MMR Vaccination Rates by State: Which States Are Below the Herd Immunity Threshold?

39 States Fall Below the Measles Herd Immunity Threshold

For measles to stop spreading in a community, at least 95% of the population needs to be vaccinated with the MMR (measles, mumps, and rubella) vaccine. This is called herd immunity.

As of the latest CDC SchoolVaxView data, 39 out of 51 states and DC have kindergarten MMR coverage below 95%. The national average sits at just 91.5%.

This matters because every percentage point below 95% creates pockets of vulnerability where measles can take hold — which is exactly what we’re seeing with the 2026 outbreaks.

Check Your State’s MMR Rate

You can look up your state’s exact coverage rate on our MMR coverage map. Each state page shows:

• Current kindergarten MMR vaccination rate
• Whether your state meets the 95% threshold
• How your state compares to neighbors
• Historical trend data

Some of the states with the lowest MMR coverage rates include Idaho, Alaska, and Wisconsin — all well below the national average.

Why Kindergarten Rates Matter

The CDC’s SchoolVaxView survey specifically tracks vaccination rates among children entering kindergarten. This is a critical metric because:

1. It reflects recent parental decisions, not historical trends
2. Schools are where measles spreads fastest among children
3. It’s the most complete vaccination dataset — school entry requirements mean nearly all children are counted

When a state’s kindergarten MMR rate drops below 95%, it signals that enough children are unvaccinated to sustain a measles outbreak if the virus is introduced.

The Connection to Current Measles Outbreaks

The pattern in 2026 is clear: states with the most measles cases tend to have areas where MMR coverage has dipped. You can see this relationship by comparing our measles case tracker with the MMR coverage map.

This doesn’t mean every low-coverage state will have an outbreak. Measles needs to be introduced (usually by an international traveler). But when it arrives in an under-vaccinated community, it spreads rapidly — one infected person can transmit measles to 12-18 others.

What You Can Do

• Check your state’s rate on our MMR coverage dashboard
• Verify your family’s vaccination status — most people need two MMR doses
• Talk to your pediatrician if you have questions about the vaccine schedule
• Stay informed — we update our data weekly from CDC sources

About This Data

Our MMR coverage data comes from the CDC’s SchoolVaxView survey, which collects kindergarten vaccination rates from all 50 states and DC. The most recent data reflects the current school year. For methodology details, see our data sources page.

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Updated annually when new SchoolVaxView data is released. Last update: March 25, 2026.