How the Flu Spreads
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How Is the Flu Spread? Virus Transmission Explained

21 Dec 2023

While anyone can catch the flu any season of the year, winter and fall are the most common time for the influenza virus to spread, giving us "flu season." There are a number of factors that play into how you can contract it, and fortunately there are also many strategies you can take to prevent the flu including getting the flu vaccine. Make sure you are ready when flu season starts and before symptoms develop.

How Do People Get the Flu?

Airborne Transmission: The flu virus can be transmitted through respiratory droplets when an infected person coughs, sneezes or talks. If someone nearby inhales these droplets, they can become infected.

Direct Contact: You can get the flu by touching a surface or object contaminated with the virus and then touching your mouth, nose or eyes. The flu virus can survive on surfaces for a period of time.

Indirect Contact: Sharing personal items like eating utensils, glasses or towels with an infected person can also lead to transmission.

Close Contact: Being in close proximity to someone who has the flu, especially in enclosed spaces like classrooms, offices or public transportation, can increase the risk of infection.

Contact with Contaminated Surfaces: Flu viruses can survive on surfaces for several hours, and touching a contaminated surface followed by touching your face can introduce the virus into your body.

Asymptomatic Carriers: Some individuals infected with the flu virus may not show symptoms but can still spread the virus to others. This makes it challenging to identify and contain outbreaks.

Large Crowds: Crowded places where people are in close proximity, such as concerts or sporting events, can facilitate the spread of the virus.

Travel: Traveling to regions with ongoing flu outbreaks can increase the risk of exposure to the virus.

When are People with the Flu Contagious?

An infected person with the flu virus can spread it to others 1 to 2 days before they start feeling sick or before symptoms develop. This is part of the reason why the flu spreads rapidly; people may not even know they are infected.

People with the flu virus are most contagious during the first 3-4 days after their illness begins. However, they can continue to spread the influenza virus for up to 7 days after symptoms start, especially in children and people with weakened immune systems.

Children, especially those younger than 5 years old, can be contagious for a longer period, sometimes for up to 7 days before symptoms appear and for up to 10 days or more after becoming sick.

What are Common Flu Symptoms?

The flu can manifest in a diverse set of symptoms, sometimes making it a challenging illness to identify solely based on its presentation. The hallmark symptoms of influenza often include:

  • Fever: This is often one of the first signs of the flu and can range from low-grade to high.
  • Cough: A persistent flu cough is a common symptom; it’s often dry or hacking.
  • Sore Throat: A scratchy or sore throat is common and can be one of the early symptoms.
  • Stuffy or Runny Nose: The sick person may experience nasal congestion, sneezing, and a runny nose.
  • Headache: Headaches, sometimes severe, are common with the influenza virus.
  • Fatigue: The infected person may feel extremely tired or fatigued and it may last for several weeks.
  • Muscle and Body Aches: Muscle pain and body aches are common, and they can be quite severe.
  • Chills and Sweats: Feeling chilled, even if you have a fever, is common. Sweating may follow the chill.
  • Weakness: Generalized weakness and lack of energy are typical.
  • Nausea and Vomiting: Some people with the flu experience nausea and vomiting, though this is more common in children than adults.

Protecting Yourself and Others from Virus Transmission

How the Flu Spreads


Protecting yourself and others from virus transmission including a highly contagious respiratory illness like the flu involves adopting a combination of preventive measures, especially if you are around people with weakened immune systems.

Getting the annual flu vaccine is one of the most effective ways to safeguard yourself and those around you against influenza.

Practice good hand hygiene by washing your hands frequently with soap and water for at least 20 seconds. This is particularly crucial after visiting public places, touching your face, or after coughing or sneezing. When soap and water are unavailable, use hand sanitizer containing at least 60% alcohol.

In areas where the flu virus is spreading or as recommended by health authorities, wearing a mask that covers your nose and mouth is essential. This is especially important in indoor public settings or situations where maintaining a safe physical distance is challenging.

Maintain physical distancing by keeping a distance of at least 6 feet from individuals who are not part of your household, particularly in crowded or indoor environments.

Refrain from touching your face, specifically your eyes, nose, and mouth, with unwashed hands, as this can introduce the virus into your body.

Practice respiratory hygiene by covering your mouth and nose with a tissue or your elbow when you cough or sneeze. Dispose of used tissues in a lined trash can and wash your hands immediately.

Regularly clean and disinfect frequently-touched surfaces in your home, workplace, and public spaces to reduce the risk of virus transmission. By adopting these measures, you can significantly contribute to minimizing the spread of the flu virus and protecting the health of both yourself and your community.

Symptom Relief For If You Do Catch the Flu

Rest: Give your body the rest it needs to recover. Stay home from work or school, and avoid strenuous activities until you're feeling better.

Keep Hydrated: Drink plenty of fluids including water, herbal teas, and clear broths. Staying hydrated helps alleviate symptoms like fever and prevents dehydration.

Hot Showers or Steam: Breathing in steam from a hot shower or bowl of hot water can help relieve congestion.

Proper Nutrition: Eat a balanced diet with plenty of fruits, vegetables, and lean proteins to support your immune system.

Follow Healthcare Advice: If your symptoms worsen or if you are in a high-risk group (such as young children, the elderly, pregnant women or those with underlying health conditions), contact a healthcare provider. They can provide guidance and may prescribe antiviral medications in some cases.

Restorative Sleep: Ensure you get enough sleep, as restorative sleep is essential for recovery.

Over-the-Counter Medications for the Flu

There’s a handful of options when it comes to over-the-counter (OTC) medications available to alleviate the symptoms associated with the flu. These medications aim to provide relief from the discomfort that often accompanies the influenza virus, such as fever, body aches, congestion, and coughing. Common OTC options include:

Always follow the dosing instructions on the medication labels and seek medical treatment if symptoms worsen or if you have questions or concerns.

It's important to remember that most people with the flu recover at home without the need to seek medical treatment. Mucinex® products are designed to help alleviate the most common flu symptoms. However, if you experience severe symptoms such as difficulty breathing, chest pain, confusion, persistent high fever or bluish lips or face, seek immediate medical attention.

  1. Centers for Disease Control and Prevention (2022), Flu Season
  2. Centers for Disease Control and Prevention (2022), Prevent Seasonal Flu
  3. American Red Cross (2023), Flu Safety

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