"The Doc said he would inoculate me with a vaccine, then I'd be immunized"

With Swine 'Flu (don't forget that apostrophe, folks!) and regular 'flu stalking the land, conversation this Fall has often turned to the subject of the 'flu shot. Or indeed shots, plural, because regular influenza requires a different (... uh... vaccine? inoculation?) shot from the more scary H1N1 virus, also known as Swine 'Flu.

What is the difference, I wonder, between these verbs, which we all use interchangeably? To vaccinate; to immunize; to inoculate?

Inoculation, strictly speaking, means putting something into another organism where it will grow or reproduce. It is used most commonly to refer to putting serum, vaccine, or antigenic substance into the body of a human or animal, especially to produce or boost immunity to a specific disease.

Vaccination: the word originates with the work of Edward Jenner, sometimes known as the Father of Immunology, because he figured out that milkmaids did not seem to catch Smallpox (and had fair, unmarked skin), because their work with cows (French: la vache, from Latin: vacca), caused them to catch a milder variety of the disease, Cowpox, which produced an immune response. Ergo: they could not catch Smallpox.

Immunization means the process by which an individual's immune system becomes fortified against a disease or pathogen.

After all that, I sort of see how each word differs in its definition, but also how they overlap. It's time for a joke: last winter, a man says to his friend, "I said that Americans would never elect a black man as President, never in a million years, pigs will fly before that ever happens! And the next thing that happens? Swine 'Flu!"

[Adding a final word or three to this post: a fairly common expression at home in Ireland, aimed at anyone who talks a lot, is: "Where you inoculated with a gramophone needle when you where a child?" It seems to be a common expression across the English-speaking world].