More from Vitals:
The flu season may finally be picking up steam after the slowest start in nearly three decades, a new government report suggests.
The Centers for Disease Control and Prevention reports an uptick in the number of samples testing positive for the virus -- 10.5 percent in the first week of February versus 7.6 percent the week before.
That suggests that the flu season is just off to a late start, CDC researchers say. Interestingly, it’s only the second time in 29 years that the percentage of respiratory samples testing positive remained under 10 percent through January.
"The peak of flu cases most commonly occurs in January or February, but the timing can vary significantly year to year," says Dr Otto Yang, professor of medicine, division of infectious diseases, at the David Geffen School of Medicine at the University of California, Los Angeles.
Flu season generally hits as early as October and can continue as late as May.
"It's difficult to predict if this will overall be lower than other years, because we have not yet reached the peak yet," Yang says.
Another of the CDC’s indicators that suggests that flu activity is starting to pick up in certain areas around the country is the count of people who show flu-like symptoms. Two regions -- Central and Northwestern U.S. -- are reporting a bump in influenza-like illnesses above baseline for the first time this year. And California is now reporting widespread influenza activity, while Missouri, Texas and Virginia have been reporting localized upticks.
Yang suggests the flu is peaking first in California because of its coastal location. "I can only speculate, but California is a state with lots of people traveling in and out, including people from areas where flu typically starts its spread each season," Yang says.
That may bode ill for the rest of the country, says Dr. Richard Zimmerman, a professor of family medicine at the University of Pittsburgh School of Medicine. “It’s fairly common for the west to precede the east,“ he explains. “But that’s not always true.”
If you still haven’t gotten your flu shot this year, get vaccinated right away, the CDC recommends, and Zimmerman agrees.
“This is really the last chance to get vaccinated,” he says. “It takes anywhere from one to two weeks for the vaccine to become effective.”
Other than vaccination, stay at home when you're sick -- and cross your fingers that your colleagues or schoolmates do the same, Zimmerman says. (Although for those who don’t have any sick leave left -- or never had any in the first place -- that can be a tough call.)
The only other protection you have against the flu is regular hand-washing. But no matter how fastidious you are, hand washing can only do so much in face of a virus that is mostly spread through the air when people cough and sneeze.
Related:

Getty Images stock
Flu Near You, a new tracking system, uses individual reports of symptoms to monitor the spread of influenza.
Getting the flu may be miserable, but if there’s any comfort, it’s in the perverse pleasure of cataloging symptoms. The sneezing, the coughing, the aches and the chills. The sudden high fever. The terrible sore throat.
Usually, finding anyone to listen -- except for spouses bound by duty and a shared mortgage -- is a tough task.
But not this year.
Thanks to a just-launched effort that aims to track the spread of influenza in real time, flu sufferers now have a place where they can whine to their hearts’ content, all the while contributing to the public good.
It’s called Flu Near You, a human sentinel system that uses first-person reports to monitor the illness nationwide. Unlike other reporting systems, it relies on tallies of specific symptoms in specific places to gauge spread and severity of infection.
“We’re actually getting people to tell us that they’re sick,” said John Brownstein, an epidemiologist and assistant professor of pediatrics at Harvard Medical School, with joint appointments at Children’s Hospital Boston.
The project, a joint effort of Children's Hospital Boston, the Skoll Global Threats Fund and the American Public Health Association, already has attracted more than 2,000 people willing to report weekly how terrible they feel.
The point, said Brownstein is to speed up monitoring to better be able to predict when, where -- and, possibly, whom -- the flu will strike next.
“Automatically, you’ll see yourself where you are on the map compared to other people reporting,” he said. “You’ll be able to see other people who are sick around you.”

flunearyou.org
Participants register, and then agree to fill out weekly surveys that ask whether they’ve suffered flu symptoms such as aches, chills, fever and coughing in the past week, or whether they’ve had no symptoms at all. They’re also asked to report whether they’ve received flu shots.
Researchers already know that monitoring behavior can offer a heads-up for impending illness. Google Flu Trends, an analysis based on users’ search terms related to flu symptoms, lets experts detect flu at least two weeks faster than the laboratory-confirmed surveillance system used by public health officials, including the Centers for Disease Control and Prevention.
But Flu Near You could be even quicker, Brownstein said.
Early evidence suggests that a self-reporting system works. In Australia, the FluTracking project started in 2004 and now boasts 10,000 people online every week. Researchers there have used the tool to demonstrate the efficacy of seasonal vaccines and to respond quickly to small communities with high rates of self-reported illness. Ten countries in Europe participate in InfluenzaNet, which tracks illness there.
Organizers eventually would like to see tens of thousands or even hundreds of thousands of United States users enrolled in Flu Near You, populating the national map with little green, yellow or red pins depending on whether they’re well, showing a few symptoms or coming down with a full-blown case of the flu.
It’s taking a while to catch on, but there are some strong incentives, Brownstein noted. Members of the APHA, for instance, are now competing for $150,000 in prizes for individuals and groups who recruit thousands of flu reporters. The top prize, $25,000 will go to the member who amasses the most users above the minimum of 10,000 surveys. That’s equal to recruiting at least 200 people who complete the survey once a week for 50 weeks in the competition that started in October and runs for a year.
“Actually the nursing association is banding together and they’re way out in front,” Brownstein said.
Ordinary people however, will have to settle for the comfort of complaining to a willing audience -- and knowing their flu symptoms may benefit society as a whole.
“We hope the people recruited into the system are doing it for their civic duty,” Brownstein said.
When were you the sickest? Tell us on Facebook.
Related story:
New flu virus in 3 Iowa kids raises worries about wider spread

Centers for Disease Control and Prevention
A transmission electron micrograph shows some of the structural details of the H3N2 flu virus that infected patients in Indiana and Pennsylvania earlier this year. The virus was formed through the reassortment of two other flu viruses.
Three children in Iowa have come down with a new type of flu virus previously linked to pigs, but this time the bug appears to have been spread by people.
The children, who live in rural Webster and Hamilton counties, did not become seriously ill, said Dr. Patricia Quinlisk, medical director for the Iowa Department of Public Health. But the detection of the virus known as swine-origin A/H3N2 in patients who hadn't had contact with animals raises concerns about potentially greater spread of a new type of flu.
"We have pretty good evidence of person-to-person spread," Quinlisk said. "None of the children or anyone around them had exposure to swine, turkeys or other sources."
Officials with the Centers for Disease Control and Prevention had previously detected seven cases of people with the new H3N2 virus that appears to have acquired a gene that may make it more transmissible from H1N1, the flu that sparked the so-called swine flu pandemic in 2009. Flu viruses often swap genetic parts. Officials say the new virus was probably formed when a pig became infected with the H3N2 virus and the H1N1 virus at the same time.
The new bug has components of human, avian, H1N1 and swine flu viruses, all mixed together in what scientists call a recombinant virus.
The first new H3N2 case was identified in a child in Indiana in July, and has been followed by cases in Pennsylvania, Maine and, now, Iowa.
In the previous cases, however, the patients either had direct exposure with pigs, or exposure to a person who'd been around pigs. In the new cases, it appears that one of the children transmitted the flu to the other two, and none of them had any animal exposure, Quinlisk said. She declined to identify the children or their ages, saying only they were younger than 18. No further cases have been identified in the past week, she said.
The Iowa cases are nothing to panic about, health officials emphasized. The H3N2 flu causes symptoms similar to the regular seasonal flu, including fever, cough, fatigue, body aches and loss of appetite.
"People need to be most concerned about the regular, everyday seasonal flu," Quinlisk said.
But Iowa health officials are now testing samples of people with flu-like illness to detect further spread of the new bug. And CDC officials have asked states across the country to be vigilant in looking for it, said Dr. Joe Bresee, the agency's influenza and epidemiology branch chief.
The current seasonal flu vaccine being offered by doctors and clinics was not developed to protect against the H3N2 virus. It contains some antigens similar to a flu virus that circulated in the 1990s, so some people who had the flu then or were vaccinated could have some immunity, but it's not clear how much, Quinlisk said. The Iowa children apparently had not been vaccinated, she added.
With the new cases, CDC officials have confirmed 31 cases in the U.S. of the new swine-origin virus since 2005, including 10 with the H3N2 virus that carries the M gene from the 2009 H1N1 virus.
The best prevention for the new flu, as with any flu, is to wash hands frequently, cover coughs and sneezes and limit spread of germs by staying home when you're sick, health officials said.
Related stories:
Ouch! Does this year's flu shot hurt more?
Flu shot not as effective as thought (get one anyway)
Scared of shots? New flu vaccine has tiny needle