Who needs a flu shot?

With rare exceptions, everyone older than six months should be vaccinated, according to the U.S. Centers for Disease Control and Prevention.

It's especially important for people who are at risk for serious complications. They include infants, the elderly, pregnant women and those with chronic health issues such as asthma, diabetes or lung disease.

The kind of people likely to be found in hospitals, nursing homes and clinics, in other words.

That's why the CDC stresses the importance of flu shots for another group: People who live with or care for those at-risk groups.

So it makes perfect sense for Alexian Brothers Health System to require its employees to get vaccinated. It's a growing trend throughout the industry, in fact. More than half the hospitals in one nationwide poll required their workers to get flu shots.

Many of those hospitals have encountered resistance from employees or their unions. Sunday's Chicago Tribune profiled Carrie Calhoun, a critical care nurse who works for the Elk Grove Village, Ill.,-based Alexian Brothers. Calhoun has taken a stand that could cost her her job: She refuses to get the shot.

In a puzzling twist of logic, she compares her position to that of a patient who refuses lifesaving medical treatment. But Calhoun is not the patient in this scenario. And requiring her to get a flu shot is meant not just to prevent her from getting sick, but to protect the vulnerable patients she might otherwise infect.

A CDC campaign to get health-care workers vaccinated has had an impact. In a recent survey, 86 percent of doctors and 80 percent of nurses reported getting the shots last flu season. But the rate fell to about 67 percent when physician assistants, nurse practitioners and other health care workers were included.

Only about half of those who work in long-term care facilities were vaccinated. That's especially worrisome since those older than 65 account for about 90 percent of the 36,000 annual flu deaths.

Why didn't those workers get shots? According to the survey:

Some aren't convinced the vaccine works. Its effectiveness depends on the patient's age and overall health, and on how well the current vaccine matches that season's flu viruses. Overall, though, the CDC says higher vaccination rates lead to lower infection rates.

Some said they worried about side effects. Serious reactions are rare, and health-care workers know it. And because the vaccine contains a killed virus, you can't get the flu from a flu shot.

Some said they don't think they need it. Again, this is not only about the health-care worker but about the patients they care for.

News stories from around the country offer another explanation: Workers don't think their employer should be able to force them to have a medical procedure. If your employer can order you to inject or inhale a vaccine, the reasoning goes, what else might it require? Oh, stop.

It's not unusual or oppressive for an employer to require its workers to take steps to make a workplace safer or to preserve the integrity of the business. That includes everything from drug testing to dress codes.

Many professions enforce ethical codes that restrict employee behavior on and off the clock. Journalists, for example, aren't supposed to run for office or contribute to political campaigns. Construction workers must wear protective gear, and pilots and truck drivers are required to get a certain amount of sleep so they don't endanger themselves or others.

There's nothing wrong with an employer setting reasonable conditions to protect its business, its workers or its customers. A hospital isn't out of line when it tells its employees to get vaccinated - or get fired.