The Disneyland measles outbreak, in which at least 84 people in 14 states have contracted the disease, should be a wake-up call for New York City.

Thanks to pockets of anti-vaccinators exploiting loopholes in state policy, particularly on the Upper East Side, outbreaks here are inevitable, health experts say.

NYC public schools require vaccinations for all students and grant religious and medical exceptions rarely. Only 0.19 percent of public school students received the religious exemption this year, while 0.01 percent were granted a medical exemption.

But private schools may accept nearly any medical and religious exception they deem worthy, and more than 90 private schools in the city report vaccination rates for their children below the recommended 95 percent last year. For 24 of those schools, the rates dipped below 80 percent.

At the Rudolf Steiner School on East 79th Street, which is part of a global system of schools founded by the decidedly anti-vaccination philosopher of the same name, only 76 percent of students have been fully vaccinated.

School officials are quick to point out that Rudolf Steiner is in compliance with state reporting laws. But that’s only because it’s provided doctor’s notes for those 24 percent of unvaccinated students, such as saying that an allergy to eggs prevents them from being given shots.

Besides the improbability of such a high rate of aversion to eggs, such allergies are not allowed as an excuse for public-school students.

Even those parents whose children are vaccinated at Rudolf Steiner told The Post that the decision should be a personal choice, not a government directive.

“I think at most of the progressive schools, whether they are public or otherwise, a lot of families feel that they have that right,” the mother of a fully vaccinated Rudolf Steiner kindergartner said.

But parents aren’t just making decisions for themselves. While the measles vaccine is powerful, two doses are still only 97 percent effective against infection.

This means that an unlucky 3 percent of people who get vaccinated won’t receive the full benefit because either their bodies won’t produce enough antibodies or the ones it does produce are ineffective.

Three percent doesn’t sound like much until you remember that at Disneyland, at least five of the stricken were fully vaccinated.

This highlights the importance of what epidemiologists refer to as “herd immunity,” a virtual “human wall” that prevents a disease from gaining a foothold in the community.

If enough of us are vaccinated, even those who are not eligible for certain vaccines — such as infants, pregnant women and people whose immune systems are compromised — get some protection because the spread of the disease is contained, said Dr. Ann E. Kurth, associate dean for research at New York University’s Global Institute of Public Health.

Herd immunity only kicks in if at least 95 percent of the population at large is vaccinated.

Nor is measles a “harmless” disease. It’s a serious and sometimes deadly upper respiratory disease that also causes rash and fever. You can catch it just by being in a room where a person who had the disease breathed — forget coughed or sneezed, just breathed. And it can hang in the air for up to two hours after that infected person has left the room.

“There are these communities being formed that take on their own logic,” Kurth said of the anti-vaccination movement. “Parents want to protect their children and the message has to break through that vaccinations are the way to protect your children.”

“You might think, given the media coverage, that the exemption movement is huge. It isn’t, but these hot spots are at risk, and we should be concerned,” said Brendan Nyhan, a political science professor at Dartmouth University who published a study in the journal Pediatrics last year that analyzed the effectiveness of messaging in the vaccination debate. “If these exemptions keep ticking up, we could have a serious problem.”

Public health officials said they constantly work with private schools, auditing them and educating them about the city’s exhaustive immunization-records registry, which collects data that can help contain outbreaks.

Parents want to protect their children and the message has to break through that vaccinations are the way to protect your children. - Dr. Ann E. Kurth, associate dean for research at NYU’s Global Institute of Public Health

“When we look at schools, we look not only at compliance and percentage of kids covered, but the number of children who are excludable,” said Dr. Jane Zucker, assistant commissioner for the New York City Health Department’s immunization bureau. “You can have a large school with high compliance but still have a lot of unimmunized kids — and that’s a risk.”

Just 15 years ago, health officials in the United States declared homegrown measles dead. A successful childhood vaccination program had eliminated endemic cases of a disease that had once infected 3 million people in the US every year, killing 500.

The disease still ravages many in the developing world where access to vaccines are limited, but people in the US and Europe were looking at measles in the rearview mirror.

Unfortunately, around that same time, British surgeon Andrew Wakefield, published a fake study erroneously linking the MMR vaccine to autism. After convincing such unimpeachable public-health experts as Playboy Playmate Jenny McCarthy, Wakefield’s junk study gained supporters and corroded decades of progress, as evidenced by the latest outbreak.

Even after Wakefield’s study was discredited and his British medical license revoked, the fantasy that vaccines pose more harm than good persists among pockets of parents.

At Rudolf Steiner, most parents refused to discuss the topic, but one father whose third-grade daughter is fully vaccinated said he doesn’t completely trust the medical community’s assertions that vaccines are the best tools to protect children against disease.

“Doctors, maybe they have a thing where they are being encouraged by drug companies and pharmaceuticals to say a certain thing,” he said.

Spare New York introducing restrictions on the vaccination exceptions private schools are allowed to accept, experts say outbreaks like the recent one at Disneyland will do little to sway anti-vaxxers.

In fact, studies have found that the more people are confronted with facts that counter their beliefs, the more entrenched in those beliefs people become, Nyhan said.

Kurth suggests another approach: Appealing to parents’ sense of empathy.

“Vaccinations are part of the social contract,” she said. “I not only get my children vaccinated to protect them but because it will protect the broader community against this big threat.”

In other words, when it comes to highly communicable diseases and our obligation to contain them, it’s a small world after all.

Additional reporting by Amber Jamieson.