You are not invincible. Even if you're crazy enough to believe you can't get influenza, understand that you can spread the flu to other people. Even those you love. Even people who are at high risk for complications, like your newborn niece or your grandmother.
Influenza officially arrived in Arizona this week with confirmation of the first case in a 4-month-old in Maricopa County.
But confirmed cases are just a fraction of what's out there, public health officials say. And this first case, arriving right on schedule just before Thanksgiving, is an early warning of a flu season that doesn't usually hit its stride until January or February.
This year, Google predicted Arizona's first influenza case before health officials did. The search engine giant rolled out its Flu Trends program last week on Google.org, and it's proven to be remarkably accurate.
Flu Trends detects early signs of regional flu outbreak by tracking how often people search for keywords, like "flu symptoms." Flu Trends data, tested with the U.S. Centers for Disease Control and Prevention last season, could help doctors, hospitals and public health officials reduce the severity of an outbreak by giving more advanced warning.
"A couple of weeks ago we started to see an increase among Arizona Web users for the term 'flu.' And by golly, we got a flu case right after that," said Will Humble, deputy director for the Arizona Department of Health Services.
"It appears to be two weeks better than the traditional lab confirmation and surveillance techniques that we use."
Humble said health officials are focusing on getting children immunized because they're the ones who spread the flu. For the first time, the CDC is recommending the flu vaccine for children of all ages, except infants younger than 6 months.
The closer it gets to Arizona's full-blown flu season, however, the harder it is to find a flu shot as the mass immunization clinics in supermarkets and drug stores, ubiquitous during October, generally close up by Thanksgiving.
"A lot of people feel like they got past November and it's too late," said Jennifer Tinney, program manager for the Arizona Partnership for Immunizations. "For us, it's definitely not too late."
Tinney said her group was successful in persuading some clinics to stay open through December last year, but nurses sat around all day with no customers.
Doctors who give out flu shots during the fall should still have some left, Tinney said. Also, Healthwaves, located in Ace Hardware stores, is offering flu shots through December.
The Maricopa County Public Health Department also plans to run a flu shot clinic in January at the airport, as they did last year, using vaccine donated to the immunization program from area doctors.
The county expects to give out about 14,000 shots this fall, targeting underinsured and uninsured families at schools, clinics and community events.
Last season was particularly harsh. Flu was widespread in Arizona, the highest CDC designation, for eight consecutive weeks, through February and into March. Two children died, including one who contracted a staph infection linked to influenza.
Up to 20 percent of people get influenza each year. In Arizona, more than 4,000 are hospitalized and 700 people die.