By 5 November, the US had 5,182 confirmed measles cases in 2026, according to the Centers for Disease Control and Prevention (CDC). That provisional, still-rising count is the highest for any year since 1991 (9,643), more than twice 2025's 2,289, and more than all 4,485 cases of 2000–2024. On 10–13 November a Pan American Health Organization commission is reviewing whether the US has lost its measles elimination status, a question that turns on unbroken transmission, not case counts.
Measles cases reported to CDC per year, 1962–2026, log scale. 2025 and 2026 are provisional; 2026 is to 5 November. Source: CDC.
What these numbers are
The figures are confirmed cases that state and local health departments have notified to CDC, published on CDC's Measles Cases and Outbreaks page and updated weekly. Probable cases are left out. Each case is counted in the year of its rash onset, by epidemiological week, and the total includes 18 cases in international visitors to the US. CDC calls the 2025 and 2026 counts preliminary and subject to change.
The early years are not comparable with today. Before the vaccine arrived in 1963, CDC estimates that 3 to 4 million people in the US were infected each year; only a fraction were reported. The chart uses a log scale so that the 1960s and the 2020s fit on one chart: equal vertical distances represent equal ratios, and each gridline is ten times the one below. Case definitions and surveillance have changed over six decades, so the long series is of reported cases; CDC's older publications give slightly different figures for some early years.
Far ahead of 2025; recent weeks remain incomplete
Running total of confirmed cases by MMWR week of rash onset, 2024–2026. The shaded weeks, 43 and 44, are the most recent and the most likely to change. Source: CDC.
By week 44 (data to 5 November), 2026's running total was 3.1 times 2025's at the same point: 5,182 against 1,699. Week 44 ends on 7 November, but this snapshot includes reports only through noon on 5 November, and earlier weeks can also be revised. The two years differ in shape as well as size. In 2025, new cases slowed after the spring, to about 21 a week in weeks 27–42, from July to October. In 2026 they ran at about 220 a week in the eight weeks to 24 October.
The two latest weeks show 138 and 93 cases; the second runs only to 5 November. CDC counts cases by rash onset and calls the figures preliminary, so these weeks are the most likely to rise as reports arrive; they are not yet evidence of a slowdown.
More than a quarter of 2026's cases (1,385) came from outbreaks that began in 2025. CDC reports 43 new outbreaks in 2026, defined as three or more related cases, and 48 in 2025. In 2026, 96% of confirmed cases (4,993) were part of an outbreak.
Where the cases are
Confirmed cases among US residents by reporting jurisdiction, 2026 to 5 November (bars) and 2025 (ticks). CDC reports New York City separately from New York State. Source: CDC.
Cases are spread widely but concentrated in a few places. Of the 5,164 cases among US residents, 47 jurisdictions reported at least one, but four states account for 60%: Pennsylvania, South Carolina, Utah and Wisconsin. Pennsylvania alone has 1,476, against 16 in 2025. Texas, which had the most cases in 2025, 803, has 192 so far in 2026.
According to CDC's summary figures, 58% of 2026's cases are in people under 20, and 96% (a separate CDC figure) were unvaccinated or had an unknown vaccination status. CDC reports 562 people hospitalised, 11% of cases.
Fewer kindergartners vaccinated
MMR vaccination coverage among kindergartners by state and DC, school years 2009–10 to 2025–26; the number of states reporting varies by year. Source: CDC SchoolVaxView, via the CDC measles page.
CDC says that when more than 95% of a community is vaccinated, most people are protected. Nationally, it reports that MMR coverage among kindergartners fell from 95.2% in the 2019–20 school year to 92.4% in 2025–26, with about 280,000 kindergartners lacking documentation of completing the MMR series. Coverage measures documented completion of the kindergarten MMR series, generally two doses, rather than exemption status; exemptions can cover one or more vaccines and are not the complement of MMR coverage. These estimates concern kindergarten pupils, not whole-state populations. The state figures show the same drop: the unweighted median among reporting states and DC fell from 94.6% in 2019–20 to 91.5% in 2025–26, and the number below 95% rose from 28 of 48 reporting states in 2019–20 (DC did not report) to 39 of 49 reporting jurisdictions, 48 states plus DC, in 2025–26.
State averages do not line up neatly with state case counts. Idaho has the lowest coverage, 75.2%, and 4 cases in 2026. Utah (87.2%) and Wisconsin (85.1%) are below the median state, but Pennsylvania (92.7%) and South Carolina (93.4%), with the most cases, are above it. CDC notes that coverage can vary considerably at local level, and that pockets of unvaccinated people can exist in states with high coverage; outbreaks occur when measles reaches them. This data counts cases and coverage. It does not show what caused either. Under the heading "Why is there more measles activity?", CDC points to two things: kindergarten coverage that has fallen below the 95% target, "with much lower coverage in some communities", and more measles around the world, which means more chances for an unvaccinated traveller to bring it back.
What the elimination review decides
The US was declared to have eliminated measles in 2000, meaning, in CDC's words, that there had been no continuous spread of the disease for more than 12 months. PAHO, the World Health Organization's regional office for the Americas, defines the return of endemic measles as "a chain of measles virus transmission of the same genotype and lineage that continues uninterrupted for 12 months or more" in a country.
PAHO says the US assessment runs from the start of the outbreaks reported from 20 January 2025, and those in Mexico from 1 February 2025. A review was first set for 13 April 2026; PAHO moved it to the Regional Verification Commission's regular November meeting, citing the US health authorities' ongoing analysis, including complete viral genome sequencing. The commission is meeting on 10–13 November, looks at data for 2025 and the first half of 2026, and sends its recommendations to PAHO's Director, who communicates the classification to national authorities.
The decision turns on whether one chain of the virus kept spreading for a year, which needs genetic and field evidence, not on the number of cases. The counts in this post cannot answer it either way. There is a precedent: on 10 November 2025 PAHO announced that endemic transmission had been re-established in Canada, so the Americas lost their measles-free status. A country that loses the status can regain it by showing that endemic transmission has been interrupted for at least 12 months, PAHO said. We will update this post when PAHO announces the commission's conclusion.
How this was made
The data comes from the CDC files behind the Measles Cases and Outbreaks page, published on Friday 6 November 2026 with reports through noon on Thursday 5 November, and retrieved on 8 November 2026: yearly cases from 1962, weekly cases by rash onset from 2022, cases by state for 2024–2026, the age, vaccination, hospitalisation and death summary, and kindergarten MMR coverage by state. CDC's federal materials are generally in the public domain in the US, subject to exceptions CDC identifies; the data is available free on CDC's website, and its use here does not imply endorsement by CDC. PAHO announcements are cited and briefly quoted as context; no open licence is claimed for them. fetch.mjs downloads the files; calculate.mjs checks their hashes and writes annual, weekly, state and kindergarten coverage tables and every number in this post (statistics.json); us-measles-2026-make-charts.mjs builds the charts, and re-running it reproduces them exactly. The weekly, state and summary files each add up to CDC's annual totals. Method and choices: DATA.md; sources and hashes: PROVENANCE.md. From the download folder, run:
npm ci
node us-measles-2026-src/calculate.mjs
node us-measles-2026-make-charts.mjs
Source: Centers for Disease Control and Prevention.