The most effective way to decrease complications and reduce the impact of the flu is to give a preventative vaccine shot. The North American vaccine is developed each year to work against three strains of influenza virus, based on trends seen in the Southern Hemisphere. The best time for vaccination is early October to mid-November.
Anyone who is in contact with high-risk populations (including healthcare workers) should also receive the vaccine. People who are not part of the high-risk groups but just want to avoid the flu can also get vaccinated. If you are currently sick with a low-grade fever, experts suggest that you should wait until you are better before you get the vaccine. If you do not have a fever, you do not have to wait.
Vaccinations are not recommended for children less than 6 months of age because their immune systems are too immature for the vaccine to work properly. People who have an egg allergy, an allergy to thimerosal (a preservative used in the vaccine), a history of allergic reactions to the flu vaccine, or a history of Guillain-Barré Syndrome should not receive the vaccine.
There are many myths about what predisposes a person to catch a cold and what makes one person catch more colds than another. Factors that may increase the risk of catching a cold are fatigue, emotional stress, smoking, mid-phase of the menstrual cycle, and nasal allergies. Factors that do not increase the risk of catching a cold include cold body temperature (i.e., being out in the cold), health status, nutritional status, and enlarged tonsils.
Echinacea may help prevent colds, but research studies are not conclusive. Vitamin C does not appear to protect people from catching colds, but it can shorten the duration of a cold by half a day.