Allina Health is restricting visitors at its 12 Twin Cities hospitals and its eye institute to protect patients and staff from influenza.

Seasonal flu is now widespread throughout Minnesota, state health officials said in a weekly flu update Thursday, with the number of cases rising sharply for the second consecutive week.

Allina Health is asking people who are sick — and all children under age 5 — to refrain from visiting patients in the hospital. Visitors with a cough or sore throat will be asked to wear masks while in the building. All visitors are asked to wash hands or use antibacterial hand cleanser during their visits.

Compassionate exceptions may be considered based on a patient's condition.

Allina Health locations include Abbott Northwestern Hospital and Phillips Eye Institute in Minneapolis; United Hospital in St. Paul; Buffalo Hospital; Cambridge Medical Center; District One Hospital in Faribault; Mercy Hospital in Coon Rapids; Mercy Hospital-Unity Campus in Fridley; New Ulm Medical Center; Owatonna Hospital; Regina Hospital in Hastings; St. Francis Regional Medical Center in Shakopee, and River Falls Area Hospital in River Falls, Wis.

Children's Hospitals and Clinics of Minnesota has also put winter-visiting infection guidelines in place, asking those with symptoms to wear facemasks, restricting visitors who are ill or under age 5, as well as providing different waiting rooms for those who are ill and those who are not.

People infected with the flu can pass it on to others 24 hours before they develop symptoms. In addition to airborne transmission, the virus can live on surfaces for up to 72 hours.

Glenn Howatt contributed to this report. Shannon Prather • 612-673-4804