Maine’s school-required vaccination rate has gone from one of the nation’s worst to one of the best over the past two years, a reversal that followed the state’s elimination of religious and philosophic exemptions.

New state data shows the percentage of students entering kindergarten who have received childhood vaccines increased substantially during the 2022-23 school year, the second-year rates have improved.

Exemptions from the childhood vaccine mandates are still permitted for medical reasons, but students with those exemptions represented 0.8% of Maine’s population of about 11,700 kindergarten students, according to the Maine Centers for Disease Control and Prevention, compared to 1.5% the previous year. The state’s opt-out rate for all exemptions was 4.5% in 2020-21, the last year before the new law took effect.

Dr. Laura Blaisdell, president of the Maine chapter of the American Academy of Pediatrics, said that “when you see this sort of decrease in exemption rates, and increase in vaccine protection in Maine, it’s a success story of unparalleled dimensions.”

The U.S. CDC uses kindergarten vaccination rates as a benchmark to compare states’ immunization rates for preventable diseases such as measles, mumps, polio, pertussis and chickenpox.

Before the law was implemented during the 2021-22 school year, Maine typically had one of the worst opt-out rates in the nation for school-required vaccines, putting the state at risk for outbreaks of infectious diseases and compromising the safety of immune-compromised students. The opt-out rate varied, but fluctuated between about 4% and 6% per year for exemptions, the bulk of which were for religious or philosophical reasons.

Now Maine has one of the best school vaccination rates in the nation given that its opt-out rate is less than half of the national average. About 2% of children are forgoing vaccines nationwide. Detailed state-by-state comparisons for the 2022-23 school year won’t be available until this fall.  

In addition to Maine, California, New York and Connecticut have approved laws to forbid non-medical opt-outs in recent years, and West Virginia and Mississippi have longstanding laws against non-medical opt-outs. Both California and New York approved the more restrictive school vaccine laws partly in response to measles outbreaks.

An unknown number of the students who had vaccine exemptions in Maine before the law change are now homeschooled and are not subject to the mandate.

The sharp drop in the vaccine exemption rate followed a big increase in the number of students who are homeschooled in Maine, part of a national response to the COVID-19 pandemic. The number of homeschooled students in Maine jumped 78% in the 2020-21 school year, increasing to 12,044 students from 6,775 students in the 2019-20 school year. The number declined roughly 10% to 10,871 students in 2021-22. Data was not yet available for the last school year.

For highly infectious diseases, even a few percentage points of vaccination coverage can make a difference in preventing outbreaks in a school community. Also, before the new law went into effect two years ago, vaccine opt-out rates were not distributed evenly, with some schools having opt-out rates of 20% to 30% or higher, leaving those schools especially vulnerable to an outbreak.

One school that often had one of the lowest kindergarten vaccination rates in the state before the law went into effect – Fiddlehead School of Arts and Sciences in Gray – went from an opt-out rate of 35% in 2020-21 to having no kindergartners opting out for 2022-23.

Dr. Linda Sanborn, a retired family doctor and former Democratic state lawmaker who co-sponsored the bill that became law in 2019, said she feels an “extreme sense of satisfaction” to see vaccination rates improve.

“It’s going to make a difference in protecting kids, and keeping our students free of preventable diseases,” Sanborn said.

Experts such as Blaisdell have credited Maine’s new law with helping to improve the state’s pertussis rates, which used to be among the nation’s highest.

In 2019, the last year before the pandemic, Maine reported the nation’s second-highest per capita rate of pertussis – also known as whooping cough – with 28.49 cases per 100,000 population. The national average was 5.67 cases per 100,000. In 2022, Maine was on track to record roughly seven cases per 100,000 through November, the latest data available from the Maine CDC. Final national data for 2022 is not yet available, although interim data shows less than 1 case per 100,000 nationally.

Anti-vaccine advocates continue to try to repeal the vaccination law, including an attempt in the current legislative session.

During a public hearing before lawmakers in April, anti-vaccine advocates repeatedly pushed debunked conspiracy theories about childhood vaccinations, such as that vaccines cause autism. Many of the same falsehoods have been touted during national debates about vaccines, including misleading information about the COVID-19 vaccines, which are not school-required. Most recently, Robert F. Kennedy Jr., an anti-vaccine advocate who is running for the 2024 Democratic presidential nomination, espoused a number of debunked vaccine conspiracy theories during an appearance on Joe Rogan’s podcast.

Maine’s House and Senate voted down the latest effort to repeal the law and restore the religious and philosophical exemptions.

A March 2020 statewide referendum that would have repealed the law also failed, with Maine voters supporting vaccination 73% to 27%.

Northe Saunders, a member of Maine Families for Vaccines, an advocacy group in favor of continuing to prohibit exemptions for non-medical reasons, expects efforts to repeal the bill will continue, but that lawmakers should be reminded that the overwhelming majority of voters support vaccines.

“We’re proud and excited Maine has become a leader in public health, but we need to remain vigilant and make sure we don’t go backwards,” Saunders said.