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.