Measles is back: why it matters

The resurgence in numbers

Measles is one of the most contagious diseases known: it spreads through the air, and a person can catch it simply by being in a room where an infected person has been. That is why the coverage threshold is so high — at least 95% of every community needs two doses to stop transmission.

The United States figures, kept strictly separate from the global ones, show how fast the return has been. As of 5 November 2026 the CDC recorded 5,182 confirmed cases across 47 jurisdictions plus 18 international visitors, with 43 outbreaks in 2026, 96% of cases outbreak-associated, 562 people hospitalised (11%) and 4 deaths (CDC, “Measles Cases and Outbreaks”, updated 6 November 2026). The 2025 full-year total was 2,289 cases. In the Americas region, the Pan American Health Organization recorded more than 22,000 confirmed cases and 39 deaths in the first half of 2026 across 17 countries and territories.

The coverage gap behind it

The driver is gaps in vaccination coverage. Globally, first-dose measles coverage (MCV1) was 84% and second-dose coverage (MCV2) 77% in 2025 (WHO/UNICEF WUENIC release, 15 July 2026) — both far short of the 95% threshold, and both essentially stalled. In 2025, 57 countries reported large or disruptive measles outbreaks. In the United States, kindergarten MMR coverage fell from 95.2% in 2019–20 to 92.4% in 2025–26, leaving about 280,000 kindergartners at risk (CDC). WHO has also reported that measles deaths fell 88% between 2000 and 2024, to an estimated 95,000 in 2024, and that measles vaccination has saved nearly 59 million lives since 2000 — progress that depends entirely on coverage staying high.

How vaccination protects communities

Two doses of MMR vaccine are 97% effective at preventing measles, and one dose is 93% effective (CDC). The protection is not only for the person vaccinated: when enough people in a community are protected, the virus finds fewer people to spread through, and people who cannot be vaccinated — very young babies, and people with certain medical conditions — are less likely to meet it at all. That community effect is why coverage is reported for whole populations, not just individuals, and why a fall from 95% to 92% in a school year matters out of proportion to the numbers.

The practical point is a check, not advice from this page: check MMR vaccination status with a health professional, especially before travel — CDC notes that rising measles activity worldwide means more chances of an unvaccinated person being infected abroad and bringing it home. Measles spreads through the air, so avoid close contact with a sick person and follow local health guidance. For the schedules themselves, see the vaccinations guides on this site and the Vaccination Directory for official sources.

The 2026 count, dated 5 November 2026

The CDC figure is 5,182 confirmed measles cases reported in the United States in 2026, as of 5 November 2026 (CDC, “Measles Cases and Outbreaks”, updated 6 November 2026). Of those, 5,164 were reported by 47 jurisdictions and 18 among international visitors. There have been 43 new outbreaks reported in 2026 — an outbreak is defined as three or more related cases — and 96% of confirmed cases (4,993 of 5,182) are outbreak-associated: 3,608 from outbreaks starting in 2026 and 1,385 from outbreaks that started in 2025. The CDC lists 4 deaths in 2026, and notes the number is subject to change.

For scale: the full-year 2025 total was 2,289 confirmed cases, with 48 outbreaks. The 2026 count passed that total months ago. This guide is the dated 2026 picture — the cases, the count, and the elimination review. The why behind the resurgence — the coverage gap, the 95% threshold, and how vaccination protects communities — is in the paired guide, Measles is back: why it matters.

Why CDC and state counts differ

Readers comparing the CDC count with a state health department’s count will often find two different numbers. That is expected, and the CDC page explains why.

First, the CDC publishes only confirmed cases that jurisdictions have notified to it, as of noon on Thursdays. It is aware of probable cases reported by jurisdictions, but does not include them in this count. States report on different schedules, include probable cases, and have the most up-to-date information about cases and outbreaks in their own jurisdictions — the CDC says so itself.

Second, deaths are counted differently from cases. The CDC now counts measles deaths using National Center for Health Statistics mortality data instead of state health department reports, and is working with the Council of State and Territorial Epidemiologists on a standardised death case definition, to classify deaths consistently across jurisdictions. The difference shows up in practice: Pennsylvania reported 5 deaths in state data in October 2026, against the CDC’s 2 at that time. The two counts measure different things on different timetables, and both are labelled preliminary and subject to change.

Elimination status: what it means and what is being decided

Measles was declared eliminated in the United States in 2000. Elimination means no endemic transmission for at least 12 months — new cases only arrive when someone contracts measles abroad and returns. It is a classification of transmission, not a claim that the virus has vanished: measles is still common in many parts of the world, and travellers bring it back every year.

Whether the United States still meets that definition is now being reviewed. The Pan American Health Organization’s Measles and Rubella Elimination Regional Monitoring and Re-Verification Commission meets on 10–13 November 2026 to review countries’ elimination status, using data from 2025 and the first half of 2026. The United States and Mexico reviews were moved from an April special session to the commission’s regular November meeting, because US authorities were still carrying out analysis, including complete viral genome sequencing.

The decision rests on genetics, not on how many people get sick. PAHO defines re-established endemic transmission as uninterrupted circulation of the same virus genotype and lineage for 12 months or more in a specific geographic area. For the United States, the analysis period starts on 20 January 2025, when the West Texas outbreak began. Experts cited in June 2026 argue that continuous transmission since the January 2025 West Texas outbreak meets the 12-month definition — but as of 7 November 2026, no formal determination exists. The commission does not announce a ruling on its own: it sends its recommendations to the PAHO Director, who formally communicates the classification to national authorities, so a public announcement may come after the meeting itself.

If the status is lost, what changes?

If the commission finds that the same viral strain circulated without interruption for 12 months or longer, the United States would lose the elimination status it has held since 2000, and measles would be reclassified as endemic — continuous domestic circulation, not mainly imported cases.

What would not change matters as much as what would. There are no sanctions or penalties attached to the classification. Vaccine recommendations and medical care do not change: two doses of MMR vaccine are about 97% effective, and one dose about 93% effective. Other countries may update their travel advisories for visitors to the United States — Canada lost its own elimination status in November 2025, which also cost the Americas its regional measles-free designation, and triggered updated CDC travel guidance for Americans travelling to Canada. Regaining the status would need at least 12 consecutive months without endemic transmission, backed by vaccination, surveillance and outbreak-response data.

What this page is, and when it goes out of date

The section below is the dated 2026 picture, merged from the retired measles-2026 page on 7 November 2026. It was published 7 November 2026 — three days before the PAHO commission meets. Its case count is the CDC’s weekly figure as of 5 November 2026, and its answers about elimination status are conditional on a ruling that has not yet happened. The ruling, due from the 10–13 November 2026 meeting, will resolve those conditional answers, and the CDC count will move again with the next weekly update. This page carries no live case count: for the newest figures, the CDC page linked in Sources is the official source, and the paired guide on pandemics happening now carries the wider snapshot.

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