Outbreaks of flu are ‘way up’

The swine flu virus is spreading rapidly throughout California and Los Angeles, officials said Thursday.

More than half of local health departments in the state are seeing active outbreaks, Dr. Mark Horton, the state public health officer, said at a news conference Thursday.

More than 5% of patients going to doctor’s offices have flu-like symptoms, which is much higher than the usual 2%, according to an estimate based on about 50 physicians across California who monitor flu activity for the state.

“We are seeing a continued ramp-up of the virus activity,” Horton said. “That is very unusual for this time of year.”

The flu outbreak is consistent with what is seen during a “moderately severe seasonal flu outbreak,” he said.

L.A. County is seeing the highest levels of flu since the H1N1 flu strain was identified in the spring, said Dr. Jonathan Fielding, the county’s health officer.

Until last week, 276 people had been hospitalized for flu this year. But in the last week alone, 91 additional people were hospitalized.

“Outbreaks are definitely way up,” Fielding said. “It’s a very significant situation.”

The H1N1 flu strain is by far the predominant flu strain circulating in California. It accounts for 95% of the flu samples tested by the state.

L.A. County saw a surge in flu cases beginning in September, just as schools resumed classes.

Children and young adults are being hit disproportionately hard by the strain.

Most of those who have died from H1N1 had underlying medical problems, such as asthma or chronic lung disease. Chronic illness reduces the strength of the immune system to combat the flu. Pregnant women are also at risk because the fetus reduces the expectant mother’s lung capacity.

Because the H1N1 strain grows in a patient’s airways, the lungs become inflamed, limiting the body’s ability to absorb oxygen into the bloodstream.

Most people who get the flu can recover in less than two weeks without seeing a doctor or taking antiviral drugs.

Although officials have been urging the public to get seasonal and swine flu shots, the supply of the latter is limited for now.

California has received 750,000 swine flu doses in the last two weeks, a tiny fraction of the 20 million expected to be delivered to health agencies and private clinicians this flu season.

The swine flu doses are being directed to those considered at highest risk for infection, including children older than 6 months; adults up to age 24; pregnant women; adults between ages 25 and 64 who have underlying medical conditions; and healthcare workers.

Because infants younger than 6 months cannot be vaccinated, their parents and caregivers are encouraged to get the inoculation.

Initial studies of the swine flu inoculation have indicated no major side effects.

“The vaccine has a very good safety profile,” Fielding said.

“It’s made the same way the seasonal vaccine is made.”

L.A. County will begin holding free swine flu shot clinics for the high-priority populations who have no regular source of healthcare on Oct. 23.

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ron.lin@latimes.com