Health officials at University of Michigan Hospital in Ann Arbor say they’re dealing with a severe outbreak of the flu.

A minimum of six people were in the intensive care unit on Thursday, as doctors dealt with what was believed to be multiple cases of H1N1, also know as "Swine Flu."

According to Dr. Lena Napolitano, director of the University of Michigan’s Surgical Critical Care and Intensive Care units, several patients - mostly young or middle-aged - are not doing well.

And, she says, many of the patients are in kidney failure and on continuous bedside dialysis.

Napolitano says the outbreak reminds her of a similar outbreak of the H1N1 virus in 2009.

Health officials say vaccination of high risk persons is especially important to decrease their risk of severe flu illness.

People at high risk of serious flu complications include young children, pregnant women, people with chronic health conditions like asthma, diabetes or heart and lung disease and people 65 years and older.

Vaccination also is important for health care workers, and other people who live with or care for high risk people to keep from spreading flu to high risk people.