What is vaccinate? How to use in English

The origin of the word "vaccinate" can be traced back to the late 18th century, when the practice of vaccination was introduced by an English country doctor named Edward Jenner. Jenner's work was inspired by a common belief during that time that individuals who contracted cowpox, a benign disease caused by a virus found in the milk of cows, were immune to smallpox, a deadly and highly contagious disease caused by the variola virus. Jenner's discovery came about in 1796, when a young dairymaid named Sarah Nelson came to Jennings complaining of cowpox-like lesions on her hands. Jennings, seeing an opportunity, suspected that inoculation with cowpox matter could protect against smallpox. He took pus from Nelson's lesions and scratched it into the skin of an eight-year-old boy named James Phipps, even though Phipps had already been inoculated with smallpox. The experiment worked, and the boy did not contract smallpox. This was the world's first vaccination, and Jenner coined the term "vaccination" from the Latin word "vacca," which means cow, in honor of the cow from which the virus was derived. The practice of vaccination quickly gained popularity and has since saved millions of lives around the world.