California saw a surge in medical exemptions to school-required vaccinations after it passed a law in 2015 that is similar to the bill Maine Gov. Janet Mills signed last week banning all non-medical exemptions.

Parents who wanted to avoid school-required vaccines for their children exploited a loophole in the California law by finding doctors who were willing to grant medical exemptions under false pretenses, according to state health officials and news reports. Medical exemptions tripled after the law went into effect.

In Maine, public health advocates point out that California’s vaccination coverage is still vastly greater than before the law passed, and they say Maine may not experience the same implementation problems as California.

Maine joins California, West Virginia and Mississippi as the only states to ban all non-medical exemptions for vaccines that are required to attend school. Maine had permitted parents to forgo vaccines for their children by signing a form objecting on philosophic or religious grounds. Maine’s poor vaccination coverage among students entering kindergarten, and sky-high rates of pertussis, helped spur passage of the bill over the objections of some lawmakers, who claimed the measure violates parental rights.

Meanwhile, measles has come back nationally, spread by unvaccinated people, according to the U.S. Centers for Disease Control and Prevention. Measles is at its highest level in 25 years, as the U.S. CDC reports 940 measles cases in 26 states, with many of the cases in New York City and Washington state. Maine has reported one measles case.

A measles outbreak that started in Disneyland in 2014 prompted the California law that ended non-medical exemptions. Since then, California’s vaccination coverage has improved.

However, some parents are bypassing the law by obtaining medical exemptions from doctors willing to grant them for unjustifiable reasons – such as asthma and diabetes, according to news reports. Medical exemptions for vaccines are typically granted for children who have severely compromised immune systems, such as students with leukemia.

After the law went into effect, medical exemptions in California more than tripled, from 0.2 percent in 2015-16 to 0.7 percent currently, according to state health statistics. Dozens of California schools reported very high rates of medical exemptions – 20 percent or higher – which was statistically improbable.

Maine’s law will be implemented for the 2021-22 school year, giving health officials time to iron out the details.

Peter Michaud, general counsel for the Maine Medical Association, which helped draft the language for the law, said Maine and California are very different states, so implementation may not follow the same path.

“We shouldn’t start with the presumption that the medical providers can’t do this properly,” Michaud said. “Let’s see how this goes first.”

In California, the state Legislature is considering a bill to clamp down on false medical exemptions by requiring medical exemptions to be reviewed by the state. State officials in California have estimated that 40 percent of medical exemptions would be rejected if there were a state review process.

Maine’s new law – which cleared the state Senate by one vote – spells out that the Maine Department of Health and Human Services is barred from reviewing medical exemptions.

Michaud said that any medical provider granting unwarranted exemptions – in Maine exemptions can be written by doctors, nurse practitioners and physician’s assistants – would be subject to license discipline. He said that school nurses noticing questionable practices – such as a number of medical exemptions granted for dubious reasons – could refer the cases to state licensing boards.

California physicians also could be disciplined by state licensing boards for improper medical exemptions, but very few have been disciplined. In one prominent sanctioning, Dr. Bob Sears – a California pediatrician who promotes a controversial “alternative vaccine schedule” that has been refuted by the U.S. Centers for Disease Control and Prevention for not being based on sound scientific reasoning – had his license suspended for granting a questionable medical exemption.

Still, health advocates point out that California’s vaccine coverage has improved significantly. In the years before the law went into effect, California’s kindergarten opt-out rate was about 3 percent. Now, it’s 0.7 percent.

Maine’s non-medical opt-out rate for kindergartners was 5.6 percent in 2018-19, alarming public health officials.

Caitlin Gilmet, with Maine Families for Vaccines, a grassroots parents’ group, said once the law goes into effect in 2021, vaccine coverage will be much better.

“Herd immunity is a numbers game,” Gilmet said. “The real hardline folks who are against vaccines will always find a way to not vaccinate.”

Herd immunity – the protection offered to the immune compromised and those too young to get vaccines – starts to wane for some diseases when less than 95 percent of the community is vaccinated.

The kindergarten vaccination rate for the measles, mumps and rubella vaccine was 93.8 percent in the current school year, according to Maine state statistics. California’s MMR vaccination rate for kindergartners was 93 percent in 2014, when the Disneyland measles outbreak occurred, sickening 110 people with the infectious disease.

“Herd immunity occurs when a high percentage of a community is immune to a disease through vaccination and/or prior illness, making the spread of disease from person to person unlikely, even among unvaccinated individuals. Currently, 172 of 341 total kindergarten classes fall below this 95 percent threshold,” the Maine CDC said in a statement in April.

Jackie Farwell, Maine DHHS spokeswoman, when asked about California’s experience, could not offer any specifics to how Maine’s law would be implemented because the bulk of the implementation work has yet to be done.

“Pursuant to the law, the department will begin the process of rulemaking in conjunction with the Maine Attorney General’s Office and the Maine Department of Education,” Farwell said in a statement.