How many letters does the top answer for “the act of making immune (especially by inoculation)” have?

The most common answer is immunisation (12 letters).

Crossword clue: the act of making immune (especially by inoculation)

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

immunisation 12 letters wn-def

the act of making immune (especially by inoculation)

immunization 12 letters wn-def

the act of making immune (especially by inoculation)