That the flu is nothing more than an annoying illness is one of the biggest misconceptions surrounding the disease. Although most people who catch the flu bug recover just fine, serious flu-related complications and death result every year, particularly among infants and young children, those with chronic medical conditions, the elderly, pregnant women and people who are obese. "No one should confuse influenza with a minor illness," stresses Mayo Clinic infectious diseases and vaccine expert Gregory Poland, M.D.

The most effective way to prevent infection is getting a seasonal influenza vaccination each year, say experts. Yet many people choose not to have the flu shot because of myths they believe about the vaccine. Dr. Poland dispels four of the most common:

Myth 1: Flu vaccines can give me the flu

False. Injectable flu vaccines are composed of pieces of inactivated flu proteins -- and it's impossible for them to "cause" flu. The nasal spray vaccine has live flu organisms weakened so they cannot multiply or cause disease.

Myth 2: Flu shots never work anyway, so why bother?

Also false. When there is a good match between the viruses causing disease and those in the vaccine, protection is excellent in otherwise healthy people. Protection is lower if you are unhealthy or in the frail elderly group. But vaccines are like seat belts: They are not perfect but they are the best protection we have against serious injury and death.

Myth 3: Flu vaccines are dangerous, especially for pregnant women

Also false. Concerns about pregnant women getting vaccinated began when women were advised not to get any kind of vaccination during pregnancy, Dr. Poland says. Today's flu vaccines are safe for expectant mothers and highly recommended. A recent large study demonstrated significant increases in maternal death among unvaccinated women infected with influenza. However, because they have not been studied in pregnant women, pregnant women should stay away from nasal flu vaccines, which do contain live, weakened flu virus, he says.

Myth 4: It's too late to get vaccinated

Again, false. While it's always better to get vaccinated before flu season begins -- it can take about two weeks for the vaccination to take full effect -- it's never too late to get a flu vaccine, Dr. Poland says. Even if you didn't get vaccinated and caught the flu, get a flu vaccine to protect yourself against the other strains that are circulating, he adds.