a combination of the two that has a greater mortality rate range of 25-75% above the average of 30% consistent with paralysis (AIHW, 2018). Mortality is a result of breathing-related complications. Tank respirators (Iron Lungs), were developed to assist the breathing of Polio paralysis patients. While it did save many lives, it required the patient to spend upwards of 16 hours daily within a constrictive chamber that severely limited movement and speaking ability (figure 5). Many hundreds were distributed to Australia for children, then adults for a life of reliance. Polio-associated breathing difficulty either causes death or that permanent reliance on an archaic machine.

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Figure 5: The Iron Lung

Poliomyelitis was not a prevalent disease in the 19th century, but it became an endemic disease in the 20th as a result of changing sanitary conditions and childhood exposure for natural immunity to develop (Figure 6).

Figure 6: Recorded deaths by Poliomyelitis during the 19th century (Smallman-Raynor, 2006)

Year Location Cases (Deaths)

1808 Göteborg, Sweden 4

1835 Worksop, UK 4

1841 Louisiana, USA 10

1841 Modums, Norway 14

From dozens of deaths over a century to many thousands, Australia had a peak of 357 deaths in a single year due to Polio. In fact, Polio-related deaths occurred for decades after the outbreaks in the middle-century, evident in figure 7. Even contracting and surviving Polio leads to a lowered life expectancy, either through the disabled limbs or Post-Polio syndrome that resurfaces the Poliovirus. Post-Polio syndrome affects 25-40% of Polio survivors and carries the risk of death or lowered life expectancy, that is the cause of Polio-related deaths still ongoing (14 in 2015) in figure 7 (NINDS, 2019).

Figure 7 (AIHW, 2018)

On the other hand, a global trend of decreasing deaths and notifications of Polio was occurring in the 1950s, figure 8 depicts Australian notifications.

Figure 8: (AIHW, 2018)

Figure 7 and 8 both illustrate a drop of deaths and notifications, the Inactivated Polio Vaccine (IPV) was introduced and administered to Australians in 1956. This led to the exponential drop in cases from 1,194 in 1956 to just 100 in 3 years. 16 years later in 1972, complete eradication of the disease occurs in Australia from decades of pandemic that saw a peak of 2,698 infected in 1938. However, there was a single spike in deaths and notifications after the introduction of vaccines between 1961-1962 as a consequence of not enough children being vaccinated. Herd immunity had not been achieved with Victoria only having 72% of children immunised (National Museum Australia, 2018). With an outbreak directly attributable to the unimmunised, the response was swift and widespread vaccinations leading to the eradication just years later.

The IPV would only result in rare, insignificant side-effects while protecting the Central Nervous System (CNS) of the individual (preventing paralytic Polio). However, an Oral Polio Vaccine (OPV) was soon developed that uses a live version of the virus with the advantage of protecting the gastrointestinal tract as well as the CNS. The OPV thus has a benefit to those unvaccinated and curbs further spread by the individual (Sophie Ochmann, 2019). OPV is only used to control outbreaks quickly in developing countries (Global Polio Eradication Initiative, 2018).

The almost complete eradication of Polio in the world significantly reduced the Polio-attributable deaths by an estimated 600,000 people a year (National Museum Australia, 2018). Consequently, reducing the deaths and afflictions caused by Polio greatly increased the quality of life for those that can go without those ill effects in the next generation.

In spite of this, the AVN still raises concerns over the efficacy and safety of the Polio vaccine-specifically due to Vaccine-Induced Polio (VIP). VIP can occur through rare phenomena and the improper administration of the OPV. Vaccine-Associated Paralytic Polio (VAPP) is a rare phenomenon that occurs in but 1 of 2.7 million doses without the characteristic of infectivity (WHO, 2015). Circulating Vaccine-Derived Poliovirus is a more infrequent anomaly that arises when communities have not been sufficiently immunised against the virus, however, only 760 cases have occurred after 10 billion doses (WHO, 2017). Despite the risk of OPV, an estimated 16 million cases of paralytic Polio have been averted since 1988 (Sophie Ochmann, 2019). Moreover, OPV is only used is outbreaks and is not available in the US or Australia, the safe IPV is used. Australian Anti-Vaccination groups have no standing to claim that the Polio vaccine has 'not achieved the goal…of the vaccination program” as the widespread positives of Australia being Polio free overshadow the rare effects of OPV.

Evaluation of Sources

The evidence provided does contain some issues that arise with the use of historical data in the field of medicine. The most affected data is the standard of recording the true number Polio cases as Ochmann (2019) describes, “with 72% of polio infections not leading to any symptoms – and 99.5% of cases resulting in only temporary symptoms…it is difficult to record all cases of Polio.' To combat this, speculative/estimative data has been avoided for analysis in favour of the more precise metric of ‘Polio notifications’, which is not necessarily how many Polio cases but is more accurate in tracking outbreaks and eradication than a speculative data set. The choice for Australia as the focus of the investigation narrowed the available data sets as Australia uses the Department of Health to collate the data on deaths and notifications. Thus, the data is only available from them leading to gaps within the data as seen in figure 8 for 1942 and 1950 cannot be filled except by further investigation into speculative data analysis that would come at the cost of accuracy. Background information of Polio and vaccines is well-documented and comes from reputable government agencies such as the CDC and State health departments.

However, further investigation would have to involve the broadening of the research to contain not only the Polio epidemic and control that led to the increased quality of life, but other vaccines and pathogens. Vaccines that have had negative health effect, as well as those that have eradicated other diseases (smallpox), would assist in categorically refuting the claim.

Conclusion

With consideration of the evidence obtained, the claim “vaccines are not required for the overall health of society”, is tentatively refuted concerning the pathogen Polio. The specific research question assisted a focused investigation and analysis to prove that vaccines have reduced Polio, thus increased the quality of life for children that don't have to experience the effects of paralysis and decreased life expectancy. However, vaccines immunise against many diseases and Polio is but one example. An examination of many pathogens and their vaccines would broaden the research greatly but could lead to a categorically refuted claim about vaccines not being a benefit to the overall health of society.