Vaccinations have helped decrease the number of cases of infectious diseases in the last 110 years.

The bubble chart on the left shows the number of cases of infectious diseases in the United States in the 1900s. Even though diseases like measles, pertussis, mumps, and rubella that used to infect hundreds of thousands of people have not disappeared, nowadays they infect a much lower number of people thanks to the use of vaccines, as shown on the bubble chart on the right.

Source: Vaccines.com