The history of immunizations begins in 1796, when the English physician Edward Jenner discovered that the individuals who had been exposed to cowpox virus developed an immune response that protected them against human smallpox, and, subsequent contact with this virus did not cause them to contract the disease.The concept of “vaccine” arose as a result of this discovery; the term vaccine derives from the Latin vaccae and refers to any microorganism or material which, when administered to an individual, causes an immune response that provides protection against natural disease.The use of vaccines in immunization programs has enabled preventing serious contagious and infectious diseases and avoiding epidemics.
