BISMARCK, N.D. (AP) -- The number of school children who aren't vaccinated against diseases has been rising in North Dakota, but the numbers are still small.

State law says children need several vaccines to enroll in school. But the children don't have to be vaccinated if parents object for moral, religious or philosophical reasons.

In the 2008-09 school year, 1.2 percent of the new students in North Dakota's public schools didn't have required vaccinations. The number was 3.1 percent in private schools.

Those numbers are going up. During the 2011-12 school year, 1.6 percent of the new public school students weren't vaccinated. In private schools it was almost 4.5 percent.

Health Department immunization coordinator Abbi Pierce says some parents are afraid vaccines can cause autism. But she says studies have thoroughly debunked that belief.