The peak of flu season is on schedule to arrive in California in the coming weeks as the rest of the nation is experiencing an early influx of the illness, local health officials said.

Health officials urged those in the Tri-Valley who have not yet been vaccinated to get their flue shots quickly. The vaccinations are available at the ValleyCare Health System's Urgent Care facility at 4000 Dublin Blvd. in Dublin for $25. Some pharmacies also are offering flu shots in that price range, although many have already exhausted their supplies.

Flu activity usually starts in January and peaks in February, but the Centers for Disease Control and Prevention noted flu activity started in some parts of the country as early as December.

Dr. Yvonne Maldonado, chief of pediatric infectious disease at Lucile Packard Children's Hospital at Stanford, said on the West Coast influenza strains are expected to start affecting more people in the coming weeks, peaking in February.

"The upswing came four to six weeks early, but the West Coast seems to be spared," Maldonado said.

She explained multiple strains circulate around world, starting in the east and moving west.

"We know that the flu is going to come every year," Maldonado said.

There are two strains -- A and B -- that make their way through populations during the winter months, however this year there is a new variety of strain A, known as H3N2. Maldonado said doctors are seeing more of this strain than the usual A or B strains.

"This particular year people are getting sicker with this H3N2," she said.

Fortunately, Maldonado said that strain is in the vaccine, however, "not everyone gets vaccinated."

"People should still try to get vaccinated," she said. "It really is the best way to prevent disease."

As flu season starts to pick up, Maldonado noted there are many other viruses floating around, many which have flu-like symptoms, but are not actually influenza.

Already, before the usual peak period, 18 children flu-related deaths have been reported nationwide and 29 states have reported flu hospitalizations.

In the Bay Area, no flu-related deaths have been reported.

The San Mateo County Health System is gearing up for an active flu season, with vaccines available throughout the county.

All residents older than 6-months-old are encouraged to get vaccinated.

Anyone looking for more information about staving off the flu can visit smchealth.org/flu.

Some Bay Area retail pharmacies are offering free vaccines for children ages 4 through 18 until Jan. 31. Information about locations can be found at shootheflu.org.

Sasha Lekach, Bay Area News Service, contributed to this story

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