The United States is having its worst measles year since the early 1990s. By the CDC's weekly counts, 1,636 cases have been reported in 2026 through the week ending September 7, 2026, across 28 states, with two deaths counted nationally and further deaths under review in Pennsylvania. Recent weeks have run between 38 and 155 new cases nationally.
This page is rewritten every week. The prose below explains what is happening and why it matters for a household. The table at the bottom is rebuilt from the CDC's weekly state counts each time the CDC publishes.
Where the cases are
Pennsylvania has reported the most cases of any state this year, followed by South Carolina, Virginia, Ohio and Wisconsin. Florida, Utah, New York, Oregon and Maryland round out the ten states with the most cases. Illinois crossed 20 cases in September, most of them in a two-county outbreak in the center of the state.
Two things about that list matter more than the ranking. First, measles in 2026 is not one outbreak; it is a series of community outbreaks in places with lower vaccination coverage, seeded by travel, each running for weeks to months. Second, a state total tells you little about your county. Pennsylvania's count is concentrated in a few communities; most of the state has none.
How exposure happens
Measles is the most contagious disease we track. An infected person spreads it for about four days before the rash appears, which is before most people know they have it. The virus stays in the air of a room for up to two hours after that person leaves. Nine in ten unprotected people who share that air will get sick.
That is why the exposure notices this year have named specific places and times: an emergency department waiting room, a flight, a church service, a school day. If you were there in that window and are not immune, you were exposed.
Who is protected
Two doses of MMR vaccine are about 97 percent effective and protection lasts for life. One dose is about 93 percent. People born before 1957 are presumed immune from childhood infection. Infants under 12 months are too young for the routine first dose and are the group most at risk in an outbreak, along with pregnant women and people whose immune systems are suppressed.
If you are not sure whether you or your children are fully vaccinated, that is a question for your clinic or your state's immunization registry, and it is worth an answer this year.
What to do if measles is reported near you
- Check that everyone in the household has two documented MMR doses. A child due for the second dose can get it early during an outbreak, and an infant six months or older can get an early first dose if a clinician advises it.
- If you learn you were at a named exposure site and are not immune, call a clinician before going anywhere. There is a short window, 72 hours for the vaccine and six days for immune globulin, in which protection after exposure still works.
- Fever, cough, runny nose and red eyes three to four days before a rash is the pattern. If it appears after a known exposure, call ahead so the clinic can keep you out of the waiting room.
What the weekly numbers can and cannot tell you
The counts below are what state health departments reported to the CDC's National Notifiable Diseases Surveillance System. They are provisional, revised for months, and about three weeks behind the calendar. A state showing zero for the last four weeks with cases earlier in the year most likely had an outbreak that ended. A state climbing week over week is the signal that matters.
Virus Watcher reads these tables, the outbreak reporting, and the local health department notices for the places you name, and Vira texts when something changes there. Join the early access list if you want that for your own city.
Measles this week, by state
Where measles is being reported now. The table is rebuilt every week from the CDC's weekly counts.
CDC week ending September 7, 2026. Counts are provisional and about three weeks behind the calendar. Year to date: 1,636 cases nationally.
| State | This week | Last 4 weeks | 2026 to date |
|---|---|---|---|
| Pennsylvania | 85 | 321 | 604 |
| Wisconsin | 1 | 75 | 111 |
| New York | 12 | 42 | 55 |
| Ohio | 20 | 41 | 116 |
| Maryland | 0 | 21 | 34 |
| Kentucky | 4 | 16 | 33 |
| Florida | 1 | 6 | 84 |
| Oregon | 0 | 6 | 41 |
| Tennessee | 0 | 2 | 4 |
| Virginia | 0 | 1 | 144 |
| Maine | 1 | 1 | 5 |
| Kansas | 1 | 1 | 1 |
| South Carolina | 0 | 0 | 244 |
| Utah | 0 | 0 | 81 |
| California | 0 | 0 | 23 |
States with cases earlier this year and none in the last four weeks: South Carolina, Utah, California, Arizona, Colorado, New Mexico, Minnesota, Texas, Massachusetts, Michigan, Nebraska, New Hampshire.
Recent reports in our feeds:
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Warning over Bangladesh's dengue outbreak after deadliest month (Bangladesh), Oct 1
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Pennsylvania Records a Fifth Measles Death as the Nation Endures Its Worst Year Since 1991 (Pennsylvania), Oct 1
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CDC updates measles toll, now counts 2 deaths, Sep 30
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CDC reports second measles death in US while excluding Pennsylvania deaths (Pennsylvania), Sep 30
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Illinois measles cases hit 23 in 2026, most from Douglas, Moultrie counties outbreak (Illinois), Sep 26
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Trump's FDA nominee says MMR shot is 'safe and effective' at Senate hearing, Sep 25
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Measles outbreak prompts some Pennsylvania doctors to offer early MMR vaccine doses (Pennsylvania), Sep 25
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California warns of measles exposure in six counties from unvaccinated train passenger (California), Sep 20