Why will Jane and John Jones born in 2010 and 2011 respectively live four score years or longer?
Vaccination as a deliberate attempt to protect humans against disease has a short history.
In spite of this, vaccination has had a major effect on the reduction of mortality and length of life
Since the time of Edward Jenner (Figure 1), vaccination has eliminated smallpox. Smallpox was greatly feared as the leading cause of death in the western world in the 18th century. Because of the high mortality with smallpox (25%), the practice of variolation with the smallpox virus had been practiced in eastern societies and was introduced in Britain in 1721. However the subsequent infection was occasionally severe with a mortality of 1 to 2%.
In 1798, Jenner introduced vaccination with cowpox vaccine as protection against smallpox which rapidly replaced variolation. Although many were anxious regarding vaccination (Figure 2) and in spite of an anti-vaccination campaign, vaccination was rapidly accepted. During the 19th and first half of the 20thcenturies the methods of vaccination continued to be refined (Figure 3) and the quality of the vaccine improved. A worldwide vaccination campaign eliminated this disease as of 1979.