It's been a relatively mild flu season this year in Hawai'i, as it's been for the past two years, according to state health officials.

A third of the suspected flu cases reported through Feb. 14 that were sent to the state's labs tested positive for flu. While that's not a complete picture of all influenza cases in Hawai'i during this period, it's the best that state health officials can come up with since many cases of flu go unreported.

The traditional 33-week influenza season runs from Oct. 1 to May 20. Data last year showed that 22 percent of suspected flu cases reported were actually the flu, said Dr. Meera Sreenivasan, state Department of Health epidemiologist.

Flu season is actually year-round in Hawai'i because the state gets so many travelers from the southern and northern hemispheres, Sreenivasan said.

The most severe year in recent memory for flu nationwide was in 2003-04, she said.

"We are, overall, having a mild flu season here and on the Mainland," Sreenivasan said. "But it's still not too late to get vaccinated."

While communitywide free flu shots sessions are not available anymore, residents interested in getting one can see their doctor, Sreenivasan said.

Last year the Hawaii Medical Service Association issued 38,245 shots free to members throughout the state from October to mid-December, said Chuck Marshall, HMSA public information coordinator. HMSA offered flu shots free to its members at drugstores and at community events early in the flu season.

That number doesn't include those who paid for a flu shot or got one from a physician, Marshall said.

Fifty-nine percent of the patient specimens that tested positive for influenza so far this season were from schoolchildren and young adults, ages 5 to 24. Typically the disease is a greater threat to the elderly and infirm, Sreenivasan said.

More comprehensive flu data is not available for Hawai'i because many people who have flu symptoms never see a doctor, and because not all doctors volunteer to participate in the state's flu surveillance program.

Nationally, between 5 percent and 20 percent of the population gets the flu each year, more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from flu, according to the Centers for Disease Control and Prevention.

The flu virus is spread mainly from person to person through coughing or sneezing. Touching something with flu viruses on it and then touching your mouth or nose is another way to get sick. Symptoms include fever, headache, tiredness, dry cough, sore throat, runny or stuffy nose and muscle aches.

During the 2007-08 flu season, influenza activity in the United States peaked in mid-February, according to the Centers for Disease Control and Prevention.