A Marin County school district is taking a stand against students opting out of immunizations.

Board members for the Reed Union School District in Tiburon on Tuesday voted 4-1 to send letters supporting legislation to abolish the personal belief exemption to county health officials and state lawmakers.

School officials said 100 parents in the district have used the personal belief exemption to avoid giving their kids immunizations.

The move was prompted by the parents of a first grader with leukemia who wants to ban students who haven’t been vaccinated for measles.

Carl and Jodi Krawitt want a repeal of the state law which allows parents to opt out of vaccinations because of their personal beliefs. Their 7-year-old son, Rhett, can’t be vaccinated. His system isn’t strong enough. For five years he’s been battling leukemia and his oncologist says cancer patients can’t risk getting infected with preventable diseases.

“Not only would they be at a higher risk for a more severe form of illness from measles, for example, but it would also likely delay their therapy,” said Dr. Robert Goldsby, Rhett's oncologist.

“We’re hoping there’s some either some person or organization, maybe a politician, who sees this and says, you know what, this is something that we can do something about,” Jodi Krawitt said last month.

7 yr old Rhett Krawitt tells school board in Marin Co. kids need immunizations. Cancer survivor doesn't want measles pic.twitter.com/TJC52NBQ5i — Jean Elle (@nbcjeanelle) February 11, 2015

Since that interview, state lawmakers have introduced legislation to repeal the personal-belief exemption that allows parents to opt out of vaccinations.

Carl Krawitt says State Senator Richard Pan, a pediatrician from Sacramento, has introduced a bill to repeal the exemption.

The Krawitt family’s campaign and the publicity over the state’s measles outbreak is already having an impact on vaccination rates. Several months ago, Carl Krawitt said, the number of unvaccinated students at Reed Union schools was 6 percent. The school board on Tuesday night heard that rate has dropped down to almost 1.5 percent, Krawitt said.