US Measles Cases Top 4,000 in 45 States: Worst Since 1991

US measles cases have passed 4,000 for the first time in decades. The CDC measles data page, updated on 9 October 2026, shows 4,080 confirmed cases so far this year, as of 8 October. Infections have been confirmed in 45 states and the District of Columbia, and all but five states have reported at least one case.

That is already well above the 2,289 cases confirmed in all of 2025 and the 285 in 2024. This report sets out the numbers, the main hotspots, the disagreement over the death toll, who is getting sick, and what the figures cannot tell us.

US measles cases at a glance

• Total in 2026: 4,080 confirmed cases, up 192 in one week.
• Reach: 45 states and Washington, D.C.; the CDC page counts 47 reporting jurisdictions.
• Outbreaks: 42 new outbreaks this year, accounting for 96% of cases.
• Deaths: the CDC has recognised two in 2026; Pennsylvania officials report five.
• Vaccination status: about 95% of cases were unvaccinated or of unknown status.

How US measles cases compare with earlier years

The CDC counts only confirmed cases reported to it, so the true number is likely higher. Even so, the comparison is stark. By our calculation, the 4,080 cases in 2026 are about 78% more than the 2,289 in all of 2025, and about 14 times the 285 in 2024.

Reports say the last time the country had more cases in a year was 1991, when there were 9,643. On that measure, 2026 is about 42% of the 1991 total. The CDC page also lists 1,274 cases for 2019. These ratios are our own arithmetic from the published counts.

The weekly pace is also worth noting. An increase of 192 cases in a week works out to roughly 27 a day, by our calculation, though cases are reported in batches and the daily figure is only an average.

Where US measles cases are concentrated

A small number of states account for a large share. Pennsylvania has 1,105 cases for the year, including 142 added in the latest week. South Carolina has 670 and Utah 535. By our calculation, those three states together hold 2,310 cases, or about 57% of the national total.

• Pennsylvania: 1,105 cases; all but four were in unvaccinated people, according to reports.
• South Carolina: 670 cases, unchanged on the week.
• Utah: 535 cases, unchanged on the week.
• Wisconsin: 207 cases, unchanged on the week.
• Kentucky: 104 cases, up 10.
• New York: 103 cases in the CDC tally, up 19, after the state declared a measles emergency.
• Iowa: 39 cases, up 17.

The New York figure differs from the state’s own count, which was 108 through 3 October in the reports we saw. Federal and state tallies are updated on different schedules, so they often do not match. We cover that outbreak in more detail elsewhere on this site.

US measles cases and the death toll: two counts

Five measles-associated deaths have been confirmed in 2026, all in Pennsylvania, according to state health officials. The CDC has so far recognised two and says that number is subject to change. Pennsylvania’s governor has protested the CDC’s count. One reported death was an 18-year-old woman in Mifflin County who died in September from brain swelling caused by the virus.

We cannot settle the difference from the public data. Deaths are confirmed through review of clinical records and death certificates, and federal and state counts can diverge while that review is under way. For earlier coverage, see our reports on Pennsylvania’s additional measles-associated deaths and the Pennsylvania outbreak reaching 1,078 cases.

Who is getting sick: age and vaccination in US measles cases

Most cases are in people aged 19 and younger. About one in 10 children under 5 have been hospitalised, according to CDC data cited in reports. Roughly 95% of cases were unvaccinated or of unknown status, 2% had one MMR dose and 2% had the recommended two doses.

The CDC says one dose of the measles, mumps and rubella (MMR) vaccine is about 93% effective and two doses about 97% effective. A small share of vaccinated people can still be infected, but the pattern in 2026 is overwhelmingly one of unprotected people.

Why US measles cases keep rising

Measles is among the most contagious diseases known, and it needs very high community vaccination coverage to stay out. The CDC page shows kindergarten MMR coverage falling from 95.2% in the 2019–2020 school year to 92.4% in 2025–2026. By our calculation, that is a drop of 2.8 percentage points, and the CDC estimates it leaves about 280,000 kindergartners at risk.

Falling coverage tends to be uneven, with pockets of low vaccination inside states that look fine on average. Some public health specialists believe the country is on track to lose the measles elimination status it earned in 2000, according to reports. We could not confirm a formal determination, and the criteria involve continuous transmission over time.

The federal response to US measles cases

The federal government has offered states more money to fight measles, according to reports. The US Department of Health and Human Services has also announced a separate push on vaccine injuries, including a new clinic and work to strengthen a database that tracks problems reported after vaccination. Health Secretary Robert F. Kennedy Jr. said: “We must listen to patients and families who report vaccine injuries – not dismiss or gaslight them.”

Public health experts have raised concern that falling immunisation rates and the measles resurgence sit alongside policy changes at HHS, a point made in coverage of the announcement. We report both facts and leave the wider policy debate to readers.

What the US measles cases data cannot tell us

• They cover confirmed cases only. Dr. Peter Chin-Hong said the official count likely understates the true number because many families with cases were never tested.
• They do not show probable cases, which some states count separately.
• Hospitalisation, age and vaccination breakdowns for 2026 are partial in the sources we reviewed.
• Weekly changes depend on reporting schedules, not only on new infections.

Our assessment of US measles cases

In our assessment, the 4,000 mark matters less as a round number than as a signal that the outbreaks are not burning out. Three states account for most cases, but new outbreaks keep appearing, and a lower vaccination rate in kindergartners is a slow-moving cause that will not reverse quickly. The most useful local response is simple: check that children and adults have two documented MMR doses.

For general information on measles, see the Centers for Disease Control and Prevention (CDC) and the World Health Organization, or browse more pharmaceutical news.

What to watch next for US measles cases

• The CDC’s next weekly update and whether the weekly rise stays near 190.
• Any change to the CDC’s count of measles deaths.
• Outcomes of state emergency measures, including in New York.
• Kindergarten vaccination data for the next school year.

Frequently asked questions

How many US measles cases are there in 2026?

The CDC reports 4,080 confirmed cases as of 8 October 2026, in 45 states and Washington, D.C.

Which state has the most measles cases?

Pennsylvania, with 1,105 cases, followed by South Carolina with 670 and Utah with 535.

How many people have died of measles in 2026?

The CDC has recognised two deaths. Pennsylvania officials report five confirmed deaths.

How effective is the MMR vaccine?

About 93% after one dose and 97% after two doses, according to the CDC.

Is this the most US measles cases in decades?

Yes. Reports say the last year with more cases was 1991, when there were 9,643.

How we reported this: we relied on the CDC measles data page updated on 9 October 2026 and on public reports of the CDC weekly figures and state statements. State counts can differ from federal counts. Figures labelled as ours are our own calculations. Last updated: 10 October 2026. This article is news reporting and not medical advice.