Don't catch an STI that's going around Love Island (5)
I believe the answer is:
avoid
'don't catch' is the definition.
'an sti that's going around love island' is the wordplay.
'an' becomes 'a'.
'sti' becomes 'vd' (short for venereal disease, a type of STI).
'that's going around' indicates putting letters inside.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'island' becomes 'i'.
'o'+'i'='oi'
'vd' placed around 'oi' is 'void'.
'a'+'void'='AVOID'
(Other definitions for avoid that I've seen before include "Stay away from or circumvent" , "Shy away from" , "Refrain from (something)" , "Evade - escape" , "Eschew" .)