What was the Basis for the Original Smallpox Vaccine

Question

What was the basis for the original smallpox vaccine?
A) chickenpox virus
B) cowpox virus
C) rabies virus
D) smallpox virus
E) anthrax

Accepted Answer

The original smallpox vaccine was developed by Edward Jenner in the late 18th century and was based on the cowpox virus. Jenner discovered that milkmaids who had contracted cowpox, a mild and non-lethal illness, were immune to smallpox. He hypothesized that cowpox protected people from smallpox and tested his theory by inoculating a young boy with cowpox and later exposing him to smallpox, which he did not contract. This laid the foundation for the development of the first vaccine, which eventually led to the eradication of smallpox.