Understanding Current U.S. Measles Outbreaks and Elimination Status

January 21, 2026 | Jessica Baggett, Susan Kansagra, Meredith Allen, Kimberly Martin

In 2016, the Pan American Health Organization (PAHO) declared the elimination of measles in the Region of the Americas, marking a monumental public health achievement. But in 2025, that progress came under threat and remains at risk at the top of 2026 — as recent measles outbreaks have driven the highest case counts in decades, prompting health agencies to reassess elimination status.

Current Outbreaks

Jan. 21 marks one year since the first U.S. measles outbreak of 2025 was reported. The United States went on to experience its worst year for measles in over three decades, with 2,144 confirmed cases. According to CDC, there were 49 outbreaks in 2025 and 88% of confirmed cases (1,884 of 2,144) were outbreak-associated. For comparison, 16 outbreaks were reported during 2024 and 69% of cases (198 of 285) were outbreak-associated. Most 2025 cases occurred in unvaccinated (93%) or under-vaccinated (3%) individuals, and three deaths were confirmed.

Measles Elimination

These outbreaks put the United States at risk of losing elimination status if transmission of the same strain continues for 12 months uninterrupted. In public health terms, “elimination” means that a disease’s continuous (endemic) spread within a region has ceased for at least 12 months. While it doesn’t necessarily mean zero cases, it does mean that local chains of transmission have been interrupted.

The United States achieved elimination status in 2000 due to high coverage with the measles, mumps, and rubella (MMR) vaccine, strong disease surveillance, and public health response to isolated cases. Other countries in the Americas followed similar paths. As a result, PAHO verified the region as measles-free for years.

Why Elimination Status Matters

Elimination is more than a label. It reflects protective immunity within a population and the capacity of the public health system to prevent sustained outbreaks. When elimination status holds:

• Transmission is less likely, preventing widespread illness and death.
• Health care systems avoid unnecessary strain from preventable care utilization.
• Public health systems circumvent the toll of managing large outbreaks.
• Vulnerable groups (i.e., infants too young for vaccination, immunocompromised people) are better protected.
• Public confidence in immunization programs remains strong.

What Happens if Elimination Is Lost?

In November 2025, PAHO announced that the Region of the Americas — including the United States and Canada — lost measles elimination status after endemic transmission persisted, especially in Canada, for more than 12 months. This means that measles is once again circulating continuously within the region rather than only in isolated imported cases and quickly contained outbreaks. CDC is currently working with state and local health officials to analyze data and determine individual U.S. status, assessing if the various outbreaks are linked, which would signify ongoing transmission rather than individual introductions of disease. In November 2025, Canada officially declared their lost elimination status following prolonged transmission in 2024-2025. Ongoing outbreaks in Mexico and other parts of the Americas further contributed to the rise in regional case counts. Finally, PAHO invited both the United States and Mexico to a virtual meeting on April 13 to review their current measles elimination status.

Endemic transmission makes outbreaks larger and more frequent, and increases the number of people who become ill, particularly those not protected by vaccination. Ongoing measles transmission also requires additional public health resources including expanded surveillance, outbreak response, and efforts to raise vaccination coverage, especially in communities with low immunization rates. This adds strain to health departments which often have fixed resources, with one study estimating the average cost per measles case at nearly $60k when including the public health perspective.

Measles transmission in the United States has disproportionately impacted communities with lower vaccination rates. Therefore, the loss of elimination status could necessitate greater attention to vaccination recommendations for international travelers coming to the United States, particularly for infants. For example, similar to U.S. recommendations for those traveling internationally, Australia suggests that infants 6-11 months traveling to areas where measles is endemic or having an outbreak can get assessed for an earlier dose of the measles vaccine.

Response Strategies for Public Health Departments

While the United States works to determine its official status, there are many activities state and territorial public health departments continue to implement to prevent the spread of measles:

Vaccination Campaigns

The MMR vaccine is highly effective in preventing measles, with CDC reporting 93% protection after one dose and 97% after two doses. Herd immunity is a critical preventive measure that interrupts transmission and requires approximately 95% of the population to be vaccinated. Despite this strong science, falling vaccination rates driven by hesitancy, misinformation, and gaps in access have left pockets of the population vulnerable.

Boosting vaccination is the most effective way to stop outbreaks, protect children and adults (particularly those who can’t get vaccinated), and prevent hospitalizations and deaths. Examples of vaccination campaigns include New York’s “Immunization Is Protection” and Minnesota’s reminders about immunization importance.

Analyzing Local Data to Identify High Risk Sub-Populations

Public health departments are evaluating local Immunization Information System data to identify sub-populations with lower measles vaccination rates, areas with high exemption rates, and settings with persistent under-immunization. Examples include Illinois’ Vaccination Coverage Dashboards, Washington’s Immunization Measures by County Dashboard, and American Immunization Registry Association’s Small Area Analysis. Understanding which populations are at higher risk can inform education and outreach activities.

Establishing Relationships with Trusted Community Messengers

Identifying under-vaccinated sub-populations is only beneficial when health departments build trust and authentic engagement within communities. They must work with trusted messengers such as faith leaders, community health workers, and local organizations to co-develop and amplify messages about measles risks and the importance of MMR vaccination. In addition, it is important to tailor communication materials to reflect community languages, values, and concerns. Communities are more likely to accept and act on respectful, relevant messaging.

Examples of successful community partnerships include the Palmetto Community Action Partnership, the Enrichment Services Program, and the Community Action Program for Central Arkansas. Read ASTHO’s “Championing Change” Toolkit for more information and examples.

Supporting Health Care Systems and Providers

Clinicians remain highly trusted voices within communities. Health departments equip providers with up-to-date information and resources to ensure they are prepared to recognize, test, report, and manage measles cases effectively. Examples of these resources include CDC’s Be Ready for Measles Toolkit, Arizona’s Measles Surveillance Toolkit, South Carolina’s Measles Clinical Assessment Guide, and North Carolina’s Measles (Rubeola) Resources for Health Care Providers.