Saturday, April 25, 2015

A History of Vaccination

Active acquired immunity from disease dates back to the 15th century in China. The Chinese developed a method of inoculation called "nasal insufflation" which involved blowing a powder created from dried smallpox scabs into the nostrils. This caused a mild sickness, less severe than naturally acquired smallpox. This method would come to be known as variolation, named for the scientific name of smallpox (Variola).

Once exposed to a pathogen (a disease causing agent), the body develops an adaptive immunity which results in protection from future infection. Variolation was a well established practice through the 1700s, spreading to Western Europe and the Americas. Lady Mary Wortley Montagu was the first to promote variolation as a medical treatment, and had her children treated to protect them from smallpox.

At this time, the variolation method had advanced to a minimally invasive application of the powdered smallpox scabs on a small scratch at the skins surface. During the late 1700s, it was speculated that people who suffered from cowpox, a less severe disease, were immune to smallpox. In 1796, Edward Jenner decided to perform an experiment based on these tales. He found a milkmaid, named Sarah Nelms, who had cowpox lesions on her hands and arms. He sampled some material from one of the pox lesions, and transferred it to an 8-year old boy named James Phipps. A couple months later, Jenner again treated the boy with infectious material, though this time from a smallpox lesion. The boy did not get sick. Immune protection was established.

Edward Jenner's discovery was the dawn of the age of vaccines. In the 19th century, Louis Pasteur further developed the technological development of the modern vaccine. He created vaccines for anthrax and rabies by developing weakened viruses to be used as the vaccination agent. Like the cowpox scabs, these weakened viruses would not develop into full-blown disease, but merely stimulate the body's immune system for protection from infection.

"The Cow Pock - or - the Wonder Effects of the New Innoculation!"
image via Wikimedia Commons
The anti-vaccination movement is nothing new. Even Jenner faced scrutiny from the community; there were people who feared that the cowpox inoculations would cause them to grow cow-like appendages. While fraudulent attempts to discredit vaccinations have occurred, the science is overwhelmingly supportive that vaccines are effective, and they save lives. Today, vaccines are available for many different diseases, and yearly immunizations prevent an estimated 2 to 3 million deaths globally. Smallpox, the once prevalent and devastating disease, was officially declared eradicated in 1980. Unfortunately, there is no vaccine for fear mongering, but a knowledge and understanding of the history and pioneering work of vaccination is infectiously inspiring.




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