ANATOMY

Detailed explanation-1: -Vaccination became widely accepted and gradually replaced the practice of variolation. At some point in the 1800s, the virus used to make the smallpox vaccine changed from cowpox to vaccinia virus .

Detailed explanation-2: -The vaccine is made from a virus called vaccinia, which is a poxvirus similar to smallpox, but less harmful. The smallpox vaccine contains live vaccinia virus, not a killed or weakened virus like many other vaccines.

Detailed explanation-3: -Dr Edward Jenner created the world’s first successful vaccine. He found out that people infected with cowpox were immune to smallpox. In May 1796, English physician Edward Jenner expands on this discovery and inoculates 8-year-old James Phipps with matter collected from a cowpox sore on the hand of a milkmaid.

Detailed explanation-4: -Cowpox is a skin disease caused by a virus belonging to the Orthopoxvirus genus. Sporadic human cases of cowpox have been reported in Europe, mostly linked to handling of infected animal, usually rodents and cats. Human infection results from direct contact with an infected animal.