EDWARD JENNER (1749-1823)

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EDWARD JENNER (1749-1823): Edward Jenner was an English medical doctor who discovered the small pox vaccine. He was the pioneer of vaccination and also the father of immunology because of his discovery of the smallpox vaccine which was largely used to contain the smallpox disease. Edward Jenner successfully vaccinated a boy named James Phipps against smallpox (caused by variola virus) in 1798; and this provided the first direct evidence that infectious diseases are preventable. Smallpox was a disease that reached an epidemic level in the 17th-18th century, and the disease negatively impacted humanity causing high rates of morbidity and mortality as at the time.

Smallpox was at the time treated by a Chinese practice called variolationwhich involved the direct injection of smallpox fluid from an infected person into the body of a healthy person as a way of building immunity against the disease in the recipient host. However, Edward Jenner came up with the principles of vaccination/immunization, which was a modification of variolation, and involved the injection of cowpox fluid from infected cows into the body of humans. Though he could not explain the actual cause of the disease, he was honoured in the same year when he developed immunization for smallpox, a disease that is characterized by the production of small lesions called pox or pokes on the skin of the sufferer. Jenner had earlier observed that milkmaids exposed to cowpox never developed the serious smallpox and he thus hypothesized that exposure to cowpox led to protection against smallpox. This informed his decision of coming up with a strategy (vaccine) to prevent the incidence of smallpox in humans as at the time.


Variolation, which was a crude method of immunization against smallpox, was a common practice before vaccination, and this worked because the patient was exposed to a weak strain of smallpox, which did not kill, yet conferred immunity on the host against the disease. Edward Jenner discovered that cowpox could protect against smallpox, with a much lower incidence of complications than variolation. His discovery that a less pathogenic agent could confer protection against a more pathogenic one was indeed remarkable, and his works ushered in the modern era of vaccines and immunization, which is a preventive medicine. Jenner is widely known around the world for his innovative contributions in immunization and the total eradication of smallpox.

Smallpox disease caused untold mortality in the human race, but due to the discovery of a vaccine (a type of preventive medication) against it, mankind does not need to worry about smallpox any longer. His work paved way for the rapid development of vaccine and the scientific field called vaccinology, which today has helped to proffer vaccine candidates for the effective fight and prevention of a wide variety of infectious diseases. Pasteur discovered a general method for immunizing people against disease while working on chicken cholera, and he coined the term vaccination to describe this technique. Pasteur’s technique of weakening a strain by a damaging treatment or passing it through a susceptible host was termed “attenuation” and this resulted in the creation of vaccines against anthrax, rabies and other microbial diseases. Many vaccines have been developed over the years and children today receive a number of shots after birth, a practice which is greatly decreasing infant mortality around the world.

Further reading

Brooks G.F., Butel J.S and Morse S.A (2004). Medical Microbiology, 23rd edition. McGraw Hill Publishers. USA. Pp. 248-260.

Madigan M.T., Martinko J.M., Dunlap P.V and Clark D.P (2009). Brock Biology of microorganisms. 12th edition. Pearson Benjamin Cummings Publishers. USA. Pp.795-796.

Nester E.W, Anderson D.G, Roberts C.E and Nester M.T (2009). Microbiology: A Human Perspective. Sixth edition. McGraw-Hill Companies, Inc, New York, USA.

Prescott L.M., Harley J.P and Klein D.A (2005). Microbiology. 6th ed. McGraw Hill Publishers, USA. Pp. 296-299.

Singleton P and Sainsbury D (1995). Dictionary of microbiology and molecular biology, 3d ed. New York: John Wiley and Sons.

Slonczewski J.L, Foster J.W and Gillen K.M (2011). Microbiology: An Evolving Science. Second edition. W.W. Norton and Company, Inc, New York, USA.

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