NEW YORK ( MainStreet) — The flu is particularly virulent this year and reports of vaccine shortages are being filed from around the nation. The Centers for Disease Control and Prevention reports 35 states are now experiencing widespread activity and 20 states are reporting high levels of influenza-like illness. The swine flu, or H1N1, seems to be the primary culprit.

"Anyone aged six months and older who has not gotten a flu vaccine yet this season should get one now," the CDC says. "All flu vaccines are designed to protect against H1N1 viruses."

More than 200,000 people are hospitalized for flu-related complications each year.

"Vaccination is the most important way to keep yourself from getting sick with influenza," says Gary A. Noskin, MD, senior vice president and chief medical officer at Northwestern Memorial Hospital in Chicago. "Patients who are reluctant to get the flu shot often believe that it is unnecessary for them or that it may actually cause the flu, neither of which is correct. We know that between 5 to 20% of the population contracts the flu each year, and the majority of them have not been vaccinated."

The flu shot cannot give you the flu – but how many of us have anecdotal evidence that seems to contradict that? On a personal level, my brother has missed work for a week. When I asked him what was up, his email reply was, "Been sick, five days. Thought I had the flu, but think it was the flu shot."

Sound familiar?

Noskin says it is possible for someone to get the flu shot and then get sick -- if he or she was already infected with the virus. He adds that while some "mild flu-like symptoms may occur afterward," these symptoms are rare.

"The vaccination cannot give someone the flu," he insists. "Every flu shot contains a form of the virus that is inactive and no longer infectious."

Kelly Moore, MD, MPH, director of the Tennessee Immunization Program, agrees. She says misconceptions about flu shots prevent many individuals from benefitting from the protection the immunizations provide, putting people at risk of potentially serious illness.

"The rumor we hear most – that getting immunized will give you the flu – probably began for a couple of reasons," Moore says. "First, it takes up to two weeks after the vaccine is given before you are protected, so it's possible for someone to get the flu before the vaccine can start offering protection. Although some vaccinated people will still come down with influenza naturally despite vaccination, at this time of year, many others may think they had the flu when they had a flu-like illness caused by something else."

Noskin adds that stemming the spread of the virus is important in order to protect friends, co-workers and family members from being infected. "You can start spreading the flu up to 24 hours before you develop symptoms or even know you have been infected," he says.