Understanding the Flu: Symptoms, Prevention, and Treatment

What is the flu?

The flu (short for influenza) is a contagious respiratory illness caused by the influenza virus. It affects your nose and throat and can even affect your lungs and how you breathe.

What are the most common flu symptoms?

When you have the flu, you may experience some or all of the following symptoms:¹

• Fever
• Cough
• Sore throat
• Runny or stuffy nose
• Body aches
• Headache
• Fatigue
• Chills
• Vomiting and diarrhea (more common in children)

These symptoms can appear suddenly and may be mild or severe. Not everyone with the flu will get all symptoms. If you feel sick, stay home and rest so you don’t spread the flu to others.

How does the flu spread?

The flu spreads very easily through droplets from someone who coughs, sneezes, or talks near you. You can also get it by touching something with the virus on it and then touching your mouth or nose.¹

Who is most likely to get very sick from the flu?

While most people recover from the flu in a week or two, some people are at higher risk of getting very sick. These groups include:²

• Children under age five, especially babies.
• People 65 and older.
• People with chronic health conditions such as asthma, diabetes, or heart disease.

People in these groups are at higher risk of getting more serious symptoms, including pneumonia or infections in the lungs, ears, or sinuses. They might need to go to the hospital. In some cases, the flu can lead to a life-threatening illness. If you’re in a high-risk group, it’s extra important to try to avoid getting the flu and to see a doctor if you feel sick.

What are the different types of flu?

There are four main types of flu viruses in humans: A, B, and C.³

• Type A is the most common type of flu. It spreads easily and can make people very sick.
• Type B is the second most common type of flu. Symptoms are very similar to flu A but may not be as severe.
• Type C is less common than flu A and flu B. It causes mild symptoms and doesn’t spread as easily.

Each year, flu shots are made to protect against the most common strains of flu A and flu B. Getting vaccinated helps lower your chances of getting very sick.

How can you prevent the flu?

The best way to reduce your chances of getting the flu or getting serious flu-related complications, is by getting a flu vaccine each year. The flu vaccine is updated annually to protect against the most common strains of the virus. Flu shots are safe and effective.⁴ Flu shots are a part of preventive care services. One flu shot is covered per year under most health plans.

There are other things you can do to try to prevent the flu:

• Wash your hands.
• Stay home if you're not feeling well.
• Cover your mouth and nose when you cough or sneeze.
• Clean and disinfect frequently touched objects and surfaces.
• Support your immune system by eating a balanced diet, getting enough sleep, and exercising regularly. 

What are common side effects from the flu vaccine?

The flu vaccine is safe, but common side effects might include:⁵

• Soreness in the arm where you got the shot
• Redness or swelling around the vaccine spot
• A mild fever
• Body aches

These side effects are usually mild and go away quickly. Talk to your doctor about managing side effects with over-the-counter pain relievers, such as ibuprofen or acetaminophen. It’s important to know that the flu vaccine cannot give you the flu.⁵

How can you treat the flu?

If you get the flu, here are things you can do to feel better.

• Rest - Sleep and take it easy so your body can fight the virus.
• Stay hydrated - Drink lots of water, juice, or clear broths to keep your body hydrated.
• Take medicine - Over-the-counter medicine like acetaminophen and ibuprofen can help with fever and pain.
• Ask your doctor - Some people may need antiviral medicine like Tamiflu. It works best if you take it within two days of getting sick.

If you have a high fever (over 103°F), have trouble breathing, can't keep fluids down, or symptoms are getting worse instead of better, make sure to talk to your doctor or visit an urgent care center.

Additional Flu FAQs (Frequently Asked Questions)

How do I know if I have the flu vs. a cold or COVID-19?

It can be tricky to know the difference between the flu, a regular cold, or COVID-19 since the symptoms can be similar. The only way to know for certain is by taking a test. You can do both flu and COVID-19 tests at home with a nasal swab.⁶

Who should get the flu vaccine?

Everyone six months and older should get a flu shot every year.⁵

When is the best time to get the flu vaccine?

The best time to get the flu vaccine is in the fall (September or October), before flu season starts. However, flu vaccines are still worth getting even after October. Late vaccination is better than no vaccination.⁵

Where can you get the flu vaccine?

You can get the flu vaccine at your doctor’s office, a pharmacy, or a health clinic. If you're a Cigna Healthcare member, you can view a list of pharmacies that offer the flu shot [PDF].

What are the different types of flu vaccines?

There are different types of flu vaccines such as shots (injections) and nasal sprays. Talk to your doctor about which one is right for you.

How much does the flu vaccine cost?

If you have health insurance, one flu vaccine is covered per year as preventive care.

If you don’t have health insurance, the flu vaccine can range from $20 to $130 out-of-pocket.⁷ The cost may depend on a few factors, such as where you live, what kind of facility you go to, and what type of vaccine you get.

Why should I get the flu vaccine?

Getting a flu shot is a smart way to stay healthy. It can:⁵

• Stop you from getting sick - The vaccine helps your body fight off the flu virus.
• Makes symptoms milder - If you do get the flu, the shot can help you feel less sick.
• Help protect others - When you get vaccinated, you help keep people around you safe, especially babies, older adults, and others who could get extremely sick from the flu.