Drug requiring vaccination, alternatively with iodine (9)

I believe the answer is:

jaborandi

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'drug' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I can't see?

'vaccination alternatively with iodine' is the wordplay.
'vaccination' becomes 'jab' (I can't explain this - if you can you should believe this answer much more).
'alternatively' becomes 'or'.
'with' becomes 'and'.
'iodine' becomes 'I' (I is the chemical symbol for iodine).
'jab'+'or'+'and'+'i'='JABORANDI'

'requiring' is the link.

Can you help me to learn more?

I've seen this clue in The Times.

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