How Vaccines Have Beaten Diseases

Some diseases have been eradicated with no new cases of polio or smallpox in decades in the United States compared to a 20th century average of more than 10,000 cases per year, according to the Centers for Disease Control and Prevention.

Progress in eradicating measles has stalled in recent years but is nowhere near the annual case load seen in the 20th century, when half a million people were infected in an average year.

Its prevalence has fallen by more than 99 percent due to vaccinations, along with a whole host of other diseases such as pertussis (whooping cough), mumps and rubella.