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World Pneumonia Day!

What is Pneumonia?

Pneumonia is an infection of the lungs especially affecting the alveoli that fill with pus and fluid instead of air. (alveoli are tiny air sacs that help to deliver oxygen from the air to the blood).

Based on where it was acquired, pneumonia is characterized as:

  • Community-Acquired Pneumonia (CAP)
    • Responsible for the highest rates of morbidity and  mortality from infection among adults in Europe.1
    • Largest cause of death from infection  among children worldwide.2
    • In the EU, CAP is responsible for 1 million hospital admissions every year1
  • Nosocomial pneumonia
    • Presents 48 hours after admission, Hospital Acquired Pneumonia –HAP
    • Presents 48-72 hours after intubation, Ventilator Acquired Pneumonia-VAP acquired1


The most common cause of CAP, is streptococcus pneumoniae (pneumococcus), although other bacteria, viruses or fungi can also infect the lungs.3

“Atypical pneumonia” refers to pneumonia specifically caused by chlamydia, legionella, mycoplasma or psittacosis due to the different clinical presentation and the fact that it requires different treatment.3

“Aspiration pneumonia” refers to the infection that occurs as a result of the inhalation of solid or liquid into the lungs (food, vomit, saliva, chemicals etc.). It is important to identify aspiration pneumonia as the treatment approach is different.

Risk factors for aspiration are:

  • Any conditions that:
    • Alter the swallowing function (brain injuries, strokes, neurological diseases)
    • Alter the level of consciousness (drugs, alcohol abuse)
  • Older age
  • Drowning
  • Rarely, complications of medical procedures

How is it Spread?

Pneumonia is usually spread through droplets in the air released by coughing and/or sneezing. In young children, virus and bacteria commonly found in their noses or throat can potentially be inhaled and infect the lungs. It can also reach the lung via blood from other sites of infection.

Risk factors

  • Age (young children and adults >65 years old)
  • Presence of chronic conditions such as COPD, heart disease, or diabetes
  • The time period immediately following a viral infection such as flu
  • Smoking
  • Alcohol and/or substance abuse
  • Residing in crowded areas (for example shelters, residential care facilities or army bases)


Symptoms of pneumonia last 3 to 4 weeks while activities of daily living may be impaired for longer.

The presence of a cough and at least one of the following characterize pneumonia:

  • Fever (higher than 38 oC) that persists for more than 4 days
  • Fatigue
  • Chest pain when when taking a deep breath
  • Trouble breathing or quickened breathing
  • A fast heartbeat
  • Shaking and chills
  • Nausea, vomit or diarrhea


Diagnosis is based on the symptoms and chest radiography findings. Microbiology testing to identify the microorganism and other more complex advanced tests are only needed in special circumstances (for example in severe disease or immunocompromised patient).


In most cases, pneumonia can be successfully treated with broad spectrum antibiotics that target the most likely and frequent causes without the need for more complex interventional tests that are only performed when indicated. It is important that treatment is started as soon as possible. Follow-up with  physician is recommended until both symptoms and radiologic findings return to normal.


The most important means for prevention of pneumonia are:

  • Seasonal influenza vaccination
  • Pneumococcal vaccination
  • Smoking cessation
  • Frequent hand washing
  • Good general hygiene
  • Exclusive breastfeeding
  • Healthy diet and nutrition
  • Good management of chronic illnesses


  1. European Respiratory Society. Pneumonia – ERS.
  2. World Health Organization. Pneumonia. Published 2016.
  3. US Center for Disease Control. Pneumonia | Home | CDC. Published 2018.

Read the Pneumonia Fact Sheet in Greek here.