The flu season is from November to April, with most cases occurring between late December and early March, but the vaccine is usually offered between September and mid-November (and may be given at other times of the year).
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. Although you can get a flu shot well into flu season, it's best to try to get it earlier rather than later. However, even when there are only 2 or 3 months left in the flu season, it's still a good idea to get protection if the vaccine is available in your area.
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.
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.
Who Should Get the Flu Shot?
Federal health officials now urge flu vaccination for all kids 6 months of age and older (instead of just the youngest, as before). Although young tots (from 6 months to 5 years old) are still considered the group of kids who need the flu vaccine the most, updated guidelines from the CDC now recommend that all older kids and teens get it, too (as long as enough is available).
Other high-risk kids who should get the flu vaccine include those who:
- were born prematurely and are at increased risk of developing lung problems if they get influenza
- have chronic heart or lung disorders, including asthma
- have chronic diseases such as diabetes mellitus, kidney disease, severe anemia, or immune deficiency (including HIV/AIDS and immunosuppression caused by drugs)
- are on long-term aspirin therapy and may be at risk for Reye syndrome if they catch the flu
- live with someone in any of the high-risk groups above
High-risk adults who should get the flu vaccine include:
- those who have chronic lung or heart disorders
- those who have chronic diseases such as diabetes mellitus, kidney disease, severe anemia, or immune deficiency (including HIV/AIDS and immunosuppression caused by drugs)
- pregnant women
- residents of nursing homes and other facilities that care for people with chronic medical conditions
- health care workers and other employees of hospitals, nursing homes, and chronic care and other outpatient facilities who care for patients
- police, firefighters, and other public safety workers
- those planning to travel to the tropics at any time or to the Southern Hemisphere from April through September who did not receive a flu vaccine the previous year
- everyone 50 years of age or older
- out-of-home caregivers and household contacts of anyone in any of the high-risk groups
If you want to get the flu shot and aren't in the high-risk groups listed above, talk to your doctor about vaccine availability.
People who should not get a flu shot include:
- 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)
- infants under 6 months old
- anyone who's ever had a severe reaction to a flu vaccination (although most people do not experience any side effects from the flu shot)
- anyone with Guillain-Barré syndrome (GBS), a rare condition that affects the immune system and nerves
- anyone with a fever
Kids under 9 who get a flu shot for the first time will receive two separate shots a month apart. It can take about 1 or 2 weeks after the shot for the body to build up protection to the flu.
How the Flu Vaccine Works
Flu vaccines are available as a shot or nasal mist. Given as an injection, the flu shot contains killed flu viruses that will not cause the flu, but will prepare the body to fight off infection by the live flu virus. Getting a shot of the killed virus means a person is protected against that particular type of live flu virus if he or she comes into contact with it. The nasal mist vaccine contains weakened live flu viruses. Because it contains live viruses, the mist is not for people with weakened immune systems or certain health conditions.
Even if you or your child may have gotten the vaccine last year, that won't protect you from getting the flu this year because the protection wears off and flu viruses constantly change. That's why the vaccine is updated each year to include the most current strains of the virus.
The flu vaccine reduces the average person's chances of catching the flu by up to 80% during the season. Because the vaccine prevents infection with only a few of the viruses that can cause flu-like symptoms, it isn't a guarantee against getting sick. But even if someone who's gotten the shot gets the flu, symptoms usually will be fewer and milder.
Again, most people do not experience any side effects from the flu shot. According to the CDC, the flu shot rarely causes serious harm. Some of those vaccinated may have soreness or swelling at the site of the injection or mild side effects, such as headache or low-grade fever.
Although these side effects may last for a day, the flu can knock you off your feet for 2 to 3 weeks and can cause complications such as pneumonia, ear infections, sinus infections, and other respiratory problems.
If your child does have symptoms after getting the flu shot, put a warm compress on the injection site to ease soreness or swelling, and give acetaminophen or ibuprofen for headache or low-grade fever. Do not give your child aspirin unless your doctor instructs you to do so.
A common myth about the flu shot is that it can actually cause the flu. But the flu shot used in the United States is made from killed influenza viruses, which means that it's impossible to catch the flu by receiving it. However, because the nasal spray flu vaccine is made from live viruses, it may cause mild flu-like symptoms, including runny nose, headache, vomiting, muscle aches, and 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.
Other Preventive Measures
There's no guaranteed way — including being vaccinated — to prevent anyone from getting the flu. But precautions that can help protect you and your family include:
- avoiding large crowds whenever possible
- practicing good hand washing
- never picking up used tissues
- never sharing cups and eating utensils
- staying home from work or school when someone is sick with the flu
- covering your mouth and nose with a tissue when you cough or sneeze
Reviewed by: Larissa Hirsch, MD
Date reviewed: September 2008