Flu vaccine protection lasts about one year. Other than children who are getting the flu vaccine for the first time, people only need one dose of flu vaccine each season.
Show All Answers
There are many options for the flu vaccine this year. Below is an overview of each option; click the link to learn more about each one.
If you have questions about any of these options, please talk with a doctor about what is right for you or your child.
Does Fluzone High-Dose offer better protection than the adjuvanted flu vaccine?
To date, there have been no randomized studies comparing Fluzone High-Dose with FLUAD (the adjuvanted influenza vaccine).
While seasonal influenza (flu) viruses are detected year-round in the United States, flu is most common during the fall and winter. The exact timing and duration of flu seasons can vary, but influenza activity often begins to increase in October. Most of the time flu activity peaks between December and February, although activity can last as late as May.
No. The flu shot is made from an inactivated influenza virus and cannot give you the flu.
"But my mom got sick..."
Some people experience body aches and fatigue for a short time after getting the flu shot, which is the body’s immune system responding to the vaccine.
It is also possible that you may be exposed to a flu virus shortly before getting vaccinated or during the 2 weeks it takes the body to develop an immune response after getting vaccinated. This exposure may result in you becoming ill with flu before the vaccine begins to protect you.
Unfortunately, we won’t know whether the flu vaccine is a good match to circulating flu viruses until well into the flu season. It’s not possible to predict with certainty if a flu vaccine will be a good match for circulating flu viruses.
A flu vaccine is made to protect against the flu viruses that research and surveillance indicate will likely be most common during the season. However, experts must pick which flu viruses to include in a flu vaccine many months in advance in order for flu vaccines to be produced and delivered on time.
CDC works to characterize about 2000 circulating flu viruses every year to compare them to the virus strains in the vaccine. This helps them understand the flu vaccine’s ability to produce an immune response in people. It also helps them decide what strains to include in the next season’s flu vaccine.
The number of pediatric deaths from influenza is required to be reported to public health in Arizona by state statute. Because there is no requirement to report influenza-related deaths in adults, we monitor adult deaths due to influenza and/or pneumonia as a substitute.
People who die from influenza typically do not die from influenza itself. They usually die from the bacterial pneumonia that can occur as a complication to influenza.
Influenza viruses are constantly changing. They can change in two different ways:
One way they change is called “antigenic drift.” These are small changes in the genes of influenza viruses that happen continually over time as the virus replicates. But these small genetic changes can accumulate over time and result in viruses that are look different to the body’s immune system. When this happens, the body’s immune system may not recognize those viruses. That is why the flu vaccine composition must be reviewed each year and updated as needed to keep up with changing viruses.
The other type of change is called “antigenic shift.” Antigenic shift is an abrupt, major change in the influenza A viruses, resulting in a completely different virus that infects humans. Such a shift occurred in the spring of 2009, when an H1N1 virus with a new combination of genes emerged to infect people and quickly spread, causing a pandemic. When shift happens, most people have little or no protection against the new virus.
While influenza viruses are changing by antigenic drift all the time, antigenic shift happens only occasionally. Type A viruses undergo both kinds of changes; influenza type B viruses change only by the more gradual process of antigenic drift.
You should get a flu vaccine before flu begins spreading in your community. It takes about two weeks after vaccination for antibodies that protect against flu to develop in the body. CDC recommends that people get a flu vaccine by the end of October.
Children who need two doses of vaccine to be protected should start the vaccination process sooner, because the two doses must be given at least four weeks apart.
Does my child need two doses?
No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection. That’s why it’s better to get vaccinated by the end of October, before the flu season really gets under way.
Some people who get vaccinated may still get sick. However, flu vaccination has been shown to reduce severity of illness in people who get vaccinated but still get sick.
The vaccine has also been shown to reduce deaths, intensive care unit admissions, and length of hospitalization among hospitalized flu patients.
A 2017 study was the first of its kind to show that flu vaccination can significantly reduce a child’s risk of dying from influenza.
A flu vaccine is needed every season for two reasons:
For the best protection, everyone 6 months and older should get vaccinated annually.
To find a flu vaccine for you or your child, please visit the flu page and use the Flu Vaccine Finder widget that has options for free flu shots for children and other flu shot options for adults.