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. Vaccination before December is best since this timing ensures that protective antibodies are in place before flu activity is typically at its highest. CDC continues to encourage people to get vaccinated throughout the flu season, which can begin as early as October and last as late as May. Over the course of the flu season, many different influenza viruses can circulate at different times and in different places. As long as flu viruses are still spreading in the community, vaccination can provide protective benefit.
Once you get vaccinated, your body makes protective antibodies in about two weeks. However, children younger than 9 years old who are being vaccinated for the first time need a second dose 4 or more weeks later in order to be protected.
Does getting vaccinated against flu early in the season pose a risk that immunity may wane before the end of the season?
No. Flu vaccination provides protection against the influenza strains contained in the seasonal vaccine for the entire season. Vaccination can begin as soon as vaccine becomes available.
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.
Who Should Get Vaccinated?
On February 24, 2010 vaccine experts decided that everyone 6 months and older should get a flu vaccine each year starting with the 2010-2011 influenza season. 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
- People 50 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
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.
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.
Visit the CDC web site for Key Facts about Influenza (Flu) and Flu Vaccine.