Awareness
Flu season often brings familiar symptoms such as fever, fatigue, body aches, and a general feeling of being run down.
For most people, recovery happens with rest and supportive care.
In some cases, however, influenza (flu) can increase the risk of developing pneumonia – a far more serious lung infection. Recognising when symptoms shift from mild illness to medical emergency is critical.
Flu vs pneumonia: what’s actually happening in your body?
Influenza is a virus that infects the nose, throat, and airways, and it usually starts suddenly. Common symptoms include fever, chills, body aches, headache, tiredness, sore throat, dry cough, and a blocked or runny nose.
“People often feel extremely weak and run down, but breathing may initially remain relatively normal,” explains Christiaan Kilian, Operational Advanced Life Support Paramedic (ALS) at ER24 Pretoria.
Pneumonia is an infection in the lungs that directly affects oxygen exchange. It is generally more severe and impacts breathing.
“Symptoms of pneumonia commonly include shortness of breath, rapid or laboured breathing, chest pain when breathing or coughing, persistent cough with mucus, low oxygen levels, and confusion, particularly in older patients,” he says. “Pneumonia generally causes more severe breathing problems compared to flu.”
When flu turns into pneumonia
Flu can increase the risk of pneumonia when the infection weakens the respiratory tract and damages the body’s natural defences. This allows the Influenza virus, bacteria or other viral infections to take hold in the lungs.
“This can lead to viral pneumonia caused directly by influenza, or secondary bacterial pneumonia developing afterwards,” says Kilian.
A concerning pattern is a brief improvement in flu symptoms followed by sudden worsening, including fever returning, increasing cough, chest pain, or difficulty breathing.
This happens because the initial viral infection can suppress immune response, allowing a secondary infection to develop once symptoms temporarily appear to improve.
Warning signs that need urgent medical attention
- Rapid or laboured breathing
- Chest pain
- Severe dehydration
- Persistent high fever
- Confusion or unusual drowsiness
- Collapse or fainting
- Coughing blood
- Signs of low oxygen levels, which include:
- Increasing shortness of breath
- Difficulty speaking in full sentences
- Unusual fatigue
- Confusion
- Bluish lips or fingertips.
“In children, warning signs include grunting while breathing, chest retractions, poor feeding, lethargy, fewer wet nappies, and seizures,” says Kilian.
Who is most at risk?
People in these groups are more likely to develop severe complications:
- Older adults (aged 65 and over)
- Infants and young children
- Pregnant women
- People with asthma or chronic lung disease
- Heart disease patients
- Diabetics
- Immunocompromised patients
- Cancer patients
- Smokers
- People living with obesity.
“These patients are at higher risk of severe pneumonia, respiratory failure, or sepsis,” says Kilian.
Don’t wait too long to get medical help
People who put off seeing a doctor are at greater risk of complications. Other common mistakes include:
- Ignoring worsening breathing problems
- Staying physically active when ill instead of resting
- Drinking too little fluid
- Taking leftover antibiotics without medical advice
- Stopping prescribed medication too soon
- Assuming severe symptoms are “just flu”
- Failing to monitor vulnerable people closely.
Reduce your risk during flu season
You can lower your risk of getting flu or developing complications like pneumonia by taking some simple steps:
- Get a flu shot every year
- Get a pneumonia vaccine if you’re eligible
- Wash your hands regularly
- Avoid close contact with people who are sick
- Stay at home when you’re unwell
- Wear a mask in high-risk healthcare settings if you’re vulnerable
- Get enough sleep and eat well
- Keep long-term health conditions under control
- Avoid smoking and vaping
- Take prescribed medication for chronic conditions as directed.
Flu and pneumonia can start with similar symptoms, but they don’t always develop in the same way. The important thing is to watch for any changes, especially if breathing becomes difficult.
“When in doubt, early medical assessment is always safer than waiting for symptoms to worsen,” Kilian advises.