Getting a flu shot often protects you from coming down with the flu. And although the flu shot doesn't always provide total protection, it's worth getting.By Mayo Clinic Staff
This year's annual flu shot will offer protection against H1N1 flu virus, in addition to two other influenza viruses that are expected to be in circulation this flu season. A vaccine that protects against four strains of the virus will also be available, as will a high-dose flu vaccine for adults age 65 and older.
Influenza is a respiratory infection that can cause serious complications, particularly to young children, older adults and people with certain medical conditions. Flu shots are the most effective way to prevent influenza and its complications. The Centers for Disease Control and Prevention (CDC) recommends that everyone 6 months of age or older be vaccinated annually against influenza.
Here are the answers to common questions about flu shots:
Because the flu vaccine is produced by private manufacturers, its availability depends on when production is completed. For the 2015-2016 flu season, manufacturers have indicated shipments are likely to begin in July or August and continue throughout September and October until all vaccine is distributed. Doctors and nurses are encouraged to begin vaccinating people as soon as flu vaccine is available in their areas.
It takes up to two weeks to build immunity after a flu shot, but you can benefit from the vaccine even if you don't get it until after flu season starts.
New flu vaccines are released every year to keep up with rapidly adapting flu viruses. Because flu viruses evolve so quickly, last year's vaccine may not protect you from this year's viruses.
After vaccination, your immune system produces antibodies that will protect you from the vaccine viruses. In general, though, antibody levels start to decline over time — another reason to get a flu shot every year.
The CDC recommends annual influenza vaccinations for everyone age 6 months or older. Vaccination is especially important for people at high risk of influenza complications, including:
- Pregnant women
- Older adults
- Young children
Children between 6 months and 8 years may need two doses of flu vaccine, given at least four weeks apart, to be fully protected. Check with your child's health care provider.
Chronic medical conditions can also increase your risk of influenza complications. Examples include:
- Cancer or cancer treatment
- Chronic obstructive pulmonary disease (COPD)
- Cystic fibrosis
- Kidney or liver disease
Check with your doctor before receiving a flu vaccine if:
You're allergic to eggs. Some flu vaccines contain tiny amounts of egg proteins. If you have an egg allergy or sensitivity, you'll likely be able to receive a flu vaccine — but you might need to take special precautions, such as waiting in the doctor's office for at least 30 minutes after vaccination in case of a reaction.
There are also flu vaccines that don't contain egg proteins, and are Food and Drug Administration (FDA) approved for use in people age 18 and older. Consult your doctor about your options.
- You had a severe reaction to a previous flu vaccine. The flu vaccine isn't recommended for anyone who had a severe reaction to a previous flu vaccine. Check with your doctor first, though. Some reactions might not be related to the vaccine.
The flu vaccine comes in two forms:
A shot. A flu shot contains an inactivated vaccine made of killed virus. Because the viruses in this vaccine are killed (inactivated), the shot won't cause you to get the flu, but it will enable your body to develop the antibodies necessary to ward off influenza viruses.
The injection is usually given in a muscle in the arm. If you're between 18 and 64 years of age, you may also choose an in-the-skin (intradermal) vaccine, or you may prefer to have your vaccine delivered using a jet injector device, which uses a high-pressure, narrow stream of fluid to penetrate the skin instead of a needle.
A nasal spray. The nasal spray vaccine consists of a low dose of live, but weakened, flu viruses and is approved for use in healthy people 2 to 49 years of age who aren't pregnant. The vaccine doesn't cause the flu, but it does prompt an immune response in your nose and upper airways, as well as throughout your body.
Both the flu shot and the nasal spray help protect you from influenza. But there are differences to consider before deciding between the two.
|Administered through a needle or a jet injector device — you'll need an injection
|Administered through a spray — you won't need an injection
|Contains killed viruses — you can't pass the flu along to anyone else
||Contains weakened live viruses that won't give you the flu but that can, in rare cases, be transmitted to others
|Approved for use in people 6 months of age and older
||Approved for nonpregnant, healthy people ages 2 to 49 years
|Can be used in people at increased risk of flu-related complications, including pregnant women and those with chronic medical conditions
||Not given to those with chronic medical conditions or suppressed immune systems, or to children and adolescents receiving aspirin therapy
No. The flu vaccine can't give you the flu. But you might develop flu-like symptoms — despite getting a flu shot — for a variety of reasons, including:
- Reaction to the vaccine. Some people experience muscle aches and fever for a day or two after receiving a flu shot. This may be a side effect of your body's production of protective antibodies. The nasal vaccine can cause runny nose, nasal congestion, headache and sore throat.
- The 2-week window. It takes about two weeks for the flu shot to take full effect. If you're exposed to the influenza virus shortly before or during that time period, you might catch the flu.
- Mismatched flu viruses. In some years, the influenza viruses used for the vaccine don't match the viruses circulating during the flu season. If this occurs, your flu shot will be less effective, but may still offer some protection.
- Other illnesses. Many other diseases, such as the common cold, also produce flu-like symptoms. So you may think you have the flu when you actually don't.
How well the flu vaccine works can vary. The flu vaccine is generally more effective among healthy older children and younger adults. Some older people and people with certain medical conditions may develop less immunity after receiving a flu shot.
According to the CDC, in past flu seasons when the match between flu vaccine and circulating strains of flu virus is close, a flu shot is 71 percent effective in reducing flu-related hospitalizations among adults of all ages, and 77 percent effective among adults age 50 and older. The flu shot may reduce a child's risk by 74 percent.
With or without a flu shot, you can take steps to help protect yourself from the flu and other viruses. Good hygiene remains your primary defense against contagious illnesses.
- Wash your hands often and thoroughly with soap and water.
- Use an alcohol-based sanitizer on your hands if soap and water aren't available.
- Avoid touching your eyes, nose or mouth whenever possible.
- Avoid crowds when the flu is most prevalent in your area.
- Practice good health habits. Get plenty of sleep, exercise regularly, drink plenty of fluids, eat a nutritious diet, and manage your stress.
Aug. 19, 2015
- What you should know for the 2015-2016 influenza season. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/about/season/flu-season-2015-2016.htm. Accessed Aug. 11, 2015.
- Hibberd PL. Seasonal influenza vaccination in adults. http://www.uptodate.com/home. Accessed July 16, 2015.
- Munoz FM. Seasonal influenza vaccination in children. http://www.uptodate.com/home. Accessed July 16, 2015.
- Preventing the flu: Good health habits can help stop germs. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/protect/habits.htm. Accessed Aug. 11, 2015.
- Key facts about seasonal flu vaccine. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/protect/keyfacts.htm. Accessed Aug. 11, 2015.
- Vaccine effectiveness — How well does the flu vaccine work? Centers for Disease Control and Prevention. http://www.cdc.gov/flu/about/qa/vaccineeffect.htm. Accessed Aug. 10, 2015.
- Centers for Disease Control and Prevention, et al. Prevention and control of influenza with vaccines: Recommendations of the advisory committee on immunization practices, United States, 2015-16 influenza season. MMWR. 2015;64:818. http://www.cdc.gov/mmwr. Accessed Aug. 10, 2015.