Re: What was the first virus was first to have tested for a vaccine?

Just over 200 years ago an English physician, Edward Jenner, noticed that milkmaids rarely caught smallpox. He reasoned that this was because they had previously caught a similar but relatively harmless disease, cowpox. Few people infected with cowpox subsequently caught smallpox. Jenner tested his reasoning by infecting a young boy with cowpox then exposing him to smallpox. The boy did not develop smallpox, so Jenner repeated the process with others – this was the first use of vaccination. (The word ‘vaccination’ comes from Jenner's use of cowpox; the Latin word vacca means cow.)

http://www.the-scientist.com/yr1996/apr/research_960401.html

http://www.sc.edu/library/spcoll/nathist/jenner2.html

http://library.thinkquest.org/23054/basics/page2.html

http://www.science.org.au/nova/012/012box02.htm

Moderator's Note
Before Jenner, both ancient Chinese and Indian physicians were known to take the scabs from patients suffering from mild smallpox, grind them with other materials to a fine powder and blow it into the noses of susceptible individuals as a form of vaccination against the disease.