Edward Jenner was the first to test a method to protect against smallpox in a scientific manner. He did his study in 1796, and although he did not invent this method, he is often considered the father of vaccines because of his scientific approach that proved the method worked.The method Jenner tested involved taking material from a blister of someone infected with cowpox and inoculating it into another person’s skin; this was called arm-to-arm inoculation. However, by the late 1940s, scientific knowledge had developed enough, so that large-scale vaccine production was possible and disease control efforts could begin in earnest.The next routinely recommended vaccines were developed early in the 20th century. These included vaccines that protect against pertussis (1914), diphtheria (1926), and tetanus (1938). These three vaccines were combined in 1948 and given as the DTP vaccine.