McDonald’s shares slide in wake of fatal E. coli outbreak. What to know

McDonald's E. coli outbreak has killed one person and at least 10 people have been sent to the hospital, the U.S. Centers for Disease Control said on Tuesday.

Shares of McDonald’s fell nearly 6% in premarket trading on Wednesday after an E. coli outbreak linked to the restaurant chain’s Quarter Pounder hamburgers resulted in the death of one person and sickened 49 people in the U.S.

The outbreak was reported in 10 states and at least 10 people have been sent to the hospital, the U.S. Centers for Disease Control said on Tuesday. Cases started to be reported in late September and continued into October.

“This public health scare is the last thing McDonald’s needs given that it’s already been struggling to drive growth,” said Susannah Streeter, Hargreaves Lansdown’s head of money and markets.

The E. coli O157:H7 strain that led to the McDonald’s outbreak is said to cause serious illness and is the same as a strain linked to a 1993 incident at Jack in the Box, which killed four children.

The outbreak could have been caused by the use of slivered onions used in the Quarter Pounder and was sourced from a single supplier that serves three distribution centers, McDonald’s said based on its initial findings.

In the past, two notable E. coli outbreaks – at Chipotle Mexican Grill  in 2015 and Jack in the Box in 1993 – significantly hurt sales at the companies.

Chipotle took a year-and-a-half to stabilize, while Jack in the Box sales declined for four straight quarters, Raymond James analyst Brian Vaccaro said.

McDonald’s posted a surprise drop in sales worldwide in July, its first quarterly decline in more than three years, as deal-seeking consumers pushed back on its higher priced menu items.