Each year, experts from the US Food and Drug Administration, World Health Organization, and the Centers for Disease Control and Prevention study virus samples collected from 136 national influenza centers in 106 countries to determine what three strains will be the most common during that particular season. These strains are then included in the annual vaccine.

According to the Centers for Disease Control and Prevention, older adults, pregnant women, young children, and people with certain health conditions like asthma, diabetes, and heart disease, are at greater risk for complications if they get the flu. Many individuals are eligible to receive the flu shot at little or no cost. Go to flu.gov for more information.

Nevertheless, it is possible to get the flu after being vaccinated. The vaccination works best on those who are young and healthy, but older adults and those with compromised immune systems may not be as well-protected. Additionally, the body takes approximately 2 weeks to build up immunity from the vaccine. People exposed before or within the two-week time period could possibly get the flu. And lastly, because the vaccination only covers 3 strains, it does not protect against all flu viruses.

The viruses in the flu vaccinated have been inactivated, so you will not get the flu from the shot. According to the CDC, "The risk of serious harm or death is extremely small. However, a vaccine, like any medicine, may rarely cause serious problems, such as severe allergic reactions. Almost all people who get influenza vaccine have no serious problems from it." The benefits far outweigh the risks.

Certain people, however, should not be vaccinated without consulting a physician first. These include:

• Those who have severe allergies to chicken eggs
• People suffering from an illness with a fever
• People with a history of Guillain-Barre Syndrome
• Children younger than 6 months of age

The Myth of Vitamin C

Research suggests that intakes of 200 mg/day or more of Vitamin C will not reduce the incidence of illness. However, it may be helpful for those with marginal vitamin C statuses, such as elderly and smokers, or those exposed to extreme physical exercise or cold environments. Vitamin C may shorten the duration of the common cold, but it appears that taking it after the onset of the cold or flu is not beneficial.

To Exercise or Not to Exercise?

According to the National Institutes of Health, exercise has not been shown in research to prevent colds or the flu. However, exercise, along with a proper diet, can improve the immune system by helping the disease-fighting white blood cells in the body move from the organs into the bloodstream. This helps decrease your chances of getting a cold or the flu.

If you happen to get any sort of seasonal illness, whether it's a cold or flu, you should not exercise if you have chest congestion, hacking cough, upset stomach, body aches, fatigue, or widespread muscle aches. However, if you have only mild symptoms, such as a runny nose, nasal congestion, or sneezing, exercise could help by opening nasal passages. During this time, however, you should reduce the intensity and length of your exercise.

How to Prevent Sickness During Flu Season

There are several things you can do to prevent illness.

• Ensure that your immune system is in tip top condition - eat a healthy diet, get regular physical activity, manage stress and get plenty of rest (at least 7 hours of sleep a night for adults).
• At work or school, wash your hands often, especially after working with someone who may be ill and before eating.
• If you can't get to a sink on a regular basis, use an alcohol based hand sanitizer - but be aware that hand sanitizer is not as effective as washing your hands.