In 1796
The story of vaccines did not begin with the first vaccine–Edward Jenner’s use of material from cowpox pustules to provide protection against smallpox. Rather, it begins with the long history of infectious disease in humans, and in particular, with early uses of smallpox material to provide immunity to that disease.  The history of smallpox holds a unique place in medicine. One of the deadliest diseases known to humans, it is also the only human disease to have been eradicated by vaccination. Symptoms of a typical smallpox infection began with a fever and lethargy about two weeks after exposure to the Variola virus. Headache, sore throat, and vomiting were common as well. In a few days, a raised rash appeared on the face and body, and sores formed inside the mouth, throat, and nose. The first known cases of smallpox go back to 1350 BC and the disease has been known for a very long time. Dr. Campbell identified how smallpox is spread. Edward Jenner is cred … ited with developing the smallpox vaccine in 1796. Dr Edward Jenner discovered the vaccine in 1796 and published his findings in 1798. Edward Jenner invented the vaccine for small pox in 1798. He  prepared the vaccine f … rom the cow pox virus. His discovery could  save more lives than any other medical discovery Publication of the Inquiry and the subsequent energetic promulgation by Jenner of the idea of vaccination with a virus other than variola virus constituted a watershed in the control of smallpox for which he, more than anyone else deserves the credit. In the United States, the smallpox vaccine is the only FDA-approved treatment for smallpox and monkeypox. As with smallpox, vaccination after infection is effective if the vaccine is given before symptoms develop. Abstract. Human beings have benefited from vaccines for more than two centuries. Yet the pathway to effective vaccines has been neither neat nor direct. This paper explores the history of vaccines and immunization, beginning with Edward Jenner’s creation of the world’s first vaccine for smallpox in the 1790s. We begin our history of vaccines and immunization with the story of Edward Jenner, a country doctor living in Berkeley (Gloucestershire), England, who in 1796 performed the world’s first vaccination. 4 Taking pus from a cowpox lesion on a milkmaid’s hand, Jenner inoculated an eight-year-old boy, James Phipps. Edward Jenner, an English physician, discovered the smallpox vaccine in 1796. He came upon this discovery by noticing that milkmaids who had the cowpox virus, a less threateni … ng disease, did not catch the dangerous smallpox. Jenner then infected an 8-year-old boy with the cowpox. Making the world better, one answer at a time. Dr Edward Jenner discovered the vaccine in 1796 and published his findings in 1798. Edward Jenner invented the vaccine for small pox in 1798. Initially, the terms vaccine / vaccination referred only to smallpox, but in 1881 Louis Pasteur proposed that to honour Jenner the terms be widened to cover the new protective inoculations being introduced. In the United States, the smallpox vaccine is the only FDA-approved treatment for smallpox and monkeypox. As with smallpox, vaccination after infection is effective if the vaccine is given before symptoms develop. Smallpox vaccine, the first successful vaccine to be developed, was introduced by Edward Jenner in 1798. He followed up his observation that milkmaids who had previously caught cowpox did not later catch smallpox by showing that inoculated cowpox protected against inoculated smallpox. In the United States, the smallpox vaccine is the only FDA-approved treatment for smallpox and monkeypox. As with smallpox, vaccination after infection is effective if the vaccine is given before symptoms develop. Although the first vaccine against smallpox was developed in 1796, greater than 100 years later its use had not been widespread enough to fully control the disease (4). Four other vaccines -- against rabies, typhoid, cholera, and plague -- had been developed late in the 19th century but were not used widely by 1900. 
http://www.historyofvaccines.org/content/timelines/all http://www.historyofvaccines.org/content/timelines/smallpox http://www.answers.com/Q/Who_discovered_the_smallpox_vaccine_and_when https://en.wikipedia.org/wiki/Smallpox_vaccine http://content.healthaffairs.org/content/24/3/611.full http://www.answers.com/Q/When_was_the_smallpox_vaccine_invented https://en.wikipedia.org/wiki/Smallpox_vaccine https://en.wikipedia.org/wiki/Smallpox_vaccine http://www.cdc.gov/mmwr/preview/mmwrhtml/00056803.htm
when was the smallpox vaccine discovered