As the article points out:
This chart is why vaccines matter. It compares declines from the number of cases of communicable diseases during an average year in the 20th century, to cases reported in 2010. And for diseases that we’ve fully vaccinated against — things like smallpox, which used to infect nearly 30,000 people each year — the decline is 100 percent.
Add all these up, subtract the cases that still exist, and you come out to just shy of 1 million cases of disease prevented annually.
Bottom line, the more vaccinated the populace the less likely diseases or illnesses can make a comeback. If people don’t diseases like chicken, small pox or even pertussis can return. Since it is flu season, please consider getting a flu shot.
UPDATE: Another news source I found proves vaccines work with three charts.