Joe Hutch
Mate of the bloke
Watch out ... irony ahead.
Once you have immunity to a disease you have immunity for life, which is why booster shots aren't needed and why someone who's had chickenpox as a kid can't get shingles as an adult.
[insert emoticons here: ]
No, wait...
The irony has happened.
Joe
You talk about irony, but you need to be more specific. Is that irony you speak of 'normal' irony, or 'Alanis' irony?
The OED defines irony as: 'The expression of one's meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect'
Here is an OED cite for the former:
1914 S. Lewis Our Mr. Wrenn iv. 57 ‘Nice work,’ Satan interjected from time to time, with smooth irony. ‘Sure. Go ahead. Like to hear your plans.’
The latter is more or less summed up by the phrase 'bloody typical!'