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What Makes the Flu So Deadly?

Most people don’t think of the flu as deadly.


Because they have likely had the flu and didn’t die…

What Makes the Flu So Deadly?

Still, the flu can be deadly and although some folks are more at risk for dying from the flu than others, even otherwise healthy children and adults can die with the flu.


It surely doesn’t help that even after a natural infection, we don’t build up immunity to protect us from flu viruses in subsequent years. Or that even though the flu vaccine isn’t as effective as we would like, many people don’t get vaccinated and protected.

Mostly, the flu is deadly because it can lead to severe symptoms in many people, even otherwise healthy people.

Although most people associate the flu with a fever, runny nose, cough, and body aches, the flu virus can rarely cause a primary viral pneumonia. Even when it doesn’t, an influenza infection can make it harder to breath. The flu virus can also cause severe bronchiolitis, like RSV does, croup, and can trigger asthma attacks.

Other severe complications that can be deadly include:

  • bacterial superinfections
  • myocarditis (inflammation of the heart) and pericarditis
  • congestive heart failure
  • encephalitis (inflammation of the brain)
  • myositis (inflammation of our muscles)
  • toxic shock syndrome
  • multi-organ failure

More rarely, the flu can cause Guillain-Barrésyndrome and Reye syndrome (associated with taking aspirin).

“Most people who get flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of flu, some of which can be life-threatening and result in death.”

CDC on Flu Symptoms & Complications

But why do some people develop these flu complications and die, while others don’t?

That’s the real question most people want answered, not what the flu does to our body and how the flu virus attaches to and enters our cells, replicates, destroys our cells, triggers an immune response, and causes symptoms.

If you must know, you can likely blame it on a combination of the virulence factors of the flu virus strain and host factors of the person who is infected, but mostly, it’s because the flu can be a deadly disease.

That’s when you get worsening flu symptoms and signs, which might include trouble breathing, chest pain, dehydration, irritability, lethargy, confusion, or persistent vomiting, etc.

185 children died with the flu during the 2017-18 flu season.
185 children died with the flu during the 2017-18 flu season.

And because this can happen to almost anyone, unless they have a true contraindication, everyone should get vaccinated and protected against the flu.

More on Flu Deaths

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