It's official: flu season -- in the northern hemisphere, where flu hits between October to May -- has begun. (In the southern hemisphere, of course, it's the other half of the year, and in the tropics, one can catch the flu year-round.) Today I'll focus on the northern hemisphere, but the same ideas apply at different times in other locales.

Please note that this is general information, and not a substitute for medical advice; contact your own doctor with questions about your health.

The sources for the information below are: Medical Letter, Up To Date, the NIH's MedLine Plus, the Centers for Disease Control, and Lung USA.

Who should get a flu shot?
Generally, those wanting to reduce their chance of getting sick. It's especially recommended for the following high-risk groups:

- People aged 50 and older
- Women who are or will be pregnant during the flu season
- Adults and children 6 months and older with chronic heart, or lung conditions including asthma, metabolic diseases such as diabetes, chronic kidney disease, or weakened immune system such as with HIV or with medications, and any kind of brain or spinal cord disorders
- Children 6 months to 18 years who are on long term aspirin therapy
- All children 6-23 months of age
- All the contacts of people in these high-risk groups

Other than your doctor's office, try Flu Clinic Locator to see where you might be able to get a shot.

Who shouldn't get one?
- People with severe allergy to eggs
- People who currently have a fever
- Children less than 6 months old
- People who have had Guillane Barre syndrome (a paralytic condition) within 6 weeks of getting a flu shot in the past

When's best to get one?
It's optimal to get a shot in October or November (especially for the high-risk groups noted above), but you can also benefit in December or later.

Types of vaccines
- A flu shot, made from an inactivated vaccine, which contrary to popular belief cannot give you the flu.
- A flu nasal spray, an attenuated live vaccine. Because this can at least theoretically cause transmission, it should only be given to healthy people ages 5-49 who are not pregnant, not healthcare workers, or contacts of anyone who is immuno-suppressed.


Within about 2 weeks, the shot is fully effective, and usually the effect lasts for 6 months or longer. A protection rate of 50-80 percent is the norm.

Recognizable flu symptoms
These are usually more severe than cold symptoms, and include sudden onset of high fever (101 or higher), severe muscle aches, headache, cough, sore throat, and a general miserable feeling. Symptoms may last 2-7 days, but if complications such as pnuemonia occur, the course may be longer.

How to treat the flu
Treatment is mainly designed to reduce the symptoms with
- rest
- fluids
- acetominophen (like Tylenol) -- not aspirin, especially in those under 18, to avoid Reyes Syndrome, which is a serious neurological disease
- antiviral medications (most effective if started within the first 2 days of onset of symptoms)

Unless there is a secondary complication (e.g. ear infection, sinusitis), antibiotics are not typically prescribed. And the jury is out on alternatives such as Vitamin C or herbal products. (Recently, echinacea was shown to be ineffective for cold treatment.)

Here's hoping you can stay healthy this winter!