American Samoa's health department is asking parents to isolate their children if they display symptoms of chickenpox after a spike in cases in the territory.
An epidemiologist for the department, Scott Anesi, says 15 infants and young children have been in hospital with chickenpox in the last few weeks.
Dr Anesi says parents should look out for flu-like symptoms such as fever or a runny nose, and isolate their children before a rash occurs.
"A lot of times what would happen is kids are isolated after they become symptomatic with the rash and then that's when they're isolated but they were actually infectious one to two days before the rash and that's why we're starting to see the clusters."