US has 800 measles cases and outbreaks in several states. Here's what you should know

The U.S. has 800 cases of measles nationwide as of Friday, and two more states identified outbreaks this week.

Texas is driving the high numbers, with an outbreak centered in West Texas that started nearly three months ago and is up to 597 cases. Two unvaccinated elementary school-aged children died from measles-related illnesses near the epicenter in Texas, and an adult in New Mexico who was not vaccinated died of a measles-related illness.

Other states with active outbreaks — defined as three or more cases — include Indiana, Kansas, Michigan, Oklahoma, Ohio, Pennsylvania and New Mexico. The U.S. has more than double the number of measles cases it saw in all of 2024.

Measles is caused by a highly contagious virus that's airborne and spreads easily when an infected person breathes, sneezes or coughs. It is preventable through vaccines, and has been considered eliminated from the U.S. since 2000.

Health experts fear the virus will take hold in other U.S. communities with low vaccination rates and that the spread could stretch on for a year.

In North America, an outbreak in Ontario, Canada has sickened 925 from mid-October through April 16. That's on top of cases in Mexico that the World Health Organization has said are linked to the Texas outbreak. A large outbreak in Chihuahua state has 433 cases as of April 18, according to data from the state health ministry.

Here's what else you need to know about measles in the U.S.

How many measles cases are there in Texas and New Mexico?

Texas state health officials said Friday there were 36 new cases of measles since Tuesday, bringing the total to 597 across 25 counties — most of them in West Texas. Four more Texans were hospitalized, for a total of 62 throughout the outbreak, and Parmer and Potter counties logger their first cases.

State health officials estimated about 4% of cases — fewer than 30 — are actively infectious.

Sixty-two percent of Texas' cases are in Gaines County, population 22,892, where the virus started spreading in a close-knit, undervaccinated Mennonite community. The county has logged 371 cases since late January — just over 1% of the county's residents.

The April 3 death in Texas was an 8-year-old child, according to Health Secretary Robert F. Kennedy Jr. Health officials in Texas said the child did not have underlying health conditions and died of ''what the child's doctor described as measles pulmonary failure.'' A unvaccinated child with no underlying conditions died of measles in Texas in late February — Kennedy said age 6.

New Mexico announced five new cases this week, bringing the state's total to 63. Three more people were in the hospital this week, for a total of six since the outbreak started. Most of the state's cases are in Lea County. Two are in Eddy County and Chaves and Doña Ana counties have one each.

State health officials say the cases are linked to Texas' outbreak based on genetic testing. New Mexico reported its first measles-related death in an adult on March 6.

How many cases are there in Kansas?

Kansas has 37 cases in eight counties in the southwest part of the state, health officials announced Wednesday.

Finney, Ford, Grant, Gray and Morton counties have fewer than five cases each. Haskell County has the most with eight cases, Stevens County has seven, Kiowa County has six.

The state's first reported case, identified in Stevens County on March 13, is linked to the Texas and New Mexico outbreaks based on genetic testing, a state health department spokesperson said. But health officials have not determined how the person was exposed.

How many cases are there in Oklahoma?

Cases in Oklahoma remained steady at 12 total cases Friday: nine confirmed and three probable. The first two probable cases were ''associated'' with the West Texas and New Mexico outbreaks, the state health department said.

A state health department spokesperson said measles exposures were confirmed in Oklahoma City and Tulsa, Rogers and Custer counties, but wouldn't say which counties had cases.

How many cases are there in Ohio?

The Ohio Department of Health confirmed 30 measles cases in the state Thursday. The state county includes only Ohio residents.

There are 14 cases in Ashtabula County near Cleveland, 14 in Knox County and one each in Allen and Holmes counties, the state said. The outbreak in Ashtabula County started with an unvaccinated adult who had interacted with someone who had traveled internationally.

Health officials in Knox County, in east-central Ohio, say there are a total of 20 people with measles, but seven of them do not live in Ohio. In 2022, a measles outbreak in central Ohio sickened 85.

How many cases are there in Indiana?

Indiana has confirmed six connected cases of measles in Allen County in the northeast part of the state — four are unvaccinated minors and two are adults whose vaccination status is unknown. The cases have no known link to other outbreaks, the Allen County Department of Health said April 9.

How many cases are there in Pennsylvania?

In far northwest Pennsylvania, Erie County health officials declared a measles outbreak Monday after finding two new cases linked to a measles case confirmed March 30.

The state has had nine cases overall this year, six of which are not linked to the outbreak, including international travel-related cases in Montgomery County and one in Philadelphia.

How many cases are there in Michigan?

Montcalm County, near Grand Rapids in western Michigan, has three linked measles cases. State health officials say the cases are tied to a large measles outbreak in Ontario, Canada.

The state has seven confirmed measles cases as of Thursday, but the remaining four are not part of the Montcalm County outbreak. Michigan's last measles outbreak was in 2019.

Where else is measles showing up in the U.S.?

There have been 800 cases in 2025 as of Friday, according to the U.S. Centers for Disease Control and Prevention, and 10 clusters — defined as three or more related cases.

Measles cases have been reported in Alaska, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Kentucky, Maryland, Minnesota, New Jersey, New York, Rhode Island, Tennessee, Vermont, and Washington.

Cases and outbreaks in the U.S. are frequently traced to someone who caught the disease abroad. In 2019, the U.S. saw 1,274 cases and almost lost its status of having eliminated measles.

What do you need to know about the MMR vaccine?

The best way to avoid measles is to get the measles, mumps and rubella (MMR) vaccine. The first shot is recommended for children between 12 and 15 months old and the second between 4 and 6 years old.

Getting another MMR shot is harmless if there are concerns about waning immunity, the CDC says. People who have documentation of receiving a live measles vaccine in the 1960s don't need to be revaccinated, but people who were immunized before 1968 with an ineffective measles vaccine made from ''killed'' virus should be revaccinated with at least one dose, the agency said.

People who have documentation that they had measles are immune and those born before 1957 generally don't need the shots because most children back then had measles and now have ''presumptive immunity.''

In communities with high vaccination rates — above 95% — diseases like measles have a harder time spreading through communities. This is called ''herd immunity.''

But childhood vaccination rates have declined nationwide since the pandemic and more parents are claiming religious or personal conscience waivers to exempt their kids from required shots. The U.S. saw a rise in measles cases in 2024, including an outbreak in Chicago that sickened more than 60.

What are the symptoms of measles?

Measles first infects the respiratory tract, then spreads throughout the body, causing a high fever, runny nose, cough, red, watery eyes and a rash.

The rash generally appears three to five days after the first symptoms, beginning as flat red spots on the face and then spreading downward to the neck, trunk, arms, legs and feet. When the rash appears, the fever may spike over 104 degrees Fahrenheit, according to the CDC.

Most kids will recover from measles, but infection can lead to dangerous complications such as pneumonia, blindness, brain swelling and death.

How can you treat measles?

There's no specific treatment for measles, so doctors generally try to alleviate symptoms, prevent complications and keep patients comfortable.

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AP Science Writer Laura Ungar contributed to this report.

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This story has been corrected to show that Montgomery and Butler counties in Ohio do not have measles cases in 2025.

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