Figure 1. Major milestones in the historical path of the development of vaccinology and vaccine design.

A method for preventing naturally acquired smallpox called ‘variolation’ was discovered in India before 1,000 A.D. and was in use also in China and Western Asia. This method, which consisted of the inoculation of pustule material from smallpox-infected patients to healthy individuals, was introduced in Europe in 1,721 by Lady Mary Wortley Montagu. The first real vaccination practice was introduced when Edward Jenner used pustule material from humans infected by cowpox to protect against smallpox.