Local clinics have seen an increase in patients with influenzalike symptoms, likely signaling the onset of flu season.

“This is probably the start of it,” said Dr. Yuan-Po Tu, medical director of walk-in clinics for The Everett Clinic. “We are seeing some in Everett.”

Generally flu season lasts three to four months. It often begins in December, but it’s not unusual for it to begin circulating in January.

Dr. Gary Goldbaum, health officer for the Snohomish Health District, said he, too, has heard of more patients coming to walk-in clinics in Snohomish County with flu’s classic symptoms — fever, cough and sore throat.

“We’re not seeing a major upsurge, but we are getting reports from clinics that they’re seeing more cases,” Goldbaum said.

The types of flu that are circulating this year include H1N2, also known as swine flu, and another type of influenza A. Both of these strains are included in this year’s flu vaccine. So people who have been immunized will probably have good protection against both strains, Tu said.

The Everett Clinic has administered a record-breaking 39,000 doses of flu vaccine, he said. One of the reasons for the high number of people getting immunized may be the uninterrupted supply of vaccine since it first became available in the third week of September, Tu said.

It’s not too late to get the shot, he said. It takes about two weeks for the immunization to become fully effective.

Children younger than 5 have a 50 percent chance of getting the flu if they have not been immunized, he said. And studies have shown that children often pass on the virus to those who live with them.

The Everett Clinic is one of a group of clinics across Washington that monitor flu activity each year, helping state health officials track its spread.

In the past two weeks, the most cases of flu have been reported in the Yakima Valley. “That seems to be the hot spot in Washington state,” Tu said.

Clinics in Olympia and Tacoma are reporting sporadic cases, he said.

Sharon Salyer: 425-339-3486 or salyer@heraldnet.com.