Drugs taken here work on virus every now and then, supported by doctor and nurse (5,3)
I believe the answer is:
opium den
'drugs taken here' is the definition.
(where opium might be taken)
'by doctor and nurse' is the wordplay.
'by' becomes 'opium' (I can't explain this - if you can you should give a lot more credence to this answer).
'doctor' becomes 'd' (eg in PhD, Doctor of Philosophy).
'and' means one lot of letters go next to another.
'nurse' becomes 'en' (abbreviation for enrolled nurse).
'opium'+'d'+'en'='OPIUM-DEN'
'work on virus every now and then supported' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
(Other definitions for opium den that I've seen before include "smoke-filled room" , "Place to buy and smoke dope" , "Place to take drugs" , "place for addicts" .)