SACRAMENTO, Calif. (AP) — Hundreds of opponents of mandatory vaccines are in Sacramento to oppose a California proposal to give state public health officials instead of local doctors the power to decide which children can skip their shots before attending school.

They plan to pack the first legislative hearing on a bill that proponents say would stem bogus exemptions granted in many cases by doctors who are paid to excuse students from vaccinations.

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Opponents say the measure removes parental rights.

Critics are unlikely to derail the bill, since Sacramento pediatrician Richard Pan is chairman of the health committee considering his legislation Wednesday.

Supporters say unvaccinated students are helping to spread measles outbreaks in California and elsewhere.

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Opponents also plan a rally to denounce what they term the “measles frenzy.”