The CDC is advising people to avoid buying or eating romaine lettuce unless they can confirm that it was not grown in the Yuma, Arizona, region, according to a new E. coli outbreak warning issued Friday. The agency is also advising people to throw out any romaine lettuce they may have already purchased. There have been 53 cases so far in the E. coli outbreak, spanning 16 states. No one has died, but 31 people have been hospitalized. Five of those in medical care have “developed a type of kidney failure.” “Traceback investigations show that the lettuce ill people ate came from whole heads of romaine lettuce from the Yuma, Arizona growing region,” the CDC said in a statement.