Some unpopular opinions about certain type of vaccine (4)
I believe the answer is:
oral
'type of vaccine' is the definition.
(I've seen this in another clue)
'some unpopular opinions about' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'about' says the letters should be written backwards.
'laro' can be found hidden inside 'unpopular opinions'.
'laro' backwards is 'ORAL'.
'certain' acts as a link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for oral that I've seen before include "Spoken rather than written" , "Spoken test" , "Concerning the mouth" , "Type of exam" , "Relating to speech" .)