Overview
- Kane County confirmed a second measles case on Sept. 9 that health officials say was in a vaccinated contact of an unvaccinated patient first identified in late August.
- Austin Public Health reported a second 2026 case in an unvaccinated infant who likely caught measles while traveling internationally and visited two local clinics while infectious.
- Chicago health officials warned that a confirmed case passed through Union Station on Aug. 27 and returned on Aug. 28, and asked travelers from those dates to monitor for symptoms through Sept. 18.
- Local agencies have already traced large contact lists from earlier exposures — Kane County identified roughly 1,600 contacts from its initial case — and are notifying, testing, vaccinating, or asking unvaccinated contacts to quarantine for up to 21 days.
- Health leaders point to larger regional activity, including more than 100 cases in southwestern Wisconsin and five cases in Barren County, Kentucky, and are urging MMR vaccination and symptom monitoring to limit spread and severe illness.