A vaccine makes you immune against a disease.
Do you know what the word vaccine actually means?
What has the word vaccine have to do with cows?
Edward Jenner invented the vaccine in 1796. The deadly disease back then was called Smallpox.
Jenner heard a milkmaid say, “I shall never get smallpox because I’ve had cowpox”.
Smallpox and Cowpox are from the same family.
If you were infected with the less deadly cowpox, it seemed to Jenner that smallpox wouldn’t affect you.
To see if his ideas were correct he found a dairymaid Sarah Helms, who had cowpox which she got from a cow called Blossom. He then inoculated James Phipps with cowpox, the 8 year son of his gardener. He then inoculated the boy with smallpox and it didn’t affect him.
