Reminder one with virus is in a bad way (8)
I believe the answer is:
souvenir
'reminder' is the definition.
(I know that souvenir is a type of reminder)
'one with virus is in a bad way' is the wordplay.
'with' is a charade indicator (letters next to each other).
'is in a bad way' indicates anagramming the letters.
'one'+'virus'='onevirus'
'onevirus' with letters rearranged gives 'SOUVENIR'.
(Other definitions for souvenir that I've seen before include "something worth keeping" , "Keepsake, memento" , "Reminder of holiday" , "remember seeing this?" , "Reminder of past events" .)