One of the most successful therapeutic strategies to prevent or control various diseases is by “vaccination” protocol The terms “vaccine” and “vaccinology” came into use soon after Edward Jenner discovered the smallpox vaccine. Jenner called the smallpox vaccine “variola vaccinae.” For his contribution, Jenner is often referred to as the “Father of Vaccinology” (though this epithet is sometimes also used for Louis Pasteur). The word “vaccine” originated from vacca, a Latin term for the cow. The credit for the first use of the term “vaccine” goes to Swiss physician Louis Odier (1748-1817), and the terms “vaccination” and “to vaccinate” were first used by Richard Dunning (1710- 1797) A vaccine is a biological preparation that can be used to safely induce an immune response that confers protection against infection and/or disease on subsequent exposure to a pathogen.