please help me find this book!!!!

I can’t remember the title or the author but i vividly remember the plot. If this rings a bell please comment the book title!!

Two best friends, girl and boy, they get diagnosed with this disease that’s been supposedly killing everyone and they get sent to this quarantine island-prison. there, they work with the other sick prisoners/patients but when people get too sick to a point where they can’t do anything they get sent to the med ward, where if you go in you don’t come out. the protagonist, a girl, discovers that the sickness is actually all made up. the people sent there were only “sick” because the wardens fed them something that made them sick resulting in a “positive” diagnosis for the “disease.” The people sent to the med ward aren’t actually sick but they get loaded onto ships and sold as slaves or workers.

Hoping someone finds this book! I read it when I was younger and I remembered it randomly but don’t remember the title or author.

by Icy-Shoulder1275