The flu bug is spreading through Sonoma County, with the peak of the seasonal illness likely to come in the next few weeks, local physicians said.

"It's getting worse," said Dr. Gary Green, chief of infectious diseases at Kaiser Permanente Medical Center in Santa Rosa, reporting an uptick in flu cases in the emergency room, hospital and medical offices.

Santa Rosa Community Health Centers are seeing about 270 flu cases a week, accounting for 7 percent of all patient visits, said Dr. Francisco Trilla, chief medical officer for the clinics.

Green said it is a "typical flu year," with patients experiencing "moderate to severe symptoms," typically coughing, fever and aches.

The Type A influenza this year is a "tough virus," he said, a strain that is laying people low for five to seven days.

The California Department of Public Health's latest flu report, issued Friday, classified the state's influenza outbreak as "moderately severe."

The proportion of people seeing a health care provider for influenza-like illness hit 6.2 percent statewide for the week ending Jan. 26, up from 4.7 percent the previous week, the report said.

Five influenza-related deaths among people less than 65 years old were reported during the week, bringing to 14 the total deaths in California for the 2012-13 flu season.

Two of the deaths were in the San Francisco Bay area. A Public Health Department spokesman said that patient confidentiality laws precluded a more specific location.

California's most recent flu activity is "above the expected level for this time of year," spokesman Corey Egel said.

The state has distributed about 18 million doses of flu vaccine since August and received no reports of widespread flu vaccine shortages, he said.

Dr. Karen Holbrook, Sonoma County deputy health officer, said there has been "no overall shortage" of vaccine in the county.

People intending to get inoculated should call ahead because some providers have experienced temporary shortages, she said.

Kaiser's Santa Rosa facility has vaccinated about 61,000 patients, Green said.

Health officials continue to recommend flu vaccinations, along with hand-washing and covering the nose and mouth when coughing or sneezing.

The vaccine is reportedly effective for 62 percent of the people getting shots, which Trilla said was "a relatively bad ratio."

Green said the effective rate should be higher, but also noted that a vaccinated person — like himself — may get a milder case of the flu.

Green said he fell ill Monday night, stayed home Tuesday resting and drinking fluids, and returned to work on Wednesday.

Flu activity is stable or declining in most of the nation, but increasing in the west, the U.S. Centers for Disease Control and Prevention said in a report for the week ending Jan. 26.

Trilla and Green said the outbreak is still rising in California, and may peak in the next week or two.

Proctor Terrace Elementary School in Santa Rosa has been sending home "a fairly high number" of students with a fever, typical for this time of year, Principal Steve Mayer said.

The school's attendance rate in January was 94.7 percent, down 1.6 percent from the same month of 2012.

Dropping below 95 percent is "abnormal" for the school, but Mayer said he could not attribute it to the flu.

Told that experts predict the flu outbreak will peak in a few weeks, he said "it means we're almost over the hump."

(You can reach Staff Writer Guy Kovner at 521-5457 or guy.kovner@pressdemocrat.com.)