Chances are that you or someone you know has been chained to the bed recently with fever, fatigue, sore throat and muscle aches.
That's because the current flu season is turning out to be a bad one, affecting more people than usual, starting earlier and covering a broader geographical area. Government health experts say 18 children, under age 18, have died because of the seasonal flu and 2,257 people had been hospitalized with flu symptoms through the end of 2012.
"The sense that everybody has is that there's been an extremely rapid increase in influenza," says Trish Perl,co-leader of a flu study encompassing about 100 clinics in several cities. She is also an epidemiologist for the Johns Hopkins Health System in Baltimore. "It has been relatively widespread across the United States."
The public should be concerned, says Gregory Poland, professor of medicine and infectious disease at the Mayo Clinic in Rochester, Minn.
"A decade ago, when we had widespread circulation (of the seasonal flu), we had 70,000 deaths in the U.S.," says Poland, who directs Mayo's Vaccine Research Group.
"We have this cultural thing in the U.S. about, 'Oh, it's just the flu.' I was telling a group yesterday, imagine in October I said, 'We expect a virus to be circulating in the U.S. and it will kill 30- or 40,000 Americans.' Can you imagine the panic that would ensue?"
For the fourth week in a row, the proportion of people seeing health care providers for flulike illness is above the national baseline, and jumped from 2.8% to 5.6% in that time, according to the Centers for Disease Control and Prevention in Atlanta. Last season's proportion peaked at 2.2%, the CDC reports.
Twenty-nine states plus New York City are now reporting high flulike activity, up from 16 states the week before, the CDC says. Forty-one states reported in the last week of December that flulike activity was widespread geographically, with that number up from 31 states the week before, according to the CDC.
During the last week of 2012, 7% of all deaths reported in 122 U.S. cities were due to pneumonia and the flu, according to the CDC. That figure is just below the epidemic threshold of 7.1% for the last week of the year.
The medical industry is concerned because this is the earliest flu season the U.S. has seen in the past 10 to 12 years, says Michael Jhung, an epidemiologist and influenza expert at the CDC.
Flu season usually peaks in January and February, according to the Flu.gov website maintained by the Department of Health and Human Services.
The predominant type of flu that is circulating is H3N2 Influenza A virus, which is making up 76% of the viruses reported, according to the CDC.
The outbreak has strongly affected the East and the South and is spreading westward, Poland says.
Perl reports from her studies that initially health professionals were seeing a lot of Influenza B, but now they are seeing mostly A as well as other respiratory illnesses, including respiratory syncytial virus or RSV.
H3N2 flu seasons tend to be more severe, Poland of the Mayo Clinic says.
On the ground, the outbreak has sent more people to doctors and hospitals with flu symptoms.
For instance, in Minnesota, 600 people were hospitalized because of the flu and four people died, Poland says. Among those who died was an otherwise healthy 17-year-old boy who was visiting the Twin Cities area from Texas, according to Poland.
The professor said he's hearing similar stories from colleagues around the country of people who are generally healthy being hit hard.
In Indiana, seven deaths have been associated with influenza, two in people younger than 18.
"It's not too late to get vaccinated, and the CDC encourages everyone who hasn't been to do so soon," Jhung says.
Enough vaccine has been produced and distributed so that everyone who wants a shot should be able to get one. He urges, though, that if people run into delays because of a run on vaccine, not to be discouraged.
"People ... may have to go to more than one pharmacy," Jhung says.
Perl says the outbreak also is a good opportunity for the public to remember that hand-washing and use of sanitizing gels can reduce infection rates by 30%.
"It's an opportunity for us to reinforce those basic things your mom always told you," she says.
By Melanie Eversley and Elizabeth Weise