Question: When should you get a flu vaccine (flu shot), and how long does it last?
Answer: Traditionally, we've given influenza vaccines during a tight period of time in October and November of each year, mostly because we were trying to focus on high-risk groups. As we've gradually expanded to wanting to immunize more and more people in the United States, we've also had to expand the time period when influenza vaccine has been available. And fortunately, the pharmaceutical companies that make these products have been able to make more and more of the products each year and have been able to get them into the market earlier and earlier. We strongly encourage everybody to start getting influenza vaccine as soon as it's available in their market.
Little children in particular, since they require two doses of the vaccine in their first year of receiving it, really need to get started as soon as possible. Most communities should have influenza vaccines starting to become available in September, and certainly by October almost everyone should have access to the vaccine. We would encourage everyone who is interested in preventing themselves from getting influenza to contact their provider and find out when influenza vaccine will be available at their office and in their market so they can schedule a time and become vaccinated as soon as possible.
The immunity from the vaccine actually lasts for a substantial period of time. In past years people used to be concerned that the immunity would fade but we have much better data now that supports that immunity actually can extend throughout the influenza season into the spring, and in many cases actually into the following year. Still, we want everybody to get influenza vaccine each and every year since the vaccine is slightly different from year to year and you want maximal protection for that upcoming flu season as quickly as possible and as early as possible.