Measles math: Why vaccine mandates aren’t the answer
When it comes to measles, the United States has a problem. But it isn’t just a policy problem, it’s a math problem — even if everyone attending in-person school were vaccinated, we’d still fall short.
Measles cases have been reported in 38 states this year, and vaccination coverage rates are below the 95 percent threshold needed for community protection. We face a genuine public health crisis. The American Academy of Pediatrics (AAP) recently called for eliminating all non-medical vaccine exemptions, arguing this will get us there.
It won’t, and it might make the problem worse.
National measles coverage rates for kids attending in-person kindergarten are at 92.7 percent. But only 92-94 percent of children attend school in person, leaving about 6-8 percent of kids in homeschooling or online alternatives (not captured in these numbers are newer options like pods, microschools and umbrella-school pathways, all of which would only raise the out-of-system percentage further).
The math for mandates doesn’t add up. Even if all exemptions were removed, national coverage from that group alone would still be below the herd immunity threshold, and that’s assuming that no families balk at the new restrictions and pull their kids from public school.
Our 95 percent community-protection goal depends on vaccinating all kids, not just the ones in classrooms. Most children outside of traditional schools aren’t cloistered; they go to religious services, play sports and engage in public life. Many of them are vaccinated now, but overall, their rates are lower and more variable. Getting to 95 percent means we have to find ways to reach more of them.
It is unfair to blame these families for our current crisis. We have built vaccine policies that treat all vaccines as equally necessary and, though nominally only “recommending” them, withhold school access to those deemed noncompliant. Vaccines are important, but they aren’t all equally important, and they aren’t all equally necessary. Our all-or-nothing approach forces parents who might accept measles vaccination to comply with the full schedule or leave the system entirely.
Even more concerning: tighter mandates risk pushing even more families out.
When California eliminated personal belief exemptions in 2016, MMR uptake among enrolled kindergarteners rose. (Measles is only available as part of a combination MMR shot.) However, the number of children in the “no immunization data” category — primarily those not captured in public school counts — doubled. Compliance went up, but only among those who stayed in the system.
A supporter of the AAP statement acknowledged that this approach might lead to “excluding a child from public education,” and though admitting that this “does have problems,” insisted that “other educational opportunities are available.” This is flippant, potentially harmful to children, and self-defeating to their own coverage objectives. Have we really not learned the lessons of the severe and lasting harms caused by prolonged COVID-19 school closures?
Mandate-based strategies were designed in an era of limited educational alternatives. It was easier to bully parents into submission — comply or get out. But lockdowns and technology expanded what education could look like, creating new forms that preserve socialization while respecting parental decision-making.
How could we do better? Focus the vaccine schedule on truly community-protective vaccines, allow for flexibility in timing, and bring back single shots that just cover measles as an alternative to the combined MMR vaccine for those children who are immunocompromised and more at risk from vaccines. (Yes, vaccines, just like every medical treatment, will have adverse effects for some sub-population of patients — something we shouldn’t ignore.) There is no one silver bullet, because parents opt out of in-person schools and vaccine schedules for many different reasons.
Restricting exemptions will never get us where we need to be. Our only hope is actively working with the families whose participation can’t be coerced. We have to engage in shared decision-making and really mean it.
There are authorities who might worry that flexibility would place vulnerable groups at risk. But that potential risk must be balanced against another math problem. If the out-of-system population grows even a little more, if it exceeds 10 percent, no combination of approaches will get us back to a level that supports community protection.
We have built a system that pushes away the very families it needs to reach. We can continue to insist that the problem is we haven’t been strict enough, or we can address the reality of our current educational landscape.
The choice isn't between perfect safety and risk — it’s about not doubling down on a failed strategy. It’s about learning from other countries, and trying new ideas that will meet parents where they are. This isn’t about being pro- or anti-vax. This is just math.
Monique Yohanan, MD, MPH, is a senior fellow at Independent Women, a physician executive and healthcare innovation leader, and chief medical officer at Adia Healthcare.
