All high schools, elementary school and the community college in American Samoa have reopened - but students must be fully vaccinated for measles to attend.
It follows two confirmed and 52 suspected cases of measles in the territory.
All schools had previously been told to close until 12 May.
Daycares and early childhood education centres will remain closed.
The Department of Health will continue the immunisation campaign for the daycare and early childhood age group, and a decision on when they will reopen will be made based on the vaccination coverage.
The territory's epidemiologist said there has been a decrease in calls to the Department of Health's measles hotline and a decrease in people going to the clinics with symptoms.
Scott Anesi said people may not be seeking medical care because cases could be mild and they are managing at home.
"It could be a combination of things but we're not hanging our hat to say that this thing is ramping down, we're still expecting cases and reacting as such."
Anesi also said both high schools and elementary schools are over 97 percent immunised, "so we felt comfortable with the governments decision to go ahead and open those back up".
A batch of 39 tests from people who were suspected of measles returned negative after nasopharyngeal testing, and will now be blood tested.
Two cases have been detected: one an eight-year-old girl, the other a four-year-old boy from Tafuna who goes to the same school.