What is a Flu Shot?
A flu shot, or influenza vaccination, is an annual immunization that protects against the most common strains of influenza virus expected to circulate during the upcoming flu season. The vaccine works by exposing your immune system to inactivated (killed) or weakened flu viruses, allowing your body to develop antibodies without actually causing the illness. These antibodies provide protection if you're later exposed to the actual flu virus. Because flu viruses constantly change and different strains predominate each year, the flu vaccine is updated annually, which is why you need a new flu shot each fall. Getting your annual flu shot is one of the simplest and most effective ways to protect yourself, your family, and your community from this potentially serious respiratory illness.
Why is it Important?
Influenza is far more than just a bad cold—it's a serious respiratory infection that hospitalizes hundreds of thousands of Americans and causes thousands of deaths each year, particularly among young children, older adults, pregnant women, and people with chronic health conditions. Even healthy individuals can become severely ill with the flu. The flu shot significantly reduces your risk of getting influenza and, if you do contract the virus despite vaccination, typically results in much milder symptoms and fewer complications. Beyond protecting yourself, getting vaccinated helps create community immunity that protects vulnerable individuals who cannot receive the vaccine or whose immune systems may not respond fully to vaccination, including infants too young to be vaccinated and people undergoing cancer treatment. For individuals with chronic conditions like heart disease, diabetes, or lung disease, the flu can trigger serious complications such as pneumonia, hospitalization, or worsening of underlying conditions, making vaccination especially critical. Additionally, preventing the flu helps you avoid missing work or school and reduces the strain on healthcare systems during flu season.
What to Expect
Getting a flu shot is a quick and straightforward process that typically takes just a few minutes. The vaccine is administered as a simple injection, usually in the muscle of your upper arm. You may experience minor side effects such as soreness at the injection site, low-grade fever, or mild muscle aches for a day or two afterward—these are normal signs that your immune system is responding to the vaccine and building protection. It's important to understand that the flu shot cannot give you the flu because it contains inactivated virus. It takes about two weeks after vaccination for your body to develop full immunity, so the earlier in the fall you get vaccinated, the better protected you'll be throughout flu season, which typically peaks between December and February but can last as late as May. Most insurance plans, including Medicare, cover the flu shot at no cost when administered at your primary care provider's office.
How to Prepare
Preparation for a flu shot is minimal. Inform your healthcare provider if you have severe allergies to any vaccine components, particularly egg protein (though most people with egg allergies can safely receive the flu vaccine). Let your provider know if you've had a severe allergic reaction to a previous flu shot or if you have a history of Guillain-Barré syndrome. If you're currently moderately or severely ill with a fever, you may be advised to wait until you've recovered, though minor illnesses like a cold typically don't prevent vaccination. There's no need to fast or make any special preparations—simply come ready for a quick injection. Consider wearing short sleeves or clothing with sleeves that roll up easily to provide access to your upper arm.
Have questions about flu shots? Contact Advanced Cardiovascular Specialists & Primary Care at (203) 334-2100 to schedule your appointment.
