Twin Cities medical clinics have a message for flu patients: Unless you're really, really sick, don't come in.

Facing a flu pandemic that could infect as many as a quarter of all Americans this fall, primary care clinics are gearing up for big crowds and a supreme exercise in logistics: how to treat the sick while keeping them from infecting the healthy.

As a result, they're asking people with mild flu symptoms to stay home. Patients who want to talk with a doctor or nurse, they say, should phone in.

"Don't come in unless it's a particularly severe illness, with fever for more than 48 to 72 hours, or wheezing or respiratory problems," said Dr. James Breitenbucher, who oversees H1N1 planning at Fairview Health Services. "For otherwise healthy people, there is little or no value in coming in."

The exceptions are the very young and the very old, as well as people with underlying conditions such as asthma, diabetes or heart disease. For them, the new flu strain can be deadly.

As they prepare for an autumn surge in cases, many clinics are already taking steps to stop the virus from spreading from one patient to another. Some are slapping masks on any feverish, coughing patients who show up and rushing them into exam rooms to minimize contact with others in the waiting room.

Last spring, Allina Hospitals and Clinics reserved side entrances, marked with signs and cones, at several clinics, where patients with flu symptoms were met by masked and gowned health workers. It may do so again this fall.

HealthPartners recently authorized its hot line nurses to prescribe antivirals for those in high-risk groups so patients can go directly to the pharmacy.

Until the H1N1 vaccine arrives, probably early next month, the best line of defense is to prevent the sick from infecting others, health officials say.

Avoiding a spike

Outbreaks like this -- the first global flu pandemic in 40 years -- tend to play out in a bell curve, with the greatest number of cases bunched in the middle. Health officials know they can't stop the spread, but they are working hard to slow it down, flatten the curve, and avoid a sudden, sharp spike that could overload the system.

Or as the Minnesota state epidemiologist, Dr. Ruth Lynfield, puts it, to "decompress the peak burden on health care infrastructure."

Health community on alert

So far, clinics say they are able to handle the number of calls and walk-in patients showing flu-like symptoms. If the number of cases jumps, they have contingency plans.

Park Nicollet, for example, may expand call centers and designate special flu clinics with expanded hours.

All the hospital and clinic groups are poised to delay elective surgeries, if needed, allowing them to deploy more nurses and doctors to handle flu cases.

The Children's Physician Network, a group of about 20 independent pediatric practices, is working with the state to set up a statewide telephone triage service by mid-October, said Dr. Pete Dehnel, medical director for the group.

"Ninety percent of that is just being prepared," Dehnel said.

For Minnesota's hospitals and clinics, the preparation started many months ago.

They stocked up on gloves, masks and antivirals. They fitted health care workers with masks and told sick workers to stay home for seven days or at least 24 hours after their symptoms go away.

Allina, the Twin Cities' biggest hospital and clinic chain, tweaked its personnel policies so workers who didn't have enough sick days banked could stay home anyway and make it up later. "We didn't want people to not be honest about their [health] situation," said Pete Huber, Allina's director of emergency management.

Little fingers

Pediatric offices face a particular challenge. Children are notorious for touching everything. Then putting their fingers in their mouths.

At Central Pediatrics, which has clinics in St. Paul and Woodbury, anybody with a cough or fever is asked to mask up immediately.

"I had 25 patients this morning, and more than half had H1N1," Dr. Shelly Strong, the clinic's managing partner, said Tuesday.

Clinic workers are wiping down chairs with sanitizer more often. The clinic also set aside one exam room for babies' well checks. Sick kids don't go in there.

If the pandemic worsens, the clinic may start segregating patients -- seeing healthy kids in the morning and reserving the afternoons for sick kids. "What we don't want is to mix the sick kids with the well kids," Strong said.

At least there's one less thing to worry about these days. Two years ago, the clinic got rid of its fish tank. Kids used to press their hands and faces against the glass, leaving handprints along with all manner of germs.

Now the clinic just has TV screens with images of swimming fish -- interspersed with health messages.

Chen May Yee • 612-673-7434