Treatment according to current guidelines. Often a 7 day course of antibiotics. Initial treatment should be broad spectrum antibiotics and can be narrowed down if a specific pathogen is identified.

Treatment according to CRP levels. Patients will be started on broad spectrum antibiotics for at least 3 days, treatment can be switched to small-spectrum antibiotics if a specific pathogen is identified. From day 4 to 7 daily blood tests will be performed in order to evaluate whether or not treatment can be discontinued. If treatment is discontinued, no more blood tests will be performed.

Treatment according to PCT levels. Patients will be started on broad spectrum antibiotics for at least 3 days, treatment can be switched to small-spectrum antibiotics if a specific pathogen is identified. From day 4 to 7 daily blood tests will be performed in order to evaluate whether or not treatment can be discontinued. If treatment is discontinued, no more blood tests will be performed.

The cutoff point is a CRP below 100 mg/L and a reduction to 50% of the initial value.

Cure - resolution or improvement of symptoms and clinical signs related to pneumonia without the need for additional or alternative antibiotic therapy

Failure - persistence or progression of all signs and symptoms of the acute process after randomisation or the development of a new pulmonary or extrapulmonary respiratory tract infection, or the progression of abnormalities on chest radiograph after randomisation, or death due to pneumonia, or the inability to complete the study owing to adverse events

Indeterminate - patient receives less than 80% of the study drug for reasons other than clinical failure, a concomitant infection outside the respiratory tract requiring antibiotic treatment, lost to follow-up, or death unrelated to the primary diagnosis.