Is Your Kindergartner Protected as Measles Surges?
Two on-time doses of MMR give your child about 97% lifetime protection against measles, and that individual protection matters more this year than it has in a generation. National kindergarten coverage has slipped for a sixth straight year. Exemptions cluster in specific schools, and US measles cases have already passed 2,400. Your own child's schedule is still the piece you control.
Kindergarten MMR coverage fell to about 92.4% for the 2025-26 school year. Measles needs roughly 95% coverage to stop spreading, and only ten states still clear that bar. About 93% of this year's cases are in people who were unvaccinated or of unknown status. The vaccine is still doing its job. Enough of the people around your child are no longer doing theirs.
Where the wall has thinned
The national figure hides what a parent actually cares about: the classroom your child sits in. Exemptions now clear 4% nationally. Twenty-four states are above 5%, and eleven are above 7%. Once a school passes 5% exempt, it can't reach 95% coverage even if every non-exempt child is fully vaccinated. And exemptions cluster. Two kindergartens in the same district can be a few percentage points apart on paper and a world apart in outbreak risk, because vaccine refusal groups by school, neighborhood, and social network.
The 2008 San Diego outbreak showed how this plays out. An intentionally unvaccinated child brought measles home from Europe, and all 11 secondary infections were in other unvaccinated children, even though the city as a whole had roughly 95% two-dose coverage. The same pattern is running at larger scale now.
Measles is behaving accordingly
An outbreak seeded in West Texas and moving through undervaccinated religious communities has driven most of this year's US cases, spreading into New Mexico, Oklahoma, and across the borders into Canada and Mexico. About 7% of confirmed US cases have needed hospitalization, and people under 20 have made up more than 60% of infections. The Pan American Health Organization has flagged the US as 'sustained elimination with major concerns,' and the Region of the Americas lost its measles-free status in late 2025 after Canada was found to have sustained transmission for more than 12 months. If US transmission continues, a formal PAHO review in November 2026 could strip the elimination status the country has held since 2000.
What two doses of MMR actually do
The MMR series is one of the most studied interventions in pediatrics. One dose given at 12 months or later is about 92% effective against measles infection. A second dose lifts that to roughly 94 to 99%, with only slow decay across decades. In a Colorado elementary school outbreak used as a natural experiment, the attack rate was 44% in unvaccinated children, 3% in children who had received one dose, and zero in children who had received both.
The safety record is unusually complete. Large studies, including a Danish national cohort of more than half a million children, have found no association between MMR and autism. The most consistent side effect is a small, short-lived rise in febrile seizures 1 to 2 weeks after the first dose, roughly 25 to 34 extra cases per 100,000 vaccinated children, which does not translate into higher long-term rates of epilepsy or neurodevelopmental problems.
| Outcome | With two doses of MMR | With measles infection in an unvaccinated child |
|---|---|---|
| Protection from measles | About 97% effective, durable for decades | No protection |
| Pneumonia | Not a known vaccine effect | About 1 in 20 cases |
| Encephalitis (brain inflammation) | Not a known vaccine effect | About 1 in 1,000 cases |
| Febrile seizure in the 1-2 weeks after dose 1 | About 25 to 34 extra per 100,000 children, no long-term effects | Also elevated by the high fever measles produces |
| Subacute sclerosing panencephalitis (a delayed, always-fatal brain disease) | Not a known vaccine effect | As high as 1 in 609 when infection occurs before 12 months |
| Death | Not a known effect in healthy children | About 1 to 3 per 1,000 cases in high-income settings |
What actually protects your kindergartner
The choice that reliably protects your child is finishing the two-dose series on schedule: the first dose at 12 to 15 months, the second at 4 to 6 years. Catch-up doses for a child who is behind can be given at least 28 days apart. For an infant aged 6 to 11 months who will travel internationally or lives in an active outbreak area, an early dose is standard practice, and it does not replace the two later doses. The number that best describes the classroom your kindergartner will be in is your specific school or district's exemption rate, not the state average.
The vaccine hasn't changed. The world around it has. Two on-time MMR doses still give roughly 97% protection with a safety record built on millions of children. In a year when measles is spreading faster than it has in a generation, that on-schedule decision, checked against your own school's numbers, is the part of herd immunity you actually control.