Although the flu season lasts from November until April, with most cases occurring between late December and early March, the flu vaccine is usually offered between September and mid-November. Getting the shot before the flu season is in full-force gives the body a chance to build up immunity to, or protection from, the virus.

Even though it's ideal to get vaccinated early, the flu shot can still be helpful later. Even as late as January, there are still 2 or 3 months left in the flu season, so it's still a good idea to get protection.

In times when the vaccine is in short supply, certain people need it more than others. The Centers for Disease Control and Prevention (CDC) often will recommend that certain high-risk groups be given priority when flu shot supplies are limited. Call your doctor or local public health department about vaccine availability in your area.

Who Should Get the Flu Shot?

People over age 50 and all children and teens between 6 months and 18 years of age (especially those between 6 and 59 months) should get the flu vaccine.

Other high-risk groups include:

• women who will be pregnant during the flu season
• anyone who lives or works with infants under 6 months old
• residents of long-term care facilities, such as nursing homes
• any adult or child with chronic medical conditions, such as asthma
• health-care personnel who have direct contact with patients
• children ages 6 months to 18 years on long-term aspirin therapy
• out-of-home caregivers and household contacts of anyone in any of the high-risk groups

Ideally, kids and adults should be immunized in October so they're adequately protected before flu season hits. Kids under 9 who get a flu shot for the first time will receive it in two separate shots a month apart. It can take 1 to 2 weeks for the flu shot to become effective, so it's best to get vaccinated as soon as possible if your doctor thinks it's necessary.

Those Who Should Not Get a Flu Shot

Those who should not get a flu shot include:

• infants under 6 months old
• anyone who's severely allergic to eggs and egg products (ingredients for flu shots are grown inside eggs, so tell your doctor if your child is allergic to eggs or egg products before he or she gets a flu shot)
• anyone who's ever had a severe reaction to a flu vaccination
• anyone with Guillain-Barré syndrome (GBS), a rare medical condition that affects the immune system and nerves
• anyone with a fever

A non-shot option, the nasal mist vaccine, is now available, but because it contains weakened live flu viruses it is not for people with weakened immune systems or certain health conditions. The nasal mist vaccine is only for healthy, non-pregnant people between the ages of 2 and 49 years. Check with your doctor to see if your child can — or should — get this type of flu vaccine.

Are There Side Effects?

Most people do not experience any side effects from the flu shot. Some have soreness or swelling at the site of the shot or mild side effects, such as headache or low-grade fever.

Where Can My Family Get Flu Shots?

Flu shots are available at:

• many health care settings, including doctors' offices and public, employee, and university health clinics
• some pharmacies
• some supermarkets
• some community groups

If you have an HMO insurance plan, be sure to check with your primary care doctor before having your kids vaccinated outside the office, since most HMOs will pay for shots only if they're given through their plan.

Flu shots are covered by Medicare for senior citizens and are generally covered by insurance for people in other high-risk groups. Otherwise, flu shots may cost anywhere from $10 to $50. If you opt for the nasal mist flu vaccine, check to see if your insurance plan covers it.

Reviewed by: Steven Dowshen, MD
Date reviewed: August 2009

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