Flu season is off and running, right on time, federal health officials said Friday.
Every state is reporting influenza outbreaks, and it looks a little worse than last year's relatively mild season looked at this point, according to the Centers for Disease Control and Prevention.
Flu is most widespread in the northwest — California, Washington, Oregon and Idaho — and in parts of the northeast and mid-Atlantic, the CDC reported in its weekly look at the virus.
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Some hospitals in Washington state have been hit hard, with people suffering from flu and other winter infections.
"It's been very busy. The hospital's been at capacity," said Malloree Fontanilla, a registered nurse who runs the emergency center at Providence St. Peter Hospital in Olympia, Washington.
"We have had a very full emergency center," Fontanilla told KING television.
That's not unusual for flu, and there are other viruses and bacterial infections in the winter, also — from norovirus to the bacteria that cause strep throat.
Flu usually hits the very young and the very old the hardest. Depending on the season, it kills anywhere between 4,000 and 50,000 people a year in the United States. Because each flu case is not counted, public health experts have to estimate flu's toll, and don't get a good picture until the end of the season.
"So far in the 2016-2017 influenza season, Influenza A (H3N2) viruses have been identified most frequently in the U.S.," the CDC says.
This particular strain seems to make people sicker.
"If H3N2 viruses continue to circulate widely, older adults and young children may be more severely impacted," the CDC said.
It's still not too late to get a flu vaccine, the CDC says. The flu vaccines on the market deliver a cocktail to protect against three or four strains of flu.
"The activity now is not at all unusual," said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University who speaks on behalf of the National Foundation for Infectious Diseases. Flu season usually takes off strong in January in the U.S. and peaks in January and February.
Influenza can be diagnosed with a test but symptoms are usually clear. They include:
Flu is rarely an emergency but doctors say to get kids to an emergency room fast if they have these symptoms:
Adults need immediate medical help if they have:
Especially dangerous is if people have flu-like symptoms, seem to get better, and then symptoms return. That could indicate a second infection and needs quick treatment.