Hero potentially good to czar catching virus (6,7)
I believe the answer is:
doctor zhivago
'hero' is the definition.
(hero of the novel Doctor Zhivago)
'potentially good to czar catching virus' is the wordplay.
'potentially' indicates an anagram (letters have the potential to spell a new word).
'catching' indicates putting letters inside.
'virus' becomes 'HIV' (human immunodeficiency viruses).
'good'+'to'+'czar'='goodtoczar'
'goodtoczar' with letters rearranged gives 'doctorzago'.
'doctorzago' placed around 'hiv' is 'DOCTOR ZHIVAGO'.
(Other definitions for doctor zhivago that I've seen before include "Boris Pasternak novel" , "Pasternak classic" , "Pasternak novel - Sharif film" , "Russian title" , "Film from Pasternak's book" .)