At least 588 measles cases have been confirmed so far this year across the U.S., according to updateddatafrom the Centers for Disease Control and Prevention.
This means the U.S. has seen more cases in about one month than is typically recorded in an entire year.
Only nine other years, including last year, have had higher case counts since measles was declared eliminated in 2000.
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The high case counts in 2026 are largely being driven by a measles outbreak in South Carolina. The total number of cases in the outbreak, which began in October, stands at 847, according to the South Carolina Department of Public Health.
More than 400 people are currently in quarantine across South Carolina, including students from various schools, according to health officials.
Across the U.S., at least 17 states have also reported measles cases this year including Arizona, California, Florida, Georgia, Idaho, Kentucky, Minnesota, Nebraska, North Carolina, Ohio, Oregon, South Carolina, South Dakota, Utah, Virginia, Washington and Wisconsin.
Almost all cases are tied to ongoing outbreaks in pockets of undervaccinated or unvaccinated communities. Just three measles cases were reported among international travelers so far this year, according to CDC data.
Last year, the U.S. saw a record-breaking number of measles cases reported with 2,257 infections, the highest figure recorded since 1992. The U.S. could be on pace to surpass that record if cases continue to mount at this rate.
New map shows how to spot the measles risk level in your ZIP code
The CDC currentlyrecommendsthat people receive two doses of the measles, mumps, rubella (MMR) vaccine, the first at ages 12 to 15 months and the second between 4 and 6 years old. One dose is 93% effective, and two doses are 97% effective against measles, the CDC says.
However, federal data shows vaccination rates have been lagging in recent years. During the 2024-2025 school year,92.5% of kindergartners received the MMR vaccine, according to data. This is lower than the 92.7% seen in the previous school year and the 95.2% seen in the 2019-2020 school year, before the COVID-19 pandemic.
The national trends mirror those see in counties across the U.S. Arecent map from ABC News-- a collaboration with researchers from Boston Children's Hospital, Harvard School of Medicine and Icahn School of Medicine at Mt. Sinai that allows people to type in their ZIP code and see the measles risk in their area -- found a wide range of risks in areas across the U.S.
Some counties and ZIP codes fell into the "lowest risk," with 85% or more of children under 5 years old receiving one or more measles vaccine dose to "very high risk" with fewer than 60% of children under age 5 receiving one or more measles vaccine dose.