Largest US Measles Outbreak in Years Officially Ends

South Carolina's measles outbreak, the largest in the United States in decades, has officially ended after nearly 1,000 confirmed cases, at least 21 hospitalizations, and a $2 million response cost over six months starting in October. More than 90% of cases occurred among unvaccinated individuals, prompting tens of thousands of MMR vaccine doses to be administered statewide. The outbreak's conclusion comes as the United States faces a broader measles crisis, with 1,792 cases reported in 2026 and at least 22 new outbreaks nationwide, threatening the country's elimination status achieved in 2000. HHS Secretary Robert F. Kennedy Jr. faces congressional criticism for contributing to vaccine hesitancy, while MMR coverage among 3-year-olds has risen above 95% for the first time in over a decade.

South Carolina measles outbreak conclusion and response efforts

• ▪The measles outbreak in South Carolina has ended, with no new cases reported in more than 42 days as of the state health department's Monday announcement
• ▪The South Carolina measles outbreak response cost the state about $2 million
• ▪MMR vaccine doses administered statewide in South Carolina increased 31% year-over-year during the outbreak
• ▪The South Carolina measles outbreak resulted in at least 21 hospitalizations
• ▪The South Carolina measles outbreak resulted in nearly 1,000 confirmed cases over about six months
• ▪South Carolina reported an additional measles case in the month following the outbreak's official end that exposed more than 40 people
• ▪More than 90% of measles cases in South Carolina were among people who had not received the measles-mumps-rubella vaccine

Rising vaccination rates amid outbreak concerns

• ▪The CDC National Immunization Surveys sample size averages about 16,000 people each year
• ▪One dose of the MMR vaccine prevents measles disease about 93% of the time
• ▪MMR coverage among 3-year-olds in the United States ticked above 95% for the first time in more than a decade in 2025
• ▪Two doses of the MMR vaccine raise protection against measles to 97%
• ▪The CDC officially abandoned universal hepatitis B vaccination for newborns in 2025
• ▪About 97% of 3-year-olds in the United States in 2025 had at least one dose of MMR vaccine, according to CDC National Immunization Surveys data

Ongoing measles threat and future public health challenges

• ▪Dozens of measles cases are being added each week in the United States in 2026
• ▪Measles was declared eliminated in the United States in 2000
• ▪At least 22 new measles outbreaks have occurred in the United States in 2026
• ▪The United States is on track to record more measles cases in 2026 than in 2025, which would make it the worst year since measles was declared eliminated in the United States in 2000
• ▪1,792 measles cases have been reported in the United States in 2026 as of the latest CDC data