You and the Flu

Different types of flu

There are four types of influenza viruses: A, B, C, and D. Only influenza A, B, and C affect humans (flu D impacts cattle). It's possible to have two types of flu at the same time. It's also possible to get infected with one type after having the other. 

Flu A is usually more severe than the other types of flu and can lead to more complications, especially in adults. Additionally, flu A viruses mutate, or change, more rapidly than flu B viruses. 

Flu B is generally milder than flu A, but it can still cause serious illness in vulnerable populations like children and older adults. Children are more susceptible to flu B, but it can affect all age groups.

Flu C typically presents as a mild respiratory illness, and sometimes has no symptoms at all. It is not thought to cause widespread outbreaks like flu A and B.

Stomach flu, or gastroenteritis, is not the same as influenza (although you can have them at the same time). Stomach flu is caused by a virus, like norovirus or rotavirus, that attacks your intestines and leads to nausea, vomiting, and diarrhea. Influenza is a virus in your respiratory tract that affects your lungs.

Flu symptoms

Flu symptoms often appear suddenly and can be severe, especially in the first few days. Common symptoms of the flu include:

• Fever and chills

• Sore throat and cough

• Runny nose and congestion

• Headache

• Muscle aches

• Extreme fatigue

Some individuals may also experience headaches, vomiting, or diarrhea, especially children. 

Is it the flu, a cold, or COVID?

How do you tell if you have the flu, a cold, or COVID? Getting tested is the only way to know for sure, but there are sometimes differences:

Treating the flu

Influenza can often be managed with a combination of at-home care and, if necessary, medication that treats symptoms. Antiviral drugs can help lessen the severity and duration of the flu, but they must be started within the first few days of illness to be effective. 

Rest. Get plenty of rest to allow your body to focus on fighting the infection. 

Hydration. Drink plenty of fluids, such as water, broth, or herbal tea, to prevent dehydration. 

Medications. Over-the-counter medications like acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) can help reduce fever and body aches. Cough medicine, either over-the-counter or prescription, can help relieve your cough so you can rest.

Humidify. Using a humidifier can help relieve congestion and cough.

No antibiotics. Since the flu is caused by a virus, antibiotics are not effective against it and should not be used to treat it. However, the flu can sometimes cause secondary infections, like sinus infections. These may be treated with antibiotics.

Be careful with kids. Aspirin should not be given to children or teenagers with flu symptoms due to the risk of Reye's syndrome. 

Seek immediate medical attention if you experience severe symptoms like difficulty breathing, persistent vomiting, or worsening symptoms.

Vulnerable Groups

Some people are more susceptible to developing complications from the flu due to other health conditions they have. Those with the highest chance of having dangerous complications of the flu are:

• Over age 65

• Young children

• People with asthma and lung disease

• People with weaker immune systems

• Those who have had an organ transplant or are on chemotherapy

Stopping the spread

The flu spreads through infected droplets that enter the environment when sick people cough, sneeze, and touch surfaces. When you get infected with the flu, you can spread it to others even before your symptoms begin, and for five to seven days after your symptoms start. 

To avoid spreading the flu:

• Stay home until you have been fever-free for at least 24 hours.

• Wash your hands frequently with soap or use an alcohol-based hand sanitizer.

• Cover your mouth and nose with a tissue when you sneeze or cough.

• Clean frequently-touched surfaces.

Resources:

• INFLUENZA (FLU) Flu and You. Centers for Disease Control and Prevention.

• 2022-2023 U.S. Flu Season: Preliminary In-Season Burden Estimates. Centers for Disease Control and Prevention.

• Patient education: Influenza symptoms and treatment (Beyond the Basics). UpToDate.

• Patient education: Pneumonia in adults (Beyond the Basics). UpToDate.

• Influenza Antiviral Medications: Summary for Clinicians. Centers for Disease Control and Prevention.
  Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. American Thoracic Society and Infectious Diseases Society of America.