Vaccinations have become a very controversial topic since the initial CoViD-19 pandemic. Controversies have stemmed from a convergence of factors, notably the unprecedented speed of vaccine development and approval, which, while a scientific triumph, has led to public apprehension and skepticism about safety, efficacy, and political and financial motives undermining trust in health systems and government agencies.
This situation has been further compounded by significant political polarisation, where vaccination has become a divisive issue, entangled with political identities and ideologies. The implementation of public health measures, including vaccine mandates and passports, has sparked debates on civil liberties and personal choice, intensifying the controversy in various societies, especially in western countries.
In this article, we will discuss a successful use case of vaccination in defeating a very debilitating virus from a large proportion of Earth.
Polio
Polio, short for poliomyelitis, is a highly infectious disease caused by the poliovirus. It primarily spreads through the faecal (poo)-oral route, often via contaminated water or food. It can also spread through direct contact with an infected person.
Most infections (about 70-90%) are symptom free. When symptoms do occur, they include fever, fatigue, headache, vomiting, stiffness in the neck, and limb pain. However, in a small percentage of cases, the virus causes paralysis. Approximately 1 in 200 infections leads to irreversible paralysis, usually in the legs. Among those paralysed, 5% to 10% die when their breathing muscles become immobilised, making polio a deadly disease.
Evidence of polio dates back to ancient times, with depictions of paralysis in Egyptian art. Polio became epidemic in the late 19th and early 20th centuries in Europe and the United States.
What are the Characteristics of an Ideal Vaccine?
As per a paper published in the World Journal of Microbiology and Biotechnology called “The ideal vaccine”, the concept of an ideal vaccine involves a comprehensive set of requirements that cover safety, effectiveness, cost, administration method, stability, and longevity of immunity. These requirements aim to create a vaccine that is not only highly effective and safe for all, including immunocompromised individuals, but also accessible and practical for global use.1
Safety and Effectiveness
The ideal vaccine should be safe for everyone, including those who are immunocompromised. It should have a negligible mortality rate and minimal long-term side effects. The goal is to achieve ‘sterilising’ immunity, completely preventing infection after vaccination.
Cost-Effectiveness
Affordability is crucial, especially for inclusion in global immunisation programs like WHO’s Expanded Programme for Immunisation. A target cost of less than 50 cents per dose is mentioned, making it accessible to a broader population.
Administration Method
Non-parenteral methods of administration, such as oral vaccines, are preferred for their ease of use and reduced need for skilled personnel.
Stability and Storage
High thermal stability is essential, especially for use in tropical countries, to reduce reliance on cold chain logistics.
Multivalency and Longevity
The vaccine ideally would be multivalent, protecting against multiple diseases, and provide long-lasting immunity, potentially reducing the number of doses required.
This framework outlines a comprehensive vision for vaccine development, addressing not only the biomedical aspects but also practical and logistical considerations that are crucial for global health.
The Polio Vaccine
Pre-Vaccine Era
Before vaccines, polio was once a global scourge, causing paralysis and death. For example, in the U.S., the 1952 polio epidemic was the worst outbreak in the nation’s history, with over 57,000 cases reported.
Vaccine Development
The first effective polio vaccine was developed in 1955 by Dr. Jonas Salk (inactivated poliovirus vaccine). In 1961, an oral polio vaccine (OPV) developed by Albert Sabin came into use.
The Effectiveness of the Vaccine
The polio vaccines were and are extremely effective. There are two types: the inactivated polio vaccine (IPV) and the oral polio vaccine (OPV). IPV is 90% effective after two doses and 99% effective after three. OPV can provide lifelong immunity with just a few doses.
Cost-Effectiveness and Accessibility
The polio vaccine is also cost-effective. It’s relatively inexpensive to produce and administer, making it accessible to countries with limited healthcare resources. This accessibility has been crucial in the global fight against polio.
Herd Immunity
Polio vaccination programs have successfully created herd immunity in many regions. This means that a large part of the population is immune, which significantly reduces the spread of the virus, protecting those who cannot be vaccinated, such as people with certain medical conditions.
Post-Polio Vaccine Era
After the introduction of vaccines, polio cases plummeted. The World Health Organization (WHO) reports a more than 99% reduction in cases since the Global Polio Eradication Initiative began in 1988. An extreme example is India, where “[u]ntil early 1990s India was hyperendemic for polio, with an average of 500 to 1000 children getting paralysed daily”, but eradicated polio in 2014.2
Current Status
As of 2023, polio remains endemic in only a couple of countries. Most of the world is polio-free, thanks to effective vaccination campaigns.
Eradication Efforts
Global efforts are ongoing to achieve complete eradication of the wild poliovirus, similar to the success seen with smallpox.
Conclusion
Polio vaccination demonstrates the benefits of vaccination by effectively eradicating a once widespread and debilitating disease, being cost-effective and accessible, preventing disability, creating herd immunity, and significantly improving global health. The history of polio and its near-eradication is a testament to the effectiveness of vaccination and public health strategies.
References/Bibliography
- Ada GL. The ideal vaccine. World Journal of Microbiology & Biotechnology [Internet]. 1991 Mar 1 [cited 2023 Dec 15];7(2):105–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24424920
- John, T. Jacob, and Vipin M. Vashishtha. “Eradicating Poliomyelitis: India’s Journey from Hyperendemic to Polio-Free Status.” The Indian Journal of Medical Research, vol. 137, no. 5, 1 May 2013, pp. 881–894, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3734678/.
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