Why US is experiencing largest measles outbreak

Children getting immunised in the ongoing measles, mumps and rubella vaccination in Wajir County.[Jeckonia Otieno, Standard]

The measles outbreak in South Carolina reached 876 cases on Feb. 3, 2026. That number surpasses the 2025 outbreak in Texas and hits the unfortunate milestone of being the largest outbreak in the U.S. since 2000, when the disease was declared eliminated here.

The outbreak is exposing the breadth of dangers the disease can pose. South Carolina’s state epidemiologist revealed on Feb. 4 that cases of brain swelling, a rare complication of the disease, had emerged in some infected children, according to Wired magazine.