The 2009 H1N1 flu (swine flu) pandemic is over, but the virus is still out there, making the rounds as a "regular" strain of seasonal influenza A. Here's an update on the flu vaccine.
When is the flu vaccine available?
The flu vaccine is generally offered in late summer and continues through October until all the vaccine has been distributed, which is typically before the late-fall to early-winter start of flu season. It takes up to two weeks to build immunity after a flu shot.
Will I still have to get a separate vaccine for H1N1 flu?
No. The flu vaccine is formulated each year to protect against the three influenza viruses expected to be the most common during that year's flu season. The 2012-2013 flu vaccine offers protection from both seasonal flu and H1N1 flu.
Who should get the flu vaccine?
In the United States, the flu vaccine is recommended for everyone beginning at 6 months of age. According to the Centers for Disease Control and Prevention, the flu vaccine is particularly important for older people, pregnant women and young children — the groups with the highest rates of flu complications.
Why does everyone need vaccination every year?
Influenza viruses mutate so quickly that they can render one season's vaccine relatively ineffective by the next season. Health officials use information gathered from around the world to determine which strains of influenza virus are most likely to be prevalent during the upcoming flu season. Manufacturers produce vaccine based on those recommendations.
Your body's immunity to influenza viruses (acquired through a natural infection or a flu shot) also declines over time, so an annual vaccination will help provide ongoing protection against flu.
How is the flu vaccine administered?
The flu vaccine comes in various forms:
- A shot. A flu shot contains an inactivated vaccine made of killed virus. The injection is usually given in the arm. Because the viruses in the 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.
- A nasal spray. Administered through your nose, the nasal spray vaccine (FluMist) consists of a low dose of live, but weakened, flu viruses. 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. The nasal spray vaccine is approved for healthy people between ages 2 and 49 who aren't pregnant.
Because a standard flu shot may not trigger as strong an antibody response in older people as it does in young adults, a higher dose vaccine has been approved for use in people age 65 and older.
Why do children need two doses of the flu vaccine?
Children younger than 9 years old require two doses of the flu vaccine, spaced at least four weeks apart, if it's the first time they've been vaccinated for influenza. That's because children don't develop an adequate antibody level the first time they get the vaccine. If a flu vaccine shortage occurred and your child couldn't get two doses of vaccine, one dose might still offer some protection.
Who should not get flu vaccine?
Check with your doctor before receiving a flu vaccine if:
- You're allergic to eggs. The flu vaccine contains tiny amounts of egg protein. 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.
- 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 Food and Drug Administration recently approved a flu vaccine (Flucelvax) produced using cultured animal — not egg — cells. This vaccine is approved for people ages 18 and older.
Key facts about human infections with variant viruses (swine origin influenza viruses in humans). Centers for Disease Control and Prevention. http://www.cdc.gov/flu/swineflu/keyfacts-variant.htm. Accessed Jan. 25, 2013.
- Key facts about seasonal flu vaccine. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/protect/keyfacts.htm. Accessed Jan. 25, 2013.
- Recommended composition of influenza virus vaccines for use in the 2012-2013 Northern Hemisphere influenza season. World Health Organization. http://www.who.int/influenza/vaccines/virus/recommendations/2012_13_north/en/index.html. Accessed Jan. 25, 2013.
- Centers for Disease Control and Prevention, et al. Prevention and control of influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP) - United States, 2012-13 influenza season. MMWR.2012;61:613. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6132a3.htm?s_cid=mm6132a3. Accessed Jan. 25, 3013.
- Centers for Disease Control and Prevention, et al. Prevention and control of influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2011. Morbidity and Mortality Weekly Report. 2011;60:1128. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6033a3.htm?s_cid=mm6033a3_w. Accessed Jan. 25, 2013.
- Steckelberg JM (expert opinion). Mayo Clinic, Rochester, Minn. Jan. 31, 2013.
- FDA approves first seasonal influenza vaccine manufactured using cell culture technology. U.S. Food and Drug Administration. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm328982.htm. Accessed Jan. 25, 2013.