This story has been updated with the latest CDC data on the outbreak as of October 25, 2024.

Things appear to be going from bad to worse for McDonald’s, after the fast-food chain became the center of a full-on E. coli outbreak linked to its Quarter Pounders. 

So far, one person has died and 22 have been hospitalized after 75 cases of E. coli were reported from customers who ate at McDonald’s restaurants in 13 states across the U.S., according to the Centers for Disease Control and Prevention (CDC).

While it’s not yet clear which specific food ingredient is contaminated, McDonald’s has stopped using fresh slivered onions and quarter-pound beef patties in several states while the investigation is ongoing, in order to identify what’s causing the illnesses, per the CDC. (Diced onions and other types of beef patties used at McDonald’s have not been implicated in this outbreak.)

Quarter Pounder hamburgers will not be available temporarily in some states while McDonald’s makes some supply changes.

Which states have been affected by the McDonald’s E. coli outbreak?

As of Friday, the CDC said there were 13 states where people have become sick:

Oregon, Kansas, Utah, Wyoming, Iowa, Missouri, Michigan, New Mexico, Washington, and Wisconsin, with most illnesses in Colorado, Nebraska, and Montana.

Here’s a map that shows where the 75 people affected by the outbreak were located along with which states have temporarily stopped selling Quarter Pounder hamburgers either in portions of the state or state wide.

Timeline of when people got sick

This chart from the CDC shows when the people in this E. coli outbreak got sick, with the highest number of people falling ill on October 7. The CDC found that the illnesses started on September 27, and documented them through October 11.

One tricky thing about E. coli is that recent illnesses may not yet be reported because it usually takes 3 to 4 weeks to determine if a person is ill as part of an outbreak.

The actual number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is partly because many people recover without medical care and are not tested for E. coli.

What should I do if I ate at McDonald’s?

The Food and Drug Administration (FDA) recommends that consumers who have already eaten at McDonald’s and have symptoms of E. coli infection should immediately contact their healthcare provider to report their symptoms and receive care.

What are the symptoms of E. coli?

Symptoms depend on the kind of E. coli causing the infection. Most people with E. coli have diarrhea that can be bloody or watery, or stomach cramps that can be severe. Some people also have vomiting or a low fever.

The CDC recommends you call your doctor if you have these symptoms:

• Diarrhea or vomiting lasting more than 2 days
• Bloody poop or pee
• A fever higher than 102 degrees Fahrenheit
• Signs of dehydration
• Signs of hemolytic uremic syndrome, which can lead to kidney failure or death