Frozen supplemental shakes have been linked to a nationwide Listeria outbreak that have led to 38 illnesses and 12 deaths.

The supplement shakes were sold to hospitals and long-term care facilities, including nursing homes. There is a nationwide recall for the ReadyCare and Sysco Imperial Frozen Supplemental Shakes. Twelve deaths associated with the listeria outbreak have been linked to the shakes.

Twelve deaths have been reported as part of an outbreak of Listeria monocytogenes infections linked to frozen supplemental shakes, the US Food and Drug Administration said Monday. At least 38 people in 21 states had been infected,

The frozen shakes were served at hospitals and long-term care facilities, sickening 38 people and resulting in 11 deaths in 21 states, according to the FDA.

“Listeria is especially harmful to pregnant women, people 65 or older, and people with weakened immune systems,” the CDC wrote on its website. “This is because Listeria is more likely to spread beyond their gut to other parts of their body, resulting in a severe condition known as invasive listeriosis.”

A listeria outbreak linked to frozen nutritional milkshakes is to blame for 12 deaths and dozens of hospitalizations, the U.S. Food and Drug Administration confirmed Monday following an investigation that spanned years.

Frozen shakes distributed in long-term facilities around the United States have been recalled due to potential listeria contamination. Lyons Magnus announced Feb. 22 that it had issued a recall for 4 oz. Lyons ReadyCare and Sysco Imperial Frozen Supplemental Shakes, which were manufactured by Prairie Farms Dairy, Inc.

Supplemental shakes have been linked to a deadly listeria outbreak. They were distributed in hospitals and long-term care facilities.

In the outbreak, 38 people were infected across 21 states, including Pennsylvania, the FDA said. Most of them lived in long-term care facilities or were hospitalized prior to getting sick.

The supplemental shakes are labeled under the brands Lyons ReadyCare and Sysco Imperial and were sold to institutional customers, including hospitals and long-term care facilities, officials said.