Influenza

Influenza, often called the flu, is an acute respiratory infection caused by influenza viruses, most commonly types A and B. It affects the nose, throat and lungs, and can range from a mild illness to a serious condition that may require hospitalization.

Common Symptoms

• Fever or feeling feverish with chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headache
• Fatigue
• Sometimes vomiting or diarrhea, more often in children

Not everyone with the flu has a fever. Symptoms usually begin suddenly.

Causes and How It Spreads
Influenza spreads mainly through respiratory droplets when an infected person coughs, sneezes or talks. You can also become infected by touching contaminated surfaces and then touching your mouth, nose or eyes. Symptoms usually appear one to four days after exposure.

Who Is at Higher Risk?

• Older adults, especially those over 65
• Young children, especially under five and particularly under two
• Pregnant individuals
• People living in long-term care facilities
• People with chronic conditions such as asthma, heart disease, diabetes, chronic lung disease, kidney or liver disease, weakened immune systems or severe obesity
• People with neurological or developmental conditions

Possible Complications
Influenza can lead to viral pneumonia, bacterial pneumonia, worsening of chronic conditions, dehydration and, rarely, inflammation of the brain or heart. People at higher risk are more likely to need hospital care or experience serious complications.

How Influenza Is Diagnosed
Diagnosis is often based on symptoms and the time of year. In some cases, rapid flu tests or more sensitive molecular tests (PCR) may be used, especially for high-risk patients, hospitalized individuals, during outbreaks or when results will guide treatment.

When to Seek Care
Seek medical care promptly if you are in a high-risk group or have severe or worsening symptoms such as difficulty breathing, chest pain, persistent high fever, confusion, severe weakness or signs of dehydration. Starting treatment within 48 hours can shorten illness and reduce complications, though some patients may benefit even if treatment begins later.

Prevention
The best protection against influenza is a yearly flu vaccine, recommended for most people age six months and older. Other preventive steps include frequent handwashing, covering coughs and sneezes, staying home when sick, avoiding close contact with ill individuals and following public health guidance. In some high-risk situations, antiviral medication may be used to help prevent illness.

How is the flu different from a common cold?
The flu usually starts suddenly and causes more intense symptoms such as high fever, body aches and extreme fatigue. Colds tend to cause milder symptoms like sneezing and congestion, with less frequent fever or muscle pain.

When should I see a doctor for flu-like symptoms?
Seek care if you are in a high-risk group or if symptoms are severe or worsen quickly, including trouble breathing, chest pain, confusion, fever that does not improve or inability to keep fluids down.

Are antiviral medicines important and who should get them?
Antiviral medicines can shorten illness and reduce complications, especially when started within 48 hours. They are recommended for hospitalized patients, those with severe symptoms and people at higher risk. Your clinician can help decide if they are appropriate.

Is the flu vaccine safe, and who should get it?
The flu vaccine is safe and recommended each year for most people age six months and older. It lowers the risk of severe illness, hospitalization and death. Talk with your provider if you have a history of severe vaccine allergies.

Can antibiotics treat the flu?
No. Antibiotics do not treat influenza because it is caused by a virus. They are only used if there is a bacterial infection, such as bacterial pneumonia.

How long am I contagious?
Adults are usually contagious from about one day before symptoms begin to five to seven days after becoming sick. Children and people with weakened immune systems may spread the virus longer.

How long does the flu usually last?
Most people recover within a few days to two weeks, though cough and fatigue may last longer.

What can I do at home to feel better?
Rest and stay hydrated
Use fever and pain relievers as directed
Try a humidifier or saline nasal spray
Monitor symptoms closely
Avoid contact with others to prevent spread

Can I get the flu vaccine if I already have flu symptoms?
If you have moderate or severe illness, wait until you recover before vaccination. With mild symptoms and no fever, vaccination is often still possible. Ask your provider for guidance.

Can pregnant people receive the flu vaccine?
Yes. The flu vaccine is recommended during any trimester and helps protect both the pregnant person and the baby.

When should children return to school or daycare after the flu?
Children can usually return after being fever-free for at least 24 hours without fever-reducing medication and when they feel well enough to participate. Follow local guidance.

If I test negative on a rapid flu test but still have symptoms, what should I do?
Rapid tests can miss infections. If symptoms and risk factors suggest influenza, your provider may order further testing or begin treatment based on clinical judgment. Contact TidalHealth for guidance.