Edward Jenner and Vaccination.
Infectious diseases kill more people each year than any other disease known to man. Fortunately most infectious diseases are preventable thanks largely to the efforts of Edward Jenner in the late 18th century. Edward Jenner is widely regarded as the father of vaccination due to his ground breaking smallpox vaccine. This vaccine led to the global eradication of smallpox in the 1970s, the first and only infectious disease to be completely wiped from the face of the planet. Smallpox was an immensely debilitating and often life threatening disease. As many as one in three children died of smallpox in the 18th century and even Jenner suffered from smallpox as a child. If an infected person was to survive then they were usually scarred for life as a result of the dreadful scabs caused by the virus. Smallpox infects via the lungs, enters the blood and migrates to the skin where it causes pustules full of infectious virus. These pustules eventually blister, dry out and turn into scabs that eventually fall off leaving a deep scar.
A technique known to the ancient Chinese of artificially infecting healthy people with the dried puss of smallpox victims often protected from the disease. Dried scab material was scratched onto the surface of the skin, a method referred to as variolation. This method was brought to England from Turkey in 1721 by Lady Mary Wortley Montagu. As a qualified medical doctor Jenner carried out the practice of variolation on his patients, although this often led to smallpox infection. Jenner also observed that farmers who worked in close proximity to cows were essentially protected from the effects of smallpox. This was due to them contracting the related but far less virulent cowpox. Jenner then tested the prospect of protecting people from smallpox by first infecting them with cowpox.
To do this he chose the 8 year old son of his gardener. He first took material from the pocks of a milkmaid with cowpox and administered this to the boy. Then Jenner infected the boy with smallpox by variolation. To his delight the boy did not contract smallpox and the first smallpox vaccination was a success.
The term vaccination is derived from the Latin name for cow, vacca, in honour of the technique of delivering cowpox under the skin of patients. Jenner proceeded to supply cowpox material in order to vaccinate against smallpox. Jenner showed that immunity can be generated to one pathogen through vaccination with a closely related pathogen. The World Health Organisation began its global smallpox eradication scheme in 1967 and the last case of naturally acquired smallpox was reported in Somalia in 1977. Modern vaccines still employ these basic principles as most vaccines use attenuated strains. For example, contemporary smallpox vaccines contain a strain of cowpox that has been grown in artificial cell culture so that it can no longer cause disease but still resembles the original virus enough to induce immunity to the real thing. Vaccination continues to protect millions of people world wide from many infectious diseases including polio, measles, influenza and meningitis. Not only did Jenner instigate the field of vaccination, he provided vital insights into how immunity develops to infectious organisms.