So there you are. Sick. You’ve valiantly tried to fend it off but finally succumbed to all the symptoms promoted on the TV cold/flu commercials, and now you’re down. Or at least you should be.

But there’s a looming deadline at work, you’re overwhelmed with projects, pressures from the boss. Sick leave is exhausted, and you can’t miss a day’s pay, so you soldier on, incurring fear and loathing from co-workers who treat you like you have a contagious disease — which, just so happens, you do.

And the great debate rages on: do you go to work sick or stay home?

“Stay home,” said Dr. Steve O’Brien, vice president of medical affairs at Alta Bates Summit Medical Center in Oakland. “Nobody wants a sick person coming into the office. Think about it. you know you don’t like it when someone comes in sniffling and coughing all over the place. so don’t do that to them.”

Seems like common sense for the common cold and flu season — after all, who wouldn’t prefer to stay home, slurp some soup and catch up on daytime TV? But in this economy, it’s often a rare luxury, and the health of one’s bank account sometimes comes first and people force themselves to the office. There’s even a newly coined word for it: presenteeism. (The opposite of absenteeism.)

Joseph Siti, a woodworker in Berkeley, has been sick with the flu at least four times this year but has to go into his shop to meet deadlines. “I own my own business, so if I stop, I don’t make any money, and I don’t know when the next job is coming in.”

Even during the 2009 H1N1 crisis, when the Centers for Disease Control told people with flulike symptoms to stay home, more than 8 million struggled to work sick between September and November that year, according to a report from the Institute for Women’s Policy Research.

“If a person doesn’t have interaction with other people, you can go to work,” said Amy Nichols, director of hospital epidemiology and infection control at UCSF Medical Center. “But if you are symptomatic and working with the public and sharing surfaces or handling things other people will handle, stay home. Definitely if you have a fever or feel hot/cold with chills, stay home at least 24 hours after the fever is gone.

“I don’t care what your job is, the world will not stop if you don’t go to work,” she said. “It’s critical for contagion control, to avoid the domino effect.”

Tanya Tomassini, a project controller for an IT company in San Ramon, knows all about those dominoes. She was to fly out on a trip to Europe the day before Thanksgiving, but a few days before that, a couple of co-workers came into the office — very sick co-workers. She tried to avoid them like the plague, but to no avail.

“I ended up with one of the worst flu bugs imaginable,” Tomassini said. “I had to change my nonrefundable flights, which cost me $400, and I was too sick to even spend Thanksgiving with my family. Long story short, if you’re sick, stay home!” she said. “You don’t realize how much you can affect someone unintentionally.”

Businesses want you to stay away, too, if you’re truly ill.

Michelle Mendoza, owner of Connect HR, a human resources consulting firm in San Jose, admits it’s a tough subject.

“Here in Silicon Valley, there’s that passion of wanting to work all the time, but if you stay home one or two days, you get better faster instead of having it drag out for a couple of weeks.”

Generally, most companies have some type of sick leave policy or PTO (paid time off) available, she said. “From an employer’s standpoint, there’s a big incentive to give workers time to get better faster. many provide on-site flu shots or incentives for workers to get shots at the drugstore. It costs the employer money, but it’s less costly than having multiple people out sick. Or working sick and losing productivity.”

Indeed, a report by researchers at Cornell University found that ill workers on the job could account for up to 60-percent of corporate health costs.

“Your level of productivity drops significantly when you’re under the weather, said physician and radio personality Dr. Dean Edell. “There was a study showing that driving ability is impaired when you have the flu, to the equivalent of having a couple of drinks. so imagine how that affects your efficiency at work if you’re foggy-headed, taking any cold or flu medications that impair cognition.”

The best thing you can do to keep from spreading disease — or getting it — is wash your hands and keep work surfaces clean, said Bay Area health and fitness expert Joanie Greggains. “Avoid close contact with others, especially those who might easily get the flu such as people with chronic medical conditions such as diabetes, asthma or heart disease, pregnant women, young children and infants.”

Oh, and stay home.

“You’re going to get much better much faster,” O’Brien said. “Do it for your co-workers, but do it for yourself, too.”

Good ‘home sick’ DVDs

(Fun, not too stressful and won’t make you think too hard)1. “Ferris Bueller’s Day Off”2. “Home Alone”3. “Ghostbusters”4. “The Princess Bride”5. “Roman Holiday”

Bad ‘home sick’ DVDs

(Not helpful to watch people dying of disease)1. “Contagion”2. “Terms of Endearment”3. “Outbreak”4. “The Andromeda Strain”5. “The Omega Man”