Seasonal Flu: Frequently Asked Questions (FAQS)
When should I get a flu vaccination?
CDC recommends that people get their seasonal flu vaccine as soon as vaccine becomes available in their community. Yearly flu vaccination should begin in September, or as soon as vaccine is available, and continue throughout the flu season which can last as late as May. This is because the timing and duration of flu seasons vary. While flu season can begin early as October, most of the time seasonal flu activity peaks in January, February or later. As long as flu viruses are still spreading in the community, vaccination can provide protective benefit.
Does flu vaccine work right away?
No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection. In the meantime, you are still at risk for getting the flu. That’s why it’s better to get vaccinated early in the fall, before the flu season really gets under way. Flu vaccines will not protect against flu-like illnesses caused by non-influenza viruses.
Does getting a flu vaccine early in the season mean that I will not be protected later in the season?
No. Flu vaccination provides protection against the influenza strains contained in the seasonal vaccine for the entire season. Studies do not show a benefit of receiving more than one dose of vaccine during a flu season.
Why should people get vaccinated against the flu?
Influenza is a serious disease that can lead to hospitalization and sometimes even death. Every flu season is different, and influenza infection can affect people differently. Even healthy people can get very sick from the flu and spread it to others.
Why do I need to get vaccinated against the flu every year?
Flu viruses change from year to year, which means two things. First, you can get the flu more than once during your lifetime. The immunity (natural protection that develops against a disease after a person has had that disease) that is built up from having the flu caused by one virus strain doesn’t always provide protection when a new strain is circulating. Second, a vaccine made against flu viruses circulating last year may not protect against the newer viruses. That is why the influenza vaccine is updated to include current viruses every year. Another reason to get flu vaccine every year is that after you get vaccinated your immunity declines over time and may be too low to provide protection after a year.
How do flu vaccines work?
Flu vaccines (the flu shot and the nasal-spray flu vaccine (LAIV)) cause antibodies to develop in the body. These antibodies provide protection against infection with the viruses that are in the vaccine.
Who Should Get Vaccinated?
Everyone 6 months and older should get a flu vaccine each year. The CDC’s Advisory Committee on Immunization Practices (ACIP) recommended “universal” flu vaccination in the U.S. to expand protection against the flu to more people.
While everyone should get a flu vaccine each flu season, it’s especially important that the following groups get vaccinated either because they are at high risk of having serious flu-related complications or because they live with or care for people at high risk for developing flu-related complications:
- Pregnant women
- Children younger than 5, but especially children younger than 2 years old
- Adults 65 years of age and older
- People of any age with certain chronic medical conditions
- People who live in nursing homes and other long-term care facilities
- People who live with or care for those at high risk for complications from flu
What types of flu vaccine are there?
There are two types of flu vaccines, the flu shot and the nasal-spray.
- The “flu shot” — an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions. There are three different flu shots available: a regular flu shot approved for people ages 6 months and older a high-dose flu shot approved for people 65 and older, and an intradermal flu shot approved for people 18 to 64 years of age.
- The nasal-spray flu vaccine — a vaccine made with live, weakened flu viruses that is given as a nasal spray (sometimes called LAIV for “Live Attenuated Influenza Vaccine”). The viruses in the nasal spray vaccine do not cause the flu. LAIV is approved for use in healthy* people 2 through 49 years of age who are not pregnant.
What flu viruses are included in the 2011-2012 flu vaccine?
- an A/California/7/2009 (H1N1)-like virus;
- an A/Perth/16/2009 (H3N2)-like virus; and
- a B/Brisbane/60/2008-like virus.
These are the same viruses that were selected for the Northern Hemisphere for the 2010-2011 influenza vaccine.