Type of vaccine or exam (4)
I believe the answer is:
oral
I believe this clue is a double definition.
'type of vaccine' is the first definition.
(I've seen this in another clue)
'exam' is the second definition.
(spoken academic test)
(Other definitions for oral that I've seen before include "Relating to speech" , "Like some tradition" , "Kind of exam" , "Related to the mouth" , "Vocal test" .)