Who Knew… Cowpox
Edward Jenner was an English physician who lived in the 18th century. During that time, smallpox was rampant and there was no good treatment or preventative measure against it. The closest anyone got to preventing the disease was through a process called variolation. This meant grinding up smallpox scabs, inhaling the powder, and you may catch a less severe version of smallpox. Afterwards, you had life long immunity. This was a dangerous practice because while the person was sick, he/she could spread the smallpox virus to others. With a mortality rate of 30%, this practice was dangerous and risky.
A Keen Observation
Jenner and other physicians observed that farm workers infected with cowpox never showed smallpox symptoms. It was as if the smallpox virus had no effect on them. This did not hold true for all the workers though; some had been infected with the cowpox virus, yet still contracted smallpox. This inconsistency led many doctors to dismiss cowpox as a way to protect against smallpox. In his publication, Jenner wrote that these observations “damped but did not extinguish my ardour.”
Jenner continued to search for an explanation for the inconsistent protection. He realized that there were two issues. First, there were many pox-like diseases that humans could contract from a cow, all called “Cowpox”. Second, in order to effectively inoculate a human, the cowpox virus must be collected at a specific time during the infection. Too early or too late during the course of the disease would mean that the cowpox had lost its “specific properties”, thus making it “incapable of producing that change upon the human frame”.
Variolation to Vaccination
After overcoming these hurdles, the rest, as they say, is history. Edward Jenner took cowpox pus from the hands of a milkmaid and successfully inoculated a boy with it. The boy never exhibited symptoms, even after repeated exposure to smallpox. Soon, hundreds followed suit. Cowpox was safer than variolation because the person would not spread smallpox after receiving the vaccine. Today, the vaccinia virus is used to vaccinate against smallpox.
In 1980, the CDC declared smallpox fully eradicated. Since bioterrorism is the only threat today, only deployed military personnel receive smallpox vaccines. For the rest of us civilians, it’s best not to forget what the world was like before vaccines. In fact, the word “vaccine” should be a reminder of its humble origins; it comes from the Latin root “vacca”, which means “cow”.