Measles Outbreak 2025-2026

The ICD will continue to update this page as the situation evolves. Check back frequently!

Measles

Measles (rubeola) is more than “just a rash,” it’s a highly contagious viral illness that can cause severe health complications, including pneumonia, encephalitis (inflammation of the brain), and death, especially in unvaccinated individuals.

  • The measles-mumps-rubella (MMR) vaccine is effective. Two doses provide 97% protection against measles.
  • Measles is very contagious. It spreads when someone infected speaks, coughs, sneezes, or breathes. It can linger in the air up to 2 hours after the infected person has left.
  • Unvaccinated people are at high risk. Roughly 90% of those unvaccinated and exposed to measles will contract the disease.

Current Outbreak

With the rising outbreaks of measles across the United States, and the first measles-related death in a decade, it’s crucial to stay alert and informed. Understanding measles, its symptoms, and how to stay protected is essential for keeping our communities safe.

Measles Cases Across US

Johns Hopkins has created a Measles Tracker, looking at total measles cases from Jan 1, 2025. Additional Johns Hopkins dashboard. 

In 2026, there have been 1,136 confirmed measles cases reported by 28 jurisdictions. 

In 2025, a total of 2,281 confirmed measles cases were reported by 45 jurisdictions. There were 50 outbreaks (defined as 3 or more related cases) reported, and 90% of confirmed cases were outbreak-associated. A total of 25 measles cases were reported among international visitors.

(cases with a * are likely linked)

Other Outbreaks

  • Canada (254 cases, 7 jurisdictions) – October 26, 2025 marked one full year of continuous measles transmission in Canada, which led to Canada losing its measles elimination status (5,056 cases in 2025)
  • Mexico (740 cases in 2026)

Measles Facts

  • Measles was declared eliminated from the United States in 2000. This means that measles will only spread if started by someone with the virus entering the country and spreading it to un- or under-vaccinated individuals.
  • Measles is the most contagious vaccine-preventable disease. One person can spread measles to 16-18 unvaccinated individuals. In order for measles not to spread, a community (herd) immunity level of at least 95% must be maintained.
  • Your best defense against measles is a measles, mumps, and rubella (MMR) vaccine, with two doses being 97% effective at preventing measles (one dose is 93% effective). The vaccine can also prevent or reduce the severity of infection if administered to an unvaccinated person within 3 days after an exposure. (source: Immunize.Org)
  • The MMR vaccine can keep a child in school if they are exposed but vaccinated.
  • Overall measles coverage in the US was 90.6% in 2021. In Delaware, that number was 89.4% for the same year. These numbers do not account for areas of lower vaccination coverage, like the Mennonite community at the center of the Gaines County, Texas outbreak.
  • Due to COVID-19, vaccination rates of children dropped, and now up to 13.9% of children nation-wide are susceptible to measles.

Health Advisories

CDC Health Alert Network: Expanding Measles Outbreak in the US and Guidance for the Upcoming Travel Season

Delaware Division of Public Health: Recommendations to Protect Yourself and Your Children from Measles

Sharing about Measles / MMR Vaccine

Answers to Common Questions and Concerns

Resources for Providers

If a health care provider, laboratory or hospital suspects, tests, or diagnoses an individual with measles, DPH should be notified immediately.