Measles

Measles is a very contagious rash illness caused by a virus. Common complications from measles include ear infections and diarrhea. Measles can cause severe illness and serious health complications, especially in children younger than age 5 years, adults older than age 20 years, pregnant women, and people with immune system problems. These complications include:

• Pneumonia
• Brain swelling, which could lead to permanent brain damage
• Death
• Subacute sclerosing panencephalitis (SSPE): a very rare progressive, disabling, and deadly brain disorder that results from a measles virus infection acquired earlier in life. SSPE generally develops 7 to 10 years after a person has measles, even though the persons seems to have fully recovered from the illness.

Current Events

Measles in the United States

Measles is a highly contagious viral disease that can cause severe health complications, especially in young children, pregnant women, and individuals with weakened immune systems. While the U.S. achieved near-elimination of measles in the year 2000 through widespread vaccination efforts, recent years have seen an increase in measles cases, primarily due to lapses in vaccination coverage and international travel.

In recent years, there have been cases of measles across the U.S. These cases have been linked to lower vaccination rates in certain communities, as well as travel to regions where measles is still common. According to the Centers for Disease Control and Prevention (CDC), most of the measles cases reported in the U.S. are among unvaccinated individuals.

In 2024, the U.S. reported 285 measles cases across 33 jurisdictions, with 16 outbreaks affecting 69% of cases. The majority of cases were in children under 5 (42%) and unvaccinated or unknown vaccination status (89%). Hospitalizations occurred in 40% of cases, with the highest rates among children under 5 (52%) and adults 20+ (39%). As of December 16, 2025, the U.S. reported 1,958 measles cases, with 93% of cases among unvaccinated or unknown vaccination status individuals. The age distribution was in children under 5 years (26%), between 5-19 years (41%), 20+ years (32%), and age unknown (13 cases, 1%).

In 2025, there were a total of 2,285 measles cases. Among these, 2,260 cases were reported by 45 jurisdictions, with 48 outbreaks affecting 90% of confirmed cases (2,062 of 2,284). A total of 25 cases were reported among international visitors to the U.S. The majority of cases were ages 5-19 years old (44%) and among the unvaccinated or unknown vaccination status (93%), one MMR dose (3%) and two MMR dose (4%). Hospitalizations occurred in 11% of cases (242 of 2284 cases), with the highest rates among children under 5 years old (18%). There were 3 deaths associated with measles: two confirmed cases were both from Texas in school-aged children and who were not vaccinated and had no known underlying conditions, and one case in New Mexico with an unvaccinated individual who did not seek medical care before passing. For more information, visit Texas Health and Human Services and New Mexico Health’s webpage for their respective cases.

There were 48 outbreaks reported in 2025, and 90% of confirmed cases (2,063 of 2,285) were outbreak associated; compared to 16 outbreaks were reported during 2024 and 69% of cases (198 of 285) were outbreak-associated in the United States

Hospitalizations occurred in 11% of cases, with 18% of children under 5 years old hospitalized, 6% in ages between 5-19 years, 11% in 20+ years and older, and 13 cases  were unknown.

As of April 2, 2026, the U.S. reported 1,671 confirmed cases, with 92% of cases with unvaccinated or unknown vaccination status, 4% with one MMR dose, and 4% with two MMR. Of cases, 21% occurred in children under 5 years old, 52% in ages between 5-19 years, 27% in 20+ years and older, and 5 cases were unknown. Among these, 1,661 cases were reported by 33 jurisdictions. A total of 10 measles cases were among international visitors to the U.S.

There have been 17 new outbreaks reported in 2026, and 94% confirmed cases (1,570 of 1, 671) are outbreak-associated (374 from outbreaks starting in 2026 and 1,196 from outbreaks that started in 2025).

U.S. Hospitalizations and Deaths in 2026

You can also visit the CDC’s Newsroom for current events on measles in the United States.

Measles in Hawaiʻi 2025

Kauaʻi

On March 16, DOH was notified of wastewater sample from Kauaʻi County tested positive for measles virus. The DOH continues to monitor measles statewide, including on Kauaʻi. Healthcare providers have been notified and reminded to remain alert for patients who may present symptoms consistent with measles. There are no suspected measles cases identified on Kauaʻi.

On October 20, 2025, DOH was notified of a wastewater sample collected in East Kauaʻi County on September 24, 2025, had measles virus. No cases of measles were reported in Kauaʻi County in 2025.

Oʻahu

On March 7, the Hawaiʻi DOH State Laboratories Division had confirmed a case of measles in a vaccinated adult visitor to Oʻahu. The visitor had recently arrived in the state of Hawaiʻi from a region of the continental U.S. with known measles transmission. After arrival, the visitor became ill, sought medical care, and recovered at a private residence on Oʻahu. DOH issued a medical advisory to healthcare providers statewide with information on how to test for measles and current vaccination recommendations.

In April 22, 2025, two laboratory confirmed cases of measles were identified, one in a school-age child and a second in an adult member of the child’s family. Both individuals had returned from international travel just prior to diagnosis and recovered at home. DOH issued news releases to inform the public of potential exposure to measles at various locations on Oʻahu. DOH had identified 92 individuals who were exposed to one or both cases of measles and had successfully contacted 88 of them. Most of these individuals have either been vaccinated or have other proof of immunity. Those without evidence of immunity have been advised to isolate at home and are being actively monitored. In 2025, Oʻahu was only island in the state of Hawaiʻi with confirmed measles cases.

Maui

DOH was notified of a second detection of measles virus in wastewater from West Maui County. This follows an earlier detection of virus in Maui wastewater from samples collected on November 18, 2025 in Central and West Maui as previously reported, as well as two rounds of negative wastewater samples collected in West Maui on November 24, 2025 and November 25, 2025 from the same treatment plant.

Measles has not been detected again at the Central wastewater treatment site, after three rounds of testing in late November. While no cases of measles have been confirmed on Maui or elsewhere in the state at this time, DOH did issue a medical advisory to healthcare providers statewide with information on how to test for measles and current vaccination recommendations.

Why is this a public health concern in Hawaiʻi?

Measles is highly contagious and can lead to severe complications, such as pneumonia, brain inflammation, and death, especially in young children and those with weakened immune systems. It spreads quickly, even before symptoms appear, and outbreaks can occur in communities with low vaccination rates.

If one person has it, up to 9 out of 10 people nearby will become infected if they are not protected. It spreads through direct contact with an infected person or through the air when an infected person coughs or sneezes. An infected person can spread measles to others from four days before developing the rash through four days afterward. The virus can remain in the air for up to two hours after an infected person has left the room.

While preventable through vaccination, measles remains a serious risk, highlighting the importance of maintaining high vaccination coverage to protect vulnerable populations and prevent widespread outbreaks.