The CDC reports that the outbreak has resulted in one fatality and several severe cases, including a child suffering from hemolytic uremic syndrome, a serious kidney condition. The infections, reported between late September and mid-October, have predominantly affected residents of Colorado and Nebraska. Initial investigations suggest that slivered onions served on the burgers might be a likely source of contamination, leading to McDonald's halting the use of these onions and the temporary removal of Quarter Pounders from their menus in affected areas.

In response to the outbreak, McDonald's has cooperated with health officials, halting the distribution of implicated ingredients from a single supplier. The company emphasizes its commitment to food safety and has temporarily removed the Quarter Pounder from its menu in the affected states to prevent further spread of the bacteria. Health officials continue to urge anyone who has consumed the implicated product and is experiencing symptoms to seek medical attention immediately.

This outbreak is particularly concerning due to the severe nature of E. coli O157:H7, which is known to cause significant health issues such as kidney failure and even death. The CDC and other health agencies are working diligently to control this outbreak and prevent future incidents. This situation highlights the critical importance of stringent food safety measures and prompt action in the face of potential foodborne illnesses.