### Key points Severe community-acquired pneumonia (CAP) remains a frequent reason for admission to hospital. It is the most common cause of septic shock requiring escalation to treatment within an intensive care unit (ICU). Despite earlier recognition and recent advances in supportive care, severe CAP is still associated with substantial morbidity and mortality, more often seen in the elderly and those with considerable comorbidities. CAP is defined as an acute infection of the pulmonary parenchyma, with symptom onset in the community. Diagnosis can still be made within 48 h of hospital admission to meet criteria for a community-acquired infection. Severe CAP is defined as a pneumonia requiring supportive therapy within a critical care environment, that is associated with a higher mortality rate. Severe CAP is frequently a multisystem disease and patients will often present with multiple organ failure. The annual incidence of CAP is 1.6–10.6 per 1000 adult population in Europe.1 Between 1.2% and 10% of patients requiring hospital admission to treat CAP will require ICU admission. The incidence of CAP increases with age, and more than 90% of deaths related to severe pneumonia occur in patients over the age of 70. The 28 day mortality rate in patients admitted to critical care is ∼17%, which increases to 24.4% in those requiring invasive mechanical ventilation and 28.8% in those that develop septic shock.1 Mortality rates in younger patients are more influenced by the severity of the infection rather …