Community-Acquired Pneumonia in Adults: Rapid Evidence Review

Community-acquired pneumonia (CAP) is a common condition with a hospitalization rate of about 2% in people 65 years or older and is associated with a 30-day mortality rate of 6% in hospitalized patients. In studies conducted before the COVID-19 pandemic, a bacterial pathogen was identified in 11% of patients, a viral pathogen in 23% of patients, and no organism in 62% of patients. Certain signs and symptoms can be helpful in diagnosing CAP and selecting imaging studies. Diagnosis is usually made with a combination of history, physical examination, and findings on chest radiography, lung ultrasonography, or computed tomography. Procalcitonin measurement is not recommended. CRB-65 (confusion, respiratory rate, blood pressure, 65 years of age) is a well-validated risk stratification tool in the primary care setting and does not require laboratory testing. For outpatients without comorbidities, treatment with amoxicillin, doxycycline, or a macrolide is recommended (the latter only in areas where pneumococcal resistance to macrolides is less than 25%). In outpatients with comorbidities and inpatients with nonsevere pneumonia, a combination of a beta-lactam or third-generation cephalosporin plus a macrolide, or monotherapy with a respiratory fluoroquinolone is recommended. Patients should be treated for methicillin-resistant Staphylococcus aureus or Pseudomonas infection only if they present with risk factors for those pathogens. All adults 65 years or older or those 19 to 64 with underlying conditions should receive the 20-valent pneumococcal conjugate vaccine alone or the 15-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal polysaccharide vaccine one year later. The 13-valent pneumococcal conjugate vaccine is no longer recommended for routine administration. The Centers for Disease Control and Prevention recommends vaccination against influenza and SARS-CoV-2 viruses for all adults.