The United States is poised to lose its measles eradication designation in 2026 unless public health experts are able to curb an ongoing outbreak of the infection in South Carolina and several other states. 

South Carolina has been the latest state to struggle with a measles outbreak in 2025, largely due to pockets of unvaccinated communities. But public health experts warn that the disease will no longer be considered eliminated in the United States unless the spread of the virus comes to a halt within a few short weeks.