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→Later Developments
==Later Developments==
Throughout the 19th century, in regions as diverse as England, India, and Nepal, formal vaccination programs were carried out. By 1807, over a million Indians and Sri Lankans were vaccinated for smallpox. In 1816, Sweden became the first country requiring vaccinations for children under the age of 2 for smallpox. In England, in 1853 compulsory vaccinations were passed in that year. In the United States, by the late 19th century and early 20th century, vaccination laws were developed throughout the country and by different states. For influenza, another major infectious disease, vaccines began much later. The virus for creating influenza strains was only formally notcied in the 1930s and it took Sir Frank Macfarlane Burnet and Wilson Smith in 1935 to formally understand that antiobodies can be used to fight influenza. By the late 1930s, the first tested influenza vaccines were developed. Initially, they were tested on the military. It was not until 1945 that influenza vaccines for civilians were licensed, leading to formal campaigns to vaccinate populations to seasonal influenza.
==Resistance to Vaccinations==
