OAKLAND (KPIX 5) — Scores of California students may be sent home on their first day of school because of a new vaccine law that took effect this year.

The new state law took effect July 1. Now, parents can no longer use personal or religious beliefs as a reason not to have their kids immunized.

This school year, kindergartners and seventh graders must show proof of immunizations.

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Monday WAS the first day of school for kids in Oakland. Hundreds of them were expected to be sent home.

“There could be a few hundred kids that are not immunized and so we’ll be encouraging them as quickly as possible to get out there,” said Oakland Unified School District John Sasaki. “Their parents may try to drop them off and we’ll have to turn them away.”

Young children who got their personal belief exemptions approved before January 2016, will be grandfathered in. According to the new law, they still must get immunized when they reach seventh grade.