Hi all.
Spoilers for the candlekeep adventure so beware.
Here is the description of the curse
Those who hear the melody of the rhyme find it to be irresistibly catchy, and they hum it over and over again. Such individuals have become cursed.
The rhyme acts as a summoning ritual intended to restore Shemshime. When enough people join in the singing of the rhyme, or enough time passes while people are singing it, the ritual will be completed. As that occasion approaches, Shemshime’s power grows. Anyone who hears the cursed tune is in turn cursed to hum or sing it. They are then capable of transmitting it further.
Resisting the Rhyme
The characters can will themselves not to sing the rhyme