Internet Explorer 11 is not supported

For optimal browsing, we recommend Chrome, Firefox or Safari browsers.

The Vaccination-Exemption Challenge

Aiming to make them more difficult to get, many states are considering strengthening their laws. There's evidence about what makes for a good one.

Boy receiving a vaccine from a female doctor.
Remember the Disneyland measles outbreak that began in late 2014? With more parents opting not to vaccinate their kids over misplaced fears that vaccines are harmful or misperceptions that they aren't necessary, and more headline-grabbing outbreaks of diseases like measles and pertussis, it's no surprise that many states are considering strengthening their vaccine-exemption laws.

California sure did: A few months after Disneyland, it enacted Senate Bill 277, becoming the third state to offer no non-medical exemption option for parents who don't want to comply with school-entry immunization mandates. And what happened? While there have been fewer measles cases in the state, California experienced a startling 150 percent increase in medical exemptions last year.

Efforts to strengthen exemption laws aim to improve vaccine coverage rates of school-aged kids to minimize the risk of disease outbreaks and improve our collective "herd immunity." That's a good goal. But for state legislators, these efforts raise an important and difficult question: Is my state striking the right balance between protecting the public's health and preserving parental choice?

There's a good chance your state is among those debating new exemption policies: So far in 2017, at least 17 state legislatures have considered dozens of bills related to vaccine exemptions. Most of the proposals, as with California's SB 277, make exemptions more difficult to get. New York's Assembly Bill A3485 (in committee as this is written) prohibits taxpayers from claiming a tax deduction for a child not fully immunized.

These proposals anger anti-vaccine constituents concerned about parental rights and vaccine safety. As always with such a heated topic, politics and passions can get in the way of good policy based on good science. But there is good news: We have evidence about how to craft exemption policies that maximize health while preserving parental authority. For lawmakers drafting or voting on vaccination legislation, here is a primer on what we know and what we don't:

We know that the easier it is to get exemptions, the more parents choose to get them. We know that higher exemption rates are associated with more disease outbreaks. And, there's good evidence that requiring vaccine education or a health care provider's signature -- making exemptions harder to obtain -- can reduce exemptions (as happened in Washington state and under California's previous, less-restrictive exemption law).

But we don't know under exactly what conditions an additional education or signature requirement works. Simply requiring a parent to check a box on a form or speak with a health care provider is probably not enough to change behavior. On the other hand, some barriers to obtaining an exemption may actually reinforce anti-vaccine sentiment. Idaho's certificate of immunization exemption requires parents to write a brief statement explaining their opposition to having their child vaccinated. While this may deter some parents due to the hassle factor, the very act of articulating opposition to vaccination may reinforce existing beliefs.

And we really don't know the consequences of eliminating non-medical exemptions altogether. Will this simply drive more parents to seek a medical exemption even if not medically justified, as seems to have happened in California? (Some less-than-ethical doctors in California are taking advantage of parents' desires for an exemption and charging handsomely for it. That 150 percent increase in medical exemptions didn't happen because there suddenly were 150 percent more sick children.) California's elimination of non-medical exemptions is recent enough that we don't know much yet about its unintended consequences, such as parents deciding to home-school, move out of state or seek a medical exemption.

So how should a legislator think about good lawmaking. given what we know and don't know? Here are three factors to pay attention to:

• Make sure that complying with your state's immunization requirement is the easy, default choice for parents. Adding some hassle factor to obtain an exemption is OK.

• Make sure your exemption policy places minimal burden on schools and health care providers.

• Fully fund implementation of any laws, and ensure that school staff get adequate training and resources to ensure a smooth transition.

Vaccine mandates are an important component of protecting all children -- including those who for genuine medical reasons shouldn't be vaccinated -- from dangerous diseases. Remember that our collective herd immunity against these diseases is both a public good and a hard-won national asset.

Associate professor of nursing and health policy at the University of Pennsylvania
Special Projects