Community-acquired pneumonia (CAP) is a common and potentially serious illness with a significant morbidity and mortality rate. The estimated annual incidence of CAP is five to 11 cases per 1000 adults and incidence increases with age and seems to be higher in men than in women. CAP remains one of the most common medical causes of hospital admission in healthcare systems and in Portugal, between 2000 - 2009, it was responsible for 3.7% of the hospitalizations.

After diagnosis, the initial management decision is to determine the location of care: outpatient, hospitalization, or admission to an Intensive Care Unit (ICU). It is essential to avoid unnecessary admissions to avoid the costs and higher consumption of resources and minimize the risk of nosocomial infections by resistant hospital bacteria or thromboembolic events.

The aim of this study was to determine the incidence of CAP in a Portuguese adult outpatient population (over 18 years old) and to characterize those patients, their risk factors and respective vaccination status (seasonal flu and pneumococcal vaccination).