The Disneyland measles outbreak and subsequent debate over vaccination has largely faded from the headlines, but in its wake, states around the country are considering tightening up their immunization requirements.

At least 14 states have introduced bills that would make it harder for parents to gain certain types of vaccination exemptions.

While activity around vaccination law isn't unusual in state legislatures, the number of bills introduced in just a matter of weeks is striking, and some observers say the bills may have more traction, given all the attention from the measles outbreak this year. 

"It’s all spurred on by the measles outbreak; it’s causing policymakers to give another look at what their state can do" to tighten vaccination requirements, said Diane Peterson, associate director for immunization programs at the Immunization Action Coalition, a pro-immunization group.

In her home state of Minnesota, Peterson said, she's been working on a bill that would require parents who want a personal-belief exemption to get a signature from a health-care professional that they have received information on the risks and benefits of immunization to their child and the community. They would need to renew the exemption when their child enters seventh grade.

"It shouldn’t be easier to get your child into school without vaccinations than with vaccinations," Peterson said.

The bill had been in the works for several years, Peterson said, but they had been waiting for the right "legislative climate." The measles outbreak, and the rash of headlines that accompanied it, provided that climate. "All of a sudden everything went kind of crazy for a while."

But at least one expert believes that the problem with many of these proposed laws—which he sees as essentially "showboating" in the wake of media hysteria—is that they focus on the wrong issue. Rather than using scarce resources to make waivers harder to obtain, states should focus on helping reach the 20 percent or so of undervaccinated children who are undervaccinated due to their lack of access to health-care, who don't have either waivers or their vaccinations, said Mark Largent, a historian at Michigan State University in East Lansing and the author of Vaccine: The Debate in Modern America.

"There’s a lot of smoke but not a lot of fire, because reality is that things are better than they have been," Largent said, noting that rates both for vaccination compliance and waivers are at an all-time high. Things like parental-education requirements are "a monstrously large unfunded mandate," Largent says, that gives very little return.

Among the bills that have been introduced, some, including bills in California, Maine, and Washington, would remove the "philosophical belief" exemption from vaccinating. Oregon, Maryland, Vermont, Texas, Oklahoma, and Rhode Island have bills that would also do away with religious exemptions, while Illinois and New Mexico are looking to restrict religious exemptions (requiring an official of a recognized religion to attest to the objection). A separate Vermont bill would require all teachers, administrators, and school staff to be fully vaccinated unless they have a medical exemption.

Other bills, like the one in Minnesota, would make the process of getting an exemption tougher—following in the wake of states like California and Michigan that have also started requiring health official signatures on exemptions and parental-education requirements. Arizona has introduced a bill that would require schools to post their immunization rates on their website, while a bill in Missouri would require principals to send letters home to parents notifying them if there are any nonimmunized students in the school.

It's impossible to know at this point whether the bills will become law, but people who follow the issue, on both sides of the debate, say that there's more traction than normal and a lot of public enthusiasm for tightening vaccine requirements.

"I do think we’re in danger here of having a country that is committed to forced vaccination," said Barbara Loe Fisher, cofounder and president of the National Vaccine Information Center, which lobbies for exemptions and for parental choice around vaccines. "We consider this an assault on both civil liberties and human rights."

Advocates for tougher vaccine laws say that the pendulum has swung too far toward allowing exemptions, lessening herd immunity and endangering babies too young to be vaccinated and those who can't be vaccinated for medical reasons. Advocates for exemptions argue that the principle of informed consent is a basic right when it comes to pharmaceuticals, and say the idea of forced vaccination smacks of utilitarianism, sacrificing the few for the many. Ms. Fisher points out that there is no product liability for vaccines, essentially indemnifying pharmaceutical companies from any adverse reactions, making such a lack of personal liberty even more problematic.

Measles has been considered eliminated from the U.S. since 2000 (meaning that year-round, endemic transmission doesn't occur), but saw a spike in the number of cases (644) last year, mostly linked to travelers returning from the Philippines and an outbreak in Ohio Amish communities. This year, the outbreak linked to Disneyland—which the Centers for Disease Control believes originated from an overseas traveler—has garnered huge media attention and sparked repeated calls among some officials for tighter mandatory requirements. According to the latest CDC data, between December 28 and February 27, 170 people in 17 states were reported to have been diagnosed with measles.

Looking at the debate from a public-policy perspective rather than strictly a medical perspective means considering factors like personal liberty and parental authority along with what science and medicine suggest, Largent said. He cites a Pediatrics study, published Monday, which showed that 93 percent of doctors had been asked at least once in any given month to delay vaccines, while about 20 percent said that more than 10 percent of parents asked to delay vaccines. The American Academy of Pediatrics advises doctors to keep such patients in their practice and work with them, hoping they'll eventually get immunizations.

"We’re grossly overstating the risk of a small percentage of people choosing to not fully vaccinate their kid," Largent said. "It's easier to go after hippies and libertarians and not focus on the fact that the best way to solve this problem is to create a collaborative relationship between physicians and patients. . . . We’re discussing it as pro-vaccinator versus anti-vaccinator, when 40 percent of the American public is in the middle."