What is the importance of vaccines for world health?

In 1999, vaccination was listed by the CDC as one of the 10 greatest achievements of the 20^th century. Vaccinations have changed the face of infectious diseases by lowering the incidence dramatically of many infectious diseases that were quite common less than 50 years ago, and have resulted in increasing health and life expectancy of the population.

Diseases that were rampant in areas where antibiotics were unavailable or where the medical system was not advanced enough to treat these infections have been controlled by vaccinations. Some of these diseases have virtually disappeared from the face of the earth as a result of ongoing vaccination programs. Examples include smallpox, which has been eradicated, and poliomyelitis, which is getting close to elimination. Unfortunately, in some countries were vaccine programs have been cut back, the incidence of polio has started to increase again.