Flu epidemic waning nationwide, CDC says

(USA TODAY) -- The flu appears to be waning nationwide after an early start in December, the Centers for Disease Control and Prevention said Friday. Flulike-illness activity fell in the East but is rising sharply in the West. Forty-five children have died as a result of the flu since the season's start.

Nationally, 9.4% of deaths reported in CDC's 122 Cities Mortality Reporting System were due to pneumonia and influenza as of Jan. 26. That's above the epidemic threshold of 7.2%. The rate of deaths linked to pneumonia and flu the week before was 9.8%.

The week before it was 8.3%.

Nationally, the proportion of people visiting the doctor for influenza-like illness was 4.2% down from 4.3%the week before, CDC's FluView report showed. The baseline number for the year is 2.2%.

Flu remains "elevated" nationwide, with 42 states reporting widespread geographic influenza activity and seven reporting regional activity, CDC said. The previous week, 47 states had widespread activity.

Despite the downward tick, the flu continues to hit hard, especially in the West, and people are still dying from it across the nation. Flu rates are at the highest levels seen in the past four years in Los Angeles, according to the Los Angeles County Public Health Department.

This year's flu season got off to an early start, hitting the East Coast especially hard in late December and early January. Several cities, including Boston and New York, declared flu emergencies.

Although to most sufferers flu is only a highly unpleasant way to spend a week, it can be very dangerous, especially to the elderly. Each year, between 3,000 and 49,000 Americans die from influenza-related causes, the CDC estimates.

There are currently three main flu strains circulating nationwide, with H3N2 the predominant one. It appears to be especially dangerous for the elderly. In Los Angeles, seven adults have died of flu, six of them over the age of 65. All had H3N2, the Public Health Department reported Thursday.

In San Diego, 19 people had died as of Tuesday, the majority of whom had underlying illnesses, according to the city's Health and Human Services Agency.

In Oregon, rates of flulike illnesses are high, though so far this season no children have died from flu.

The 2011-12 flu season was extremely mild, said William Schaffner, a professor of preventive Medicine at Vanderbilt University in Nashville. "We had the least flu we've ever had since we started recording. We couldn't believe how little flu we had."

This flu season has been harsher in part because people had little immunity due primarily to two factors: They simply didn't get sick last year, and the H3N2 flu strain that hasn't been seen much in recent years reappeared. "It has come out from under a rock and it's now dominant because there is a larger population of susceptible people" because no one's been exposed to it for several years, Schaffner said.