Health officials in American Samoa say three more people have been confirmed to have contracted measles.
Tests in Hawaii laboratories confirmed the disease in a 27-year-old woman and two boys, aged 12 years and six months respectively.
The latest results raise the territory's confirmed measles cases to 15.
Despite mass vaccinations last month, a doctor said there were still children seen at the hospital for other medical reasons who had not yet been vaccinated.
Health officials said they were continuing vaccinations throughout this week.