Images: left courtesy of CDC; right courtesy of Dana Johnson/Vanderbilt University Medical Center
In the mid-1950s, AIDS did not exist, chemotherapy was in its infancy, and people with genetic immune deficiencies died. At that time, smallpox was a genuine health threat and vaccinations were required, for some people once every three years. Everyone carried a World Health Organization (WHO)-approved vaccination card with their passports. Parents needed them when their children changed schools.