In the latter part of the 20th century, an unusual and enduring mark started to become more widespread among the general population. It was a little, round scar on the upper arm, a permanent reminder of a period when people all across the world lived in fear of a virus that was both lethal and incredibly contagious — smallpox.

Before the 1970s, getting vaccinated against smallpox was a required part of growing up for a great number of people. The vaccination utilized live Vaccinia virus to elicit an immunological response in the body, so preparing it to protect itself against the deadly Variola virus, which was the causative agent of the debilitating smallpox disease.

Although the operation itself was uncomplicated, the effects it had were everything but understated. Following the administration of the vaccine, a chain of subsequent events took place. At the site of the injection, blisters developed, causing the patient some little discomfort. After a short period of time, these blisters went through the process of healing, which resulted in the formation of a crust.

Nevertheless, the circular scar served as a visible reminder that this one-of-a-kind adventure had reached its conclusion. When the needle was used to make a puncture in the skin, a very small amount of the vaccine was given, which resulted in the formation of blisters. In the beginning, the region surrounding the injection site swelled, which resulted in some momentary discomfort that lasted for approximately six to eight hours.

After some time had passed, the edema went away, and the location of the injection restored to its previous appearance. However, after about six to eight weeks, a little bump that looked like a mosquito bite would appear. It was the beginning of a wonderful change that was also a little scary. Those who were not familiar with the process were surprised to see the lump develop into a tumor as it grew larger over time. This caused them to raise their eyebrows.

This tumor eventually split open and started leaking a clear fluid as it worked its way toward complete rupture. An ulcer had taken the place of the bump, which would have been a cause for concern for some individuals. However, this was all predetermined and part of the plan. It took anywhere from two to five weeks for the wound to heal completely, during which time the ulceration and healing process occurred anywhere from two to three times.

The ultimate effect was a scar that remained permanently, and it was this scar that served as evidence that a person had successfully been vaccinated against smallpox. The terrible disease known as smallpox was responsible for a large number of deaths throughout human history. Since ancient times, people had been terrified of this disease because of its capacity to wipe out entire communities.

However, by the early 1970s, smallpox had been completely eradicated throughout the Western world. One of the primary contributors to this success was the widespread use of smallpox vaccinations. Because there was less of a chance that people would be exposed to this once-terrifying virus, vaccination against it was no longer necessary.

The practice of administering immunizations against smallpox progressively faded into antiquity as the years went by. In the 1980s, it became abundantly clear that the Variola virus, which was responsible for the spread of smallpox, did not pose a substantial threat any longer. People wouldn’t be required to go through this one-of-a-kind vaccine experience in order to live their lives.

If you see a little, round scar on someone’s upper arm, keep in mind that it’s more than just a scar; it’s a reminder of a time when people all over the world banded together to combat a horrible disease and ultimately prevailed over smallpox. The smallpox epidemic may have left an indelible scar, but it also left a legacy of human resiliency and resolve that will endure forever.