No 2025 ATS Guideline on Pneumonia Exists
There is no published 2025 ATS guideline on pneumonia. The most recent comprehensive guideline is the 2019 ATS/IDSA guideline on community-acquired pneumonia 1. However, a controversial 2025 update was developed but IDSA withdrew its endorsement due to fundamental disagreements over antibiotic use in viral pneumonia 2, 3.
What Happened with the 2025 Update
The American Thoracic Society released a 2025 CAP guideline update that IDSA refused to endorse 3. The critical controversy centered on recommendations to prescribe antibiotics for patients with CAP who test positive for respiratory viruses—a recommendation that lacks supporting data and contradicts antimicrobial stewardship principles 2.
Key Points of Disagreement:
- The problematic recommendation: Use antibiotics in outpatients with comorbidities and inpatients with nonsevere CAP who test positive for respiratory viruses 3
- IDSA's position: Most patients with viral CAP do not have bacterial coinfections, and briefly withholding antibiotics in nonsevere illness to clarify diagnosis is safe 3
- The evidence gap: There is insufficient data supporting routine antibacterial therapy when respiratory viruses are detected 2
Current Standard: The 2019 ATS/IDSA Guideline
Use the 2019 ATS/IDSA guideline as your current evidence-based reference 1. This guideline uses the GRADE methodology and addresses 16 specific areas covering diagnostic testing, site of care determination, empiric antibiotic selection, and management decisions.
Core Principles from 2019:
- Focuses on immunocompetent adults in the United States
- Excludes recent foreign travelers and immunocompromised patients
- Targets major bacterial pathogens: S. pneumoniae, H. influenzae, M. pneumoniae, S. aureus, Legionella species, C. pneumoniae, and M. catarrhalis 1
Historical Context: The 2007 IDSA/ATS Guidelines
Prior to 2019, the 2007 IDSA/ATS consensus guidelines 4 provided the framework that many clinicians still reference:
Outpatient Treatment (2007):
- Previously healthy, no DRSP risk: Macrolide or doxycycline 4
- Comorbidities present: Respiratory fluoroquinolone OR β-lactam plus macrolide 4
- High macrolide resistance (≥25%): Use alternatives from the comorbidity category 4
Inpatient Non-ICU Treatment (2007):
- Respiratory fluoroquinolone alone OR β-lactam plus macrolide 4
- Preferred β-lactams: cefotaxime, ceftriaxone, ampicillin; ertapenem for selected patients 4
ICU Treatment (2007):
- Standard severe CAP: β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus azithromycin or fluoroquinolone 4
- Pseudomonas risk: Antipseudomonal β-lactam plus ciprofloxacin/levofloxacin OR antipseudomonal β-lactam plus aminoglycoside and azithromycin/fluoroquinolone 4
- CA-MRSA suspected: Add vancomycin or linezolid 4
Treatment Duration (2007):
- Minimum 5 days, afebrile for 48-72 hours, no more than 1 sign of clinical instability before stopping 4
Hospital-Acquired Pneumonia
For HAP/VAP/HCAP, the 2005 ATS guideline 5 remains relevant, emphasizing:
- Risk stratification for multidrug-resistant pathogens
- Hospital-specific antibiogram use
- Avoiding inadequate initial therapy (associated with increased mortality)
- Balancing appropriate coverage against excessive antibiotic use
Critical Caveat
Do not use the 2025 ATS update without IDSA endorsement. The guideline development process had significant methodological flaws 2, and the recommendation for antibiotics in viral CAP contradicts the principle of "first do no harm" 2. IDSA advocates for individualized, dynamic decision-making based on each patient's severity, clinical trajectory, and balance of features suggesting bacterial coinfection 3.
For current practice, rely on the 2019 ATS/IDSA guideline 1 and apply antimicrobial stewardship principles when viral pathogens are detected.