The Basics: Overview
Everyone age 6 months and older needs to get a flu vaccine every year. Seasonal flu vaccines are the best way to protect yourself and others from the flu.
For many people, the seasonal flu is a mild illness. But sometimes, the flu can be serious or even deadly.
- Is linked to serious infections like pneumonia
- Can make existing health problems worse (for example, long-term heart or lung disease)
- Can lead to hospitalization or death
Flu vaccines can help prevent people from getting sick with the flu — and lower the risk of hospitalization and death caused by the flu.
The flu spreads easily from person to person. So when you get a flu vaccine, you don’t just protect yourself. You also protect everyone around you.
When do I need to get the seasonal flu vaccine?
Get a flu vaccine by the end of October each year. After you get the vaccine, it takes about 2 weeks for your body to develop protection against the flu. That’s why it’s a good idea to get the vaccine before the flu starts to spread in your community.
If you don’t get the vaccine by the end of October, it’s not too late. Getting the vaccine later can still protect you from the flu. Keep in mind that flu season can last as late as May.
The Basics: Flu Symptoms
What is the flu?
The flu is caused by certain viruses that can infect your nose, throat, and lungs. It spreads from person to person when someone with the flu coughs, sneezes, or talks. It's also possible to get the flu by touching a surface or object that has flu virus on it and then touching your mouth, nose, or eyes.
Symptoms of the flu may include:
- Sore throat
- Feeling tired
- Runny or stuffy nose
- Muscle or body aches
- Fever or feeling feverish
- Having chills
For some people, the flu may also cause vomiting (throwing up) and diarrhea (frequent, watery poop). This is more common in children than adults.
Remember, not everyone with the flu gets a fever.
The Basics: Flu Vaccines
How is the flu vaccine given?
You can get the flu vaccine as a shot or as a nasal spray.
The best way to protect yourself and others around you is to get a flu vaccine every year.
Are there any side effects from seasonal flu vaccines?
For many people, getting a flu vaccine doesn’t cause any side effects. If it does cause side effects, they're usually mild and start soon after you get the vaccine. Side effects from flu vaccines usually last 1 to 2 days.
Side effects from the flu shot may include:
- Soreness, redness, or swelling where you got the shot
Side effects from the nasal spray vaccine may include:
- Runny nose
These side effects aren’t the flu. You can’t get the flu from flu vaccines.
The Basics: Am I at Risk?
Am I at high risk for serious complications from the flu?
For some people, the flu is more likely to cause serious illness that can lead to hospitalization or even death.
People at high risk for serious flu complications may include:
- Children under age 5 — and especially children under age 2
- Women who are pregnant or have had a baby in the last 2 weeks
- Adults age 65 and older
- People with some long-term health conditions (like asthma, diabetes, or heart disease)
- People with a weakened immune system (like people with HIV)
- People who live in long-term care facilities (like nursing homes)
- People from certain racial and ethnic groups, including people who are African American, Hispanic or Latino, and American Indian or Alaska Native
- People with obesity who have a body mass index (BMI) of 40 or higher
If you’re at high risk for serious flu complications, it’s especially important to get the vaccine before the flu starts to spread in your community. And if you care for or spend time with someone at high risk for serious flu complications, the flu vaccine can protect you both.
The Basics: Flu Medicine
Is there medicine that can treat the flu?
Yes. If you get sick with the flu, your doctor may prescribe medicines called antiviral drugs. Antiviral drugs can help you feel less sick and shorten the time that you’re sick. They can also help prevent serious flu complications.
If you’re at high risk for serious flu complications and you get flu symptoms, tell your doctor about your symptoms right away.
Antiviral drugs work best if you start taking them in the first 2 days after you get sick. But they may still help if you take them later on, especially if you’re very sick.
Take Action: Get a Flu Vaccine
Find out where to get a flu vaccine near you.
Flu vaccines are available in many locations. You can get a flu vaccine at a doctor’s office, health clinic, pharmacy, or your local health department. Your employer may also offer flu vaccines.
If you’re not sure where to start, call your doctor’s office or local health department.
What about cost?
Under the Affordable Care Act, insurance plans must cover seasonal flu vaccines. Depending on your insurance plan, you may be able to get a flu vaccine at no cost to you. Check with your insurance company to find out more.
Medicare may also cover flu vaccines at no cost. If you have Medicare, learn about Medicare coverage for flu vaccines.
If you don’t have insurance, you may still be able get a free or low-cost flu vaccine:
- Find a health center near you and ask about flu vaccines
- Find a free or low-cost vaccine program in your state
To learn more, check out these resources:
Take Action: Protect Yourself
Protect yourself and others from the flu.
Getting a flu vaccine is the first and most important step in protecting yourself from the flu.
Here are some other things you can do to help protect yourself and others from the flu:
- Stay away from people who are sick with the flu
- If you have the flu, stay home for at least 24 hours after your fever is gone (without using a fever-reducing medicine)
- Cover your mouth and nose with a tissue when you cough or sneeze, whether or not you have the flu — then throw the tissue in the trash
- Wash your hands often with soap and water — if soap and water aren’t available, use an alcohol-based hand sanitizer
- Try not to touch your nose, mouth, or eyes — this helps keep germs from spreading
- Clean surfaces and objects that may have flu germs on them, like doorknobs — use hot, soapy water or a household cleaner
Adults with the flu can spread it to others starting the day before they first feel sick — and up to 5 to 7 days after they first feel symptoms. Children may be able to spread the flu for even longer than 7 days.
Content last updated June 10, 2021
This information on the flu shot was adapted from materials from the Centers for Disease Control and Prevention.
Health Communication Specialist
National Center for Immunization and Respiratory Diseases
Centers for Disease Control and Prevention