Measles Outbreak 2026: PAHO Data Show Americas Cases Tripled

In 2024, countries across the Americas reported 466 confirmed measles cases. In 2025 they reported 14,891, with 29 deaths across 13 countries. That is a 32-fold rise in one year, and the Pan American Health Organization published it as such.¹

Then 2026 made that number look small. By 18 July, the region had recorded 47,459 confirmed cases and 44 deaths.² The year was barely half over and it had already more than tripled the whole of 2025.

What happened in 2025

The Pan American Health Organization is the World Health Organization's regional office for the Americas. It tracks measles across the region and publishes the counts.

Its February 2026 alert set out the 2025 result. There were 14,891 confirmed cases and 29 deaths across 13 countries, against 466 cases in 2024.¹

Three countries produced almost all of it. Mexico reported 6,428 cases and 24 deaths. Canada reported 5,436 cases and 2 deaths. The United States reported 2,242 cases and 3 deaths.¹

The institutional consequence landed in November 2025. The Pan American Health Organization withdrew Canada's measles elimination status after the virus circulated there for more than twelve months.³ Canada had held that status since the late 1990s.

Because Canada lost it, the region lost it. The Americas had been the only World Health Organization region ever to eliminate measles, and it had done so twice.³ The Public Health Agency of Canada confirmed the loss the same day, dating sustained transmission to October 2024.⁴

Canada can get the status back once transmission of the current strain stops for at least twelve months.⁴

2026 tripled it, and the map changed

By epidemiological week 28, ending 18 July 2026, the region had confirmed 47,459 cases and 44 deaths.² The Pan American Health Organization called it the highest count in the Americas since 2004.²

The countries driving it are different ones. Guatemala reported 30,371 cases and 26 deaths. Mexico reported 12,255 cases and 17 deaths. The United States reported 2,260 and Peru 1,277.² Those four accounted for 95% of regional cases.²

Guatemala had reported one case in all of 2025.¹

The United States tracks its own figures separately. The US Centers for Disease Control and Prevention counted 2,289 confirmed cases in 2025 and 3,294 by 10 September 2026.⁵ That is a larger US figure than the regional report shows, because the regional count stopped in July and the American one runs to September. The two are consistent, not contradictory.

The US outbreak structure is worth noting on its own. In 2026, 95% of US cases were linked to an outbreak rather than isolated, across 38 separate outbreaks.⁵ In 2024 there had been 16 outbreaks.⁵

The gap is the second dose

Coverage headlines usually quote one number. The measles vaccine needs two.

Globally, about 84% of children received a first dose of a measles-containing vaccine in 2025, and 77% received the second.⁶ That leaves nearly 21 million children who missed the first dose, up from 19 million in 2019.⁶

The second-dose shortfall is separate and additional. The Measles and Rubella Partnership counts 20.8 million children who missed the first dose in 2025.⁷ A further 8.3 million got the first dose but not the second. That is roughly 29 million under-protected children in total.

Regional figures show the same shape. In the Americas in 2024, first-dose coverage ran at 89% and second-dose coverage at 79%.¹ Both had risen from 2023, when they stood at 87% and 76%.¹ Coverage is recovering and outbreaks are still growing.

The threshold matters here. Preventing measles outbreaks takes 95% coverage with two doses, a figure the Pan American Health Organization, the World Health Organization and the Measles and Rubella Partnership all use.²⁶⁷

Almost nowhere hits it. Across the Americas, 33% of countries reached 95% first-dose coverage and 20% reached it for the second dose.¹

That difference between 89% and 79% is the mechanism. The children involved are not vaccine refusers who never showed up. They came once and did not come back.

The case data supports that reading. Among 2026 cases in the Americas where vaccination status was known, 78% were unvaccinated and 11% had unknown status.¹

What the headline numbers leave out

The counts are provisional and they move upward. The Pan American Health Organization published the 2025 regional total three times. In November 2025 it reported 12,596 cases across ten countries.³ In February 2026 it reported 14,891 across thirteen.¹ In August 2026 it reported 15,011.² Nothing disagreed. Late confirmations arrived, which is how surveillance works.

A fold-increase depends on its baseline. The 32-fold rise is real, and it is measured from 466 cases in 2024.¹ A small base makes a large multiple. The absolute numbers carry more information.

Deaths are falling even as cases rise. Worldwide, measles killed about 95,000 people in 2024, down 88% from 2000.⁸ Vaccination has saved nearly 59 million lives since 2000.⁸ Cases still reached about 11 million in 2024, nearly 800,000 above the 2019 level.⁸

This is not only an Americas problem. In 2024, 59 countries reported large or disruptive measles outbreaks, close to triple the 2021 figure.⁸ Cases rose 86% in the Eastern Mediterranean region and 47% in Europe against 2019, while Africa recorded a 40% decline.⁸

Who gets hit is not random. The Pan American Health Organization reports the highest incidence in infants under one year, who are too young for the routine first dose, followed by children aged one to four.¹ It names Indigenous communities, migrants and displaced populations as groups at elevated risk.²

Long-run progress is real. The share of children worldwide fully protected against measles rose from 17% in 2000 to 77% in 2025.⁷ The current surge is a reversal from a much higher base than the year 2000.

Does the testing inflate the count?

A recurring objection to outbreak numbers is that the tests manufacture them: run a sensitive laboratory assay often enough and it will produce false positives, and the false positives become the case count. The argument was made about COVID-19 testing and it has been carried across to measles. It does not transfer, for four reasons.

The routine confirmatory test is not PCR. Detecting measles IgM antibodies in a serum sample, collected within the first few days of rash onset, is the routine test used to confirm a case.⁹ That is a blood test. Polymerase chain reaction testing is the supplement, not the foundation. The US Centers for Disease Control and Prevention asks clinicians to collect both a blood specimen and a throat or nasopharyngeal swab from every patient with clinical features compatible with measles.⁹ A case built on two specimen types is not a case built on a nasal swab.

Measles PCR is not a general respiratory test. It amplifies specific regions of the measles genome. That specificity is what makes genotyping possible: a 450-nucleotide window of the nucleoprotein gene, the N-450 sequence, is precise enough that two cases with matching sequences can be connected even when no epidemiological link is visible.¹⁰ Only four wild-type genotypes are in circulation worldwide.¹⁰ A swab taken from the nose is not thereby a test for whatever happens to be in the nose.

Nobody is screening the asymptomatic. The COVID-19 version of this argument depended on mass testing of people with no symptoms, where a small error rate applied to millions of low-risk tests yields a large absolute number of false positives. Measles testing is ordered for people who already have fever and a rash.⁹ Testing a group that is already likely to have the disease is what makes a positive result informative.

False positives do occur, and they get caught. The clearest documented episode in recent years runs opposite to the objection. In American Samoa in 2023, two vaccinated children tested positive for measles IgM and a public health emergency was declared. Eighty-six people were placed under investigation. PCR testing then found measles RNA in one of 62 nasopharyngeal specimens, and that one was vaccine strain virus in a recently vaccinated child. Parvovirus B19, which cross-reacts with measles antibody tests, appeared in 53% of specimens. All 86 were reclassified as non-measles.¹¹ The false positives were on the antibody test, PCR is what corrected them, and the count went down.

Four checks inside the figures already quoted here point the same way.

Deaths move with cases. The region reported 29 measles deaths in 2025 and 44 by July 2026, against 466 total cases in 2024.¹² Deaths are not a laboratory artefact.

The laboratory regime did not change while the numbers did. The same laboratories and the same assays produced 466 confirmed cases in 2024 and 47,459 by the middle of 2026.¹² A constant error rate cannot generate a hundredfold change.

The cases sit with the unvaccinated. Among 2026 cases where vaccination status was known, 78% had never been vaccinated.¹ Random false positives would fall across vaccinated and unvaccinated people roughly in proportion to coverage, which across the Americas is 89% for the first dose.¹

The virus was sequenced. Canada lost its elimination status because laboratory data showed the same measles strain circulating for more than twelve months.³ A false positive yields no genome to sequence and no lineage to follow from one month to the next.

The honest caveat about confirmation is a different one, and it points the same way as the rest of this article. In a large outbreak, a share of cases are confirmed by epidemiological link to a laboratory-confirmed case rather than by a test of their own. That is a reason to treat any single count as approximate. It is not a reason to treat the trend as invented.

Outside the Americas

The regional loss of elimination status is the sharpest story, but measles is rising across most of the world.

In 2024, 59 countries reported large or disruptive measles outbreaks. That is close to triple the number reported in 2021.⁸

The increases are uneven. Against 2019 levels, cases rose 86% in the World Health Organization's Eastern Mediterranean region, 47% in Europe and 42% in South-East Asia.⁸ Africa went the other way, recording a 40% decline.⁸

Vaccination coverage varies just as widely. Rubella vaccine coverage, given in the same combined shot in most countries, reached 96% in South-East Asia and 41% across the African region.⁷

The practical point for a traveller is that regional averages hide a lot. A country inside a low-incidence region can still be running an outbreak, and a country inside a high-incidence region may have strong local coverage.

What this means if you are travelling

The US Centers for Disease Control and Prevention has a standing travel notice on measles. It advises that all international travellers be fully vaccinated with the measles, mumps and rubella vaccine.¹²

The schedule has two parts. Anyone aged 12 months or older needs two doses, given at least 28 days apart.¹² Infants aged 6 to 11 months travelling internationally should get one dose at least two weeks before departure.¹²

That early infant dose does not count toward the routine schedule. A baby vaccinated before their first birthday still needs the standard doses afterwards.¹²

Effectiveness is high but not total. One dose gives about 95% protection against measles and two doses give about 97%.¹²

The notice also covers what to do afterwards. Watch for a rash, high fever, cough, runny nose or red watery eyes. Anyone who develops these during a trip or within three weeks of returning should seek medical care.¹² Tell the clinic before arriving rather than at reception.

How to use these numbers

Check your own second dose before you check a destination's coverage rate. The 78% of cases that were unvaccinated is the actionable statistic here.¹ A destination's national coverage average tells you much less about your personal risk than your own record does.

Do not read last year's outbreak map as this year's. In 2025 the story was Canada and Mexico. In 2026 it is Guatemala, which reported one case the year before.¹² Outbreak locations turn over faster than travel advice does.

Treat a case count as a floor. Every regional total quoted here was revised upward after first publication.¹²³ Recent figures are the least complete ones.

Watch the second-dose figure, not the first. First-dose coverage across the Americas is 89% and climbing.¹ It is the ten-point drop to the second dose that keeps the reservoir stocked, and that is the number that would have to move for elimination to come back.

Footnotes

1. https://www.paho.org/en/news/4-2-2026-paho-issues-epidemiological-alert-amid-continued-measles-transmission-americas-and — Pan American Health Organization, "PAHO issues epidemiological alert amid continued measles transmission in the Americas and urges strengthened vaccination and surveillance" (published Feb 4, 2026). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴

2. https://www.paho.org/en/news/8-8-2026-paho-urges-countries-strengthen-vaccination-and-surveillance-amid-rising-measles — Pan American Health Organization, "PAHO urges countries to strengthen vaccination and surveillance amid rising measles cases in the Americas" (published Aug 8, 2026). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶

3. https://www.paho.org/en/news/10-11-2025-paho-calls-regional-action-americas-lose-measles-elimination-status — Pan American Health Organization, "PAHO calls for regional action as the Americas lose measles elimination status" (published Nov 10, 2025). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴ ↩⁵

4. https://www.canada.ca/en/public-health/news/2025/11/statement-from-the-public-health-agency-of-canada-on-canadas-measles-elimination-status.html — Public Health Agency of Canada, "Statement from the Public Health Agency of Canada on Canada's Measles Elimination Status" (published Nov 10, 2025). Accessed Sep 17, 2026. ↩ ↩²

5. https://www.cdc.gov/measles/data-research/index.html — US Centers for Disease Control and Prevention, "Measles Cases and Outbreaks" (last updated Sep 11, 2026). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴ ↩⁵

6. https://www.who.int/news-room/fact-sheets/detail/immunization-coverage — World Health Organization, "Immunization coverage" fact sheet (last updated Jul 15, 2026). Accessed Sep 17, 2026. ↩ ↩² ↩³

7. https://measlesrubellapartnership.org/mrp-wuenic-data-release-statement-july-2026/ — Measles and Rubella Partnership (American Red Cross, Gates Foundation, Gavi, United Nations Foundation, US Centers for Disease Control and Prevention, UNICEF and the World Health Organization), "WUENIC data release statement" (published Jul 2026). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴

8. https://www.who.int/news/item/28-11-2025-measles-deaths-down-88--since-2000--but-cases-surge — World Health Organization, "Measles deaths down 88% since 2000, but cases surge" (published Nov 28, 2025). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

9. https://www.cdc.gov/measles/php/laboratories/index.html — US Centers for Disease Control and Prevention, "Laboratory Testing for Measles." Accessed Sep 19, 2026. ↩ ↩² ↩³

10. https://www.cdc.gov/measles/php/laboratories/genetic-analysis.html — US Centers for Disease Control and Prevention, "Genetic Analysis of Measles Viruses." Accessed Sep 19, 2026. ↩ ↩²

11. https://pmc.ncbi.nlm.nih.gov/articles/PMC11576048/ — US Centers for Disease Control and Prevention, "Pediatric Rash Illness Outbreak with Initial Positive Measles Immunoglobulin M Antibody Test Results — American Samoa, March–July 2023," Morbidity and Mortality Weekly Report, vol. 73, no. 45 (published Nov 14, 2024). Accessed Sep 19, 2026. ↩

12. https://wwwnc.cdc.gov/travel/notices/level1/measles-globe — US Centers for Disease Control and Prevention, Travelers' Health, "Measles in Globe, Level 1: Practice Usual Precautions" (last updated May 28, 2025). Accessed Sep 17, 2026. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

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