As each summer rolled around during the first half of the 20th century, parents, children and health officials dreaded outbreaks of poliomyelitis, commonly called polio. This was especially true in New York City, where people lived in such close proximity to each other. The polio virus is spread by person-to-person contact, is extremely contagious and can affect the spinal cord and brain. In many cases it causes paralysis and can be fatal. Polio was often referred to as “infantile paralysis,” because it was especially prevalent in children, though people of all ages could contract the disease.