When was the polio outbreak?
By 1910, frequent epidemics became regular events throughout the developed world primarily in cities during the summer months. At its peak in the 1940s and 1950s, polio would paralyze or kill over half a million people worldwide every year.
Before the 20th century, poor sanitation meant constant exposure to polio, which enhanced a natural immunity in the population. Small polio epidemics began to appear in Europe and the United States around 1900. Outbreaks reached pandemic proportions during the first half of the 20th century.
Join Alexa Answers
Help make Alexa smarter and share your knowledge with the worldLEARN MORE