Measles Outbreak 2025-2026

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Measles Cases in Delaware

Outbreak History

  • On Monday, July 20, 2026 the Delaware Division of Public Health (DPH) confirmed a positive case of measles in an unvaccinated Kent County man.
  • A second case in Kent County was confirmed the next day, Tuesday, July 21.
  • By Wednesday, July 22, a measles outbreak (3+ cases connected by time and location) was declared in the State when two additional cases were confirmed in Kent County.

Should You Get Vaccinated?

If you were born before 1957, you have likely had the measles, and therefore are considered immune. The measles vaccine was added to the approved vaccine schedule in the 1960s; at that time, only one dose was recommeded. From 1963-1967, a less effective version of the vaccine was given to children. In the 1990s, the recommeded vaccine schedule was updated to include two doses of the measles vaccine. 

You may want to get a booster dose if:

  • If you were born between 1963-1967 (you may have received a slightly less effective vaccine);
  • If you are at a high risk of exposure (i.e., you work in schools, health care clinics, or travel internationally to areas where measels is common) and you only received one dose as a child.

Talk to your doctor about your risk and history. There is a blood test available if you’re not sure of your vaccination status, and vaccines may be available at pharmacies and primary care offices. 

  • Call your preferred facility to ensure they have the MMR vaccine and are available to administer it. 
  • You may be able to receive a MMR vaccine at a Public Health Clinic (view the list here).

If any health care providers identify potential cases, please contact the DPH Office of Infectious Disease Epidemiology (OIDE) during regular business hours (302-744-4990) or Delaware’s 24-hour reporting line outside of normal business hours (1-888-295-5156) to coordinate testing, receive guidance, and limit any further exposures. 

What is Measles?

Measles (rubeola) is more than “just a rash,” it’s a highly contagious viral illness that can cause severe health complications. Measles spreads when someone infected speaks, coughs, sneezes, or breathes, and can linger in the air up to 2 hours after the infected person has left.

Signs and symptoms of measles include: 

  • High Fever
  • Cough
  • Runny Nose
  • Red, Watery Eyes
  • Small white bumps on the inside of the mouth
  • Measles rash: flat red spots, sometimes with small raised bumps on top. The rash typically starts on the face and spreads downward, across the arms, trunk, legs, and feet

Measles can lead to serious complications, including pneumonia, encephalitis (brain swelling), blindness, hearing loss, and even death. This is especially concerning for young children, pregnant women, and people with weakened immune systems.

The measles-mumps-rubella (MMR) vaccine is effective. Two doses provide 97% protection against measles.

Unvaccinated people are at high risk. Roughly 90% of those unvaccinated and exposed to measles will contract the disease.

    Measles Cases Across US

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

    In 2026, there have been 2,566 confirmed measles cases reported by 47 jurisdictions (this total is now more than the total for 2025 (n=2,289)). 

    • Arizona (344 cases, 6 counties, 25 hospitalizations) – transmission slowing
    • California (57 cases, 12 counties) 
    • Delaware (22 cases, 1 county)
    • Florida (155 cases, 16 counties) – as of 8/8/2026
    • North Dakota (38 cases, 5 hospitalizations, 6 counties) – last case 5/14
    • Oregon (45 cases, 2 hospitalizations, 2 counties) – last case 7/12
    • Pennsylvania (296 cases, 52 hospitalizations, 19 counties) – active transmission
    • Texas (190 cases, 12 counties) 
    • Utah (715 cases, 57 hospitalizations, 13 counties) – transmission slowing
    • Virginia (177 cases, 9 hospitalizations, 12 counties) – last case 7/4
    • Washington (55 cases, 4 hospitalizations, 8 counties) 

    In 2025, a total of 2,289 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.

    Other Outbreaks

    • Canada (1,116 cases, 8 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 (11,184 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.
    • 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.