Edward Jenner- A review into the development of vaccines

Jenner and smallpox vaccine
Source: Wellcome Library, London (via Wikimedia Commons)
A review into the development of vaccines from the invention of the first vaccine by Jenner to the current development of the COVID-19 vaccine.

By Mili Jayadeep | Science Editor

Edward Jenner, known as the father of immunology, has revolutionized the management of deadly diseases and the occurrence of pandemics and epidemics worldwide through his work into the first vaccine

Born in 1749, he was an English physician, anatomist and biologist. Jenner was an inquisitive character who believed in using experimentation as a method of scientific study and was determined to contribute to scientific advancements. 

Edward Jenner once said:

“I shall endeavour still further to prosecute this inquiry, an inquiry I trust not merely speculative, but of sufficient moment to inspire the pleasing hope of its becoming essentially beneficial to mankind.”

At the time, smallpox was a widespread deadly viral disease that had no known cure and had resulted in a large number of deaths. Variolation was the only known method of combat against the smallpox virus which involved introducing the live virus taken from infected individuals into a healthy person’s body. This primitive form of treatment was far from an effective solution. As this method involved putting a healthy person’s life at risk as well as those around them, it did not always prevent mortality caused by the virus.

Building on the current technique, Edward Jenner reached a medical breakthrough following an encounter with a dairymaid called Sarah Nelson. She had cowpox lesions on her hand, which originated from another virus, which unlike smallpox was harmless to humans. As a result of this alternative infection to a similar virus, the dairymaid appeared to be protected from the deadly smallpox virus. 

Jenner was intrigued by this phenomenon and tested it by infecting an eight-year old child with the cowpox virus. After a brief period, the boy was inoculated with the smallpox vaccine on the second occasion. Jenner observed that the boy developed no symptoms of the smallpox disease and was determined to be immune. After further study by repeat experimentation on others, Jenner invented the smallpox vaccine. This led him publish a private book, ‘An Inquiry into the Causes and Effects of the Variolae Vaccinae’ explaining the vaccine and how it worked. 

As with all discoveries, the medical community debated Jenner’s findings before his work was widely accepted as medical practice. Owing to Edward Jenner ’s discovery and scientific methodology, vaccination schemes were rolled out throughout the 19th and 20th centuries. In 1979, smallpox was completely eradicated as established by the World Health Organisation(WHO). It is one of only two diseases to have been given this status.

Due to Jenner’s invention of vaccines, it is a widely used technique that protects human populations across the globe against various diseases. The NHS reports that vaccines are responsible for preventing approximately 3 million global deaths annually. Vaccinations have enabled the eradication or reduction of otherwise life-threatening diseases such as tetanus, polio, measles and diphtheria.

 Vaccinations work by preventing the infection of a lethal disease. When vaccines are delivered, they contain a weakened or inactive version of either a part of or all of the pathogen. This elicits an immune response where the body is stimulated to create antibodies, in the same way it would to the real pathogen, hence training the body to defend if the immunized individual were to come in contact with the actual pathogen. Once the immune system learns how to fight that particular pathogen, it retains this in memory cells and is ‘immune’ against the otherwise deadly disease. The method of vaccination therefore offers a safer and controlled manner in which diseases can be prevented. 

Vaccinations are also more effective if more people within the community or population partake in the process. This is known as herd immunity which is the level of vaccinated people needed to be able to control disease spread enough to  protect unvaccinated people. This high number makes it difficult for diseases to spread within a population hence offering greater protection to all. 

Despite this, misinformation regarding vaccines and vaccination hesitancy can reduce the effectiveness of herd immunity if people refuse to get vaccinated. The most famous example of this is the now-retracted article claiming a link between the MMR vaccine and autism. Despite being retracted and multiple studies disproving it, including an investigative piece into the alterior motives of the researcher, many members of the public have been influenced by this and are still sceptical of vaccines. This misunderstanding and mistrust is the reason why 49% of Americans say they will not get the COVID-19 vaccine when it becomes available. This figure is important and prevents us reaching the required figures for herd immunity with the community. 

Due to the rigorous testing methods that have been developed over years as well as meticulous monitoring, vaccinations are a safe and effective method of ensuring global protection against disease. It is important now more than ever to understand the science behind vaccination.

With the recent pandemic changing our lives in more ways than one could imagine, the development of a vaccine against Covid-19 has only recently become available in the UK, which shows great promise to help revert life to normal once again.

Vaccinations are still an important avenue of research, as was highlighted this year through the development of the COVID-19 vaccine. The first vaccine to be approved by the MRHA was the Pfizer vaccine, with more expected to follow in the new year. The Pfizer vaccine was administered to the first patient on November 7, with mass vaccination predicted in the remaining weeks of 2020 and beyond. 

Whilst the techniques behind the COVID-19 are very different to those used for smallpox, it is the original work of Edward Jenner that is built upon for every vaccination that allows us to prevent many fatal diseases, of which it is hoped COVID-19 could soon be one. The fundamental immunology provided by Jenner has saved millions of lives and will continue to do so with every vaccination. 

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