Influenza (Flu)

The flu is a contagious viral illness that affects your nose, lungs and throat. While most cases are mild, like the common cold, the flu can cause severe lung infections like pneumonia. The influenza virus spreads through droplets in the air when someone with the flu coughs, laughs, sneezes or talks. You can catch the virus in several ways:

• Breathing in the droplets
• Touching used tissues
• Sharing drinking glasses, toothbrushes or utensils with someone who has the flu
• Touching a surface covered in droplets and then touching your eyes, mouth or nose

The flu affects up to 40 million people in the United States every year. It also leads to thousands of hospitalizations and deaths. Infections occur most often during “flu season” — between October and May — with most instances developing between December and February.

Three types of influenza virus — types A, B and C — cause the flu. Types A and B cause more severe symptoms. People usually develop Type A and B infections during flu season. Type C causes infections throughout the year, but symptoms are generally mild.

The flu, common cold and COVID-19 are all caused by different viruses. But they share similar symptoms, like runny nose and cough, so it can be difficult to tell them apart. Flu and COVID-19 symptoms are typically more severe than the signs you experience with the common cold. Getting tested will identify the cause of your infection and determine your best treatment options.

Anyone can get the flu. But some people are at higher risk for developing more severe illness from the infection. These factors put you at greater risk:

• Age (under 5 or over 65)
• Blood disorders like sickle cell disease
• Diabetes
• Heart disease
• Kidney disease
• Liver disease
• Long-term aspirin therapy if you’re under age 19
• Lung conditions like asthma or chronic obstructive pulmonary disorder (COPD)
• Obesity
• Pregnancy
• Stroke
• Weakened immune system

Hospitalizations to treat the flu are more common for American Indian, Alaska Native, Black and Latino patients. These groups have higher rates of asthma, diabetes, obesity and other chronic health conditions that can make the flu more severe.

Initially, the flu resembles the common cold. But flu symptoms develop much faster, and they make you feel much worse. Signs of the flu include:

• Body aches
• Chills
• Cough
• Diarrhea (typically only in children)
• Eye pain
• Fatigue
• Fever, usually higher than 100.4°F
• Headache
• Runny or stuffy nose
• Shortness of breath
• Sore throat
• Sweating
• Vomiting (typically only in children)

Our providers will first conduct a physical exam and assess your symptoms to determine if you have the flu. If it’s flu season, that may be enough to diagnose your condition. However, if our providers need more information to make a diagnosis, they may recommend additional tests. These tests include:

• Rapid influenza diagnostic tests (RIDTs). For this test, our providers gently swab the inside of your nose with a soft-tipped stick to collect a fluid sample. Within 10 to 15 minutes, an RIDT can detect the presence of influenza A and B. An RIDT isn’t as accurate as other tests, so you may have the flu even if your test result is negative.
• Rapid molecular assays (RMA). These tests also use a sample from your nose. Our providers will send your sample to the lab to determine if it contains genetic material from the flu virus. These test results are more accurate and available within 30 minutes.
• Reverse-transcription polymerase chain reaction (RT-PCR). RT-PCR is the most sensitive test for flu. Like an RMA test, an RT-PCR requires sending your sample to the lab for testing. It may take a few hours or days to get your result.

The flu usually goes away on its own if you get enough rest and fluids. Your symptoms should start to lessen within a week. To help you feel better, our providers can prescribe antiviral medications that reduce the severity of your infection and speed your recovery. They may suggest antiviral treatment if you:

• Are at risk for more severe illness
• Have an underlying condition
• Have severe symptoms
• Have had symptoms for 48 hours or less if your symptoms are mild
• Live with or care for someone at high risk for flu complications

You can also manage your flu symptoms with some healthy behaviors. Our providers recommend that you:

• Apply heat to achy muscles.
• Drink plenty of water to prevent dehydration.
• Get enough sleep.
• Take cough suppressants to reduce coughing and promote rest.
• Take a decongestant to relieve a runny or stuffy nose.
• Take an expectorant to help you cough up mucus and clear your lungs.
• Take pain relievers, like acetaminophen and ibuprofen, to reduce muscle aches.

To avoid spreading the virus, stay home for at least 24 hours after your fever and chills go away. Take your temperature to confirm it has gone down after you’ve stopped taking medication.

If you get the flu, you are also at risk of developing additional health complications. These problems can include:

• Central nervous system birth defects
• Ear infections
• Pregnancy loss (miscarriage)
• Pneumonia
• Sinus infections

You can’t always escape exposure to the flu virus, but you can take steps to prevent getting sick. An annual flu vaccine is the best way to avoid coming down with the flu. Vaccines are available as shots or as a mist.

The flu virus changes slightly every year, so you need to get vaccinated before each flu season. Even if you’re vaccinated, it’s still possible to get sick. But the vaccine reduces your risk of severe illness.

Practicing these good hygiene behaviors also reduces your risk:

• Avoid being around people who are ill.
• Consider wearing a mask when you’re sick and must be around others.
• Cover your nose and mouth with a tissue or your elbow when you cough or sneeze.
• Don’t share food, drinks or eating utensils and glasses.
• Don’t touch your eyes, face, nose or mouth.
• Wash your hands with warm water and soap or use alcohol-based hand sanitizer.

Most cases of the flu clear up on their own. However, you may need immediate medical attention if you have severe symptoms. Seek emergency care if you experience:

• Bluish lips, nails or skin
• Chest pain that lingers
• Confusion
• Dehydration that leads to little-to-no urination
• Difficulty breathing
• Dizziness that lingers
• Fever over 103°F
• Seizures
• Severe muscle pain or weakness
• Stomach pain that lingers
• Worsening of other health conditions