(AP) — Hundreds of critics of mandatory vaccines were in Sacramento Wednesday opposing 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 planned to pack the first legislative hearing on a bill that proponents said would stem bogus exemptions granted in many cases by doctors who are paid to excuse students from vaccinations.

Democratic Sen. Richard Pan of Sacramento said his legislation would give state health officials the tools they need to prevent outbreaks of vaccine-preventable diseases like measles, which in the first four months of the year have reached 23 confirmed cases in California.

An Associated Press count shows this year’s national measles tally is the highest since 1994.

Pan’s bill is one of a number of efforts by state legislatures to address measles outbreaks. Washington state lawmakers voted Tuesday to remove parents’ ability to claim a personal or philosophical exemption from vaccinating their children for measles, although medical and religious exemptions will remain.

Opponents of Pan’s bill, including members of parental rights and religious groups, doctors and alternative healthcare practitioners, said the measure strips away parents’ rights and isn’t necessary to prevent outbreaks.

“Now they’re going after us parents whose children have been injured by vaccines, and doctors as well,” said Christina Mecklenburg, who flew in from her Orange County home. “We can’t remain silent any more. Too many of our children are being injured.”

She said a vaccine last year left her now 2-year-old daughter, Hayden, cross-eyed with an ocular palsy that wouldn’t qualify for a medical exemption if Pan’s bill becomes law.

Critics are unlikely to derail the bill because Pan, a Sacramento pediatrician, is chairman of the Senate Health Committee considering his legislation.

He and other supporters said pockets of unvaccinated students are helping to spread measles outbreaks in California and elsewhere. Pan said a few unethical doctors are helping parents avoid vaccinating their children by selling medical exemptions through word of mouth or online advertising.

California ended non-medical immunization exemptions in 2016, but Pan’s bill would follow West Virginia’s lead in having public health officials rather than doctors decide who qualifies for medical exemptions. Doctors would certify that they examined the patient and then send the state health department the reason they are recommending the exemption.

State and county health officials could also revoke exemptions if they are found to be fraudulent or contradict federal immunization standards.

Federal guidelines say less than 1 percent of children should avoid vaccinations if they have a severe allergic reaction or impaired immunity such as from a liver problem, the HIV virus or chemotherapy.

The legislation would put decisions in the hands of a state bureaucrat who “has never laid eyes on my child,” said Catharine Layton, who flew in from her Southern California home. “It totally comes between the patient and doctor relationship, which is sacred.”

Layton said her now 5 ½-year-old son, Brennan, suffered a permanent brain injury after he was vaccinated at age 2.

“He’s pretty much unable to speak, he’s in diapers, he functions at the level of an 18-month-old. And prior to the vaccine he was healthy,” she said. Like Mecklenburg, she said she would home-school her children if Pan’s bill becomes law.

Statewide immunization rates increased to more than 95 percent after California abolished the personal belief exemption in 2016, enough to keep most outbreaks from spreading.

But health officials say the rate of medical exemptions has also tripled. It is still less than 1 percent of school children statewide, but advocates said more than half of students aren’t vaccinated in at least three California schools and 50 schools have exemption rates of at least 15 percent.

More than 100 doctors signed a letter calling Pan’s measure “an ill-advised bill that will have adverse impacts on our patients and their care” with a “one-size-fits-all” solution.

Pan’s office said some of the doctors are believed to be providing questionable exemptions, while the group noted that Pan has accepted tens of thousands of dollars in campaign contributions from the pharmaceutical industry.