Acting against or preventing virosis (disease caused by a virus).
From 'anti-' combined with 'virotic' (from 'virus' plus the medical suffix '-otic'). This is a specialized medical term parallel to 'antiviral.'
This word is so rare that it's barely used anymore—medical professionals switched to 'antiviral' because it's shorter and clearer, showing how language naturally selects the most efficient terms.
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