Colorado health authorities said an unvaccinated child younger than five who recently returned from Chihuahua, Mexico, has been hospitalized with measles, raising the state’s 2025 total to 17 confirmed infections, five of which have required hospital care. The Colorado Department of Public Health and Environment and the Adams County Health Department warned that anyone who visited the emergency department at Children’s Hospital Colorado in Aurora on Aug. 12 between 6:36 p.m. and 10:16 p.m. could have been exposed. Measles can remain airborne for up to two hours; officials urged unvaccinated contacts to obtain an MMR shot within 72 hours of exposure and for all visitors during the window to monitor for symptoms through Sept. 2. The case comes as measles activity accelerates nationwide. The Centers for Disease Control and Prevention’s latest figures, issued Aug. 6, list 1,356 infections in 32 outbreaks—the highest U.S. tally since elimination was declared in 2000. Idaho on Thursday confirmed its first case in the state’s panhandle since 1991, also involving an unvaccinated child.