Grab the hand sanitizer: the flu season is here with a vengeance.

Statewide, more than 150 people have been admitted to hospital intensive care units with the flu, and six have died, according to Illinois Department of Public Health.

Locally, hospitals are seeing a high volume of cases. Kelly Barbeau, spokeswoman for St. Elizabeth's Hospital, said there have been more than 300 people through the emergency room alone in the last week.

"We're seeing an extremely high level of patients presenting with flu symptoms, both at our hospital and at our urgent care center," Barbeau said.

Some hospitals, including St. Elizabeth's in Belleville and Anderson Hospital in Maryville, instituted restrictions on visitors to prevent the spread of the virus to patients with compromised immune systems.

Memorial Hospital in Belleville had 145 positive flu tests, with the majority of patients from newborns up to 25 years old. Nearly all have been influenza B, with about 6 percent influenza A. Of the positive cases, 11 people have been admitted to the hospital, with an average age of 57.

In Chicago, eight hospitals had to send ambulances elsewhere as they dealt with an influx of patients with flu-like symptoms. Emergency rooms were at capacity as of Tuesday morning at several Chicago hospitals and in Rockford, and non-critical patients were being re-routed to other hospitals.

U.S. health officials reported that the strain of the influenza virus going around this year has been linked to more hospital admissions and deaths. In contrast, last year's flu season hit later and illnesses were milder.

This flu season is off to its earliest and most active start in nearly a decade, health officials said.

"This season is a reminder of how serious flu can be," said Dr. Julie Morita of the Chicago Department of Public Health.

Statewide, flu-related deaths have been in Cook, Will and Coles counties, and mostly afflicted people in their 50s and older. The federal Centers for Disease Control and Prevention has listed Illinois among 29 states experiencing high flu activity as of last week.

Strains seen this year include influenza A, both H3N2 and H1N1, and influenza B. While influenza B was more prevalent in November and December, Barbeau said, the past two weeks have been evenly matched between influenza A and B.

Doris Driscoll, infection control nurse at Anderson Hospital, said that about 75 percent of the cases they've seen are influenza B, and the remaining 25 percent influenza A.

"I have reported more influenza B this year than I have in all the other years combined," Driscoll said.

Hospital visitors should refrain from visiting a patient if they have a cold or any flu-like symptoms, including fever, sore throat, body or muscle aches, headache, cough or runny nose. Hospitals are also forbidding visits from children younger than 18 and pregnant women.

Healthy visitors should wash hands and use hand sanitzer after arriving and before leaving, as well as before and after entering the patient's room. All people are reminded to cover their mouths when coughing or sneezing and to wash hands thereafter.

At Anderson, visitors at the obstetrics unit are limited to four people as designated by the mother, and no visitors younger than 18 are permitted on patient floors.

"Patients are hospitalized for a reason, so we cannot risk subjecting them to the flu and other cold viruses," said Lisa Klaustermeier, chief nursing officer. "We regret any inconveniences, but the health of our patients is our priority."

And the flu shot is still available -- mandatory for some workers. "This is the second year we have required all employees to have flu vaccinations, to protect our patients and our employees as well," Barbeau said. "We have had some people decline, and they will be required to wear a mask during high flu activity."

Elsewhere in the country, controversy erupted as some health workers have been fired for refusing the flu shot. In Springfield, Mo., a nurse refused the vaccination for religious reasons and was fired when she also refused to wear a mask at work. In Indiana, a hospital fired eight employees for refusing the flu shot.

In most cases, flu sufferers just need to stay home, rest and drink fluids, Driscoll said. Patients should contact their doctors if they have weakened immune systems or lung, liver and kidney disease. Patients should seek immediate medical attention if they have trouble breathing, pain or pressure in the chest or abdomen, sudden dizziness, confusion, severe or persistent vomiting or symptoms that get better and then get worse with fever and/or a rash.

While antiviral drugs may help combat the flu, they must be taken within 24 hours of symptoms appearing, Driscoll said.

Any flu patient should stay home for at least 24 hours after fever has gone without the use of medication. Influenza is contagious as early as 24 hours before feeling ill to 5-7 days after getting sick, Driscoll said.

Symptoms similar to the flu also can indicate respiratory syncytial virus, otherwise known as RSV. Young children are the most likely to come down with RSV, which cannot be treated with antibiotics and in rare cases can be life-threatening. Dr. Matthew Broom, who teaches pediatrics at St. Louis University, recommends frequent hand-washing and keeping small children and infants away from anyone with cold symptoms.

The Associated Press contributed information to this article. Contact reporter Elizabeth Donald at edonald@bnd.com or 239-2501.