New clinical guidance on the diagnosis and management of community-acquired pneumonia

---

Reference: April 2026 | Issue 4 | Vol 12 | Page 39

---

At the end of 2025, the American Thoracic Society (ATS) published new guidance on the diagnosis and management of community-acquired pneumonia (CAP). This is the first revision of the guideline since the previous recommendations were published in 2019.

This new iteration recognises advances in recent years, including the availability of rapid molecular tests for multiple pathogens, along with emerging imaging technology and new evidence surrounding the host response and the potential role of corticosteroids.

The new guidance is not a complete revision of the 2019 recommendations. Instead, the 2025 update addresses four specific clinically questions.

1. Should lung ultrasound be considered a reasonable alternative to chest radiography for diagnosis in adults with suspected CAP?

2. Should adults with CAP who have a positive test result for a respiratory virus be treated with empiric antibacterial therapy?

3. Should adults with CAP who reach clinical stability be treated with less than five days of antibiotics?

4. Should adults who are hospitalised with CAP be treated with corticosteroids?

These areas were selected by the committee because of their clinical relevance and the potential influence of recent literature on the existing standard of care.

Recommendations

Regarding lung ultrasound (LUS), 13 (87%) of 15 committee members voted in favour of the following conditional recommendation: For adults with suspected CAP, lung ultrasound is an acceptable diagnostic alternative to chest radiography in medical centres where appropriate clinical expertise exists.

For adult outpatients without comorbidities who have clinical and imaging evidence of CAP and who have a positive test result for a respiratory virus, it is recommended not to prescribe empiric antibiotics.

Although 93 per cent of committee members voted in favour of this recommendation, the guideline noted that the evidence was of very low quality. This is a conditional recommendation as the balance between benefit and harm of empiric antibiotics varies according to clinical context.

For adult outpatients with comorbidities who have clinical and imaging evidence of CAP and who have a positive test result for a respiratory virus, empiric antibiotics are recommended because of concern for bacterial-viral coinfection. Again, this is a conditional recommendation because the balance between benefit and harm varies based on the clinical context.

More than 50 per cent of the guideline committee members agreed that the following comorbidities may warrant antibiotic therapy for outpatients with CAP and a respiratory virus:

• Chronic pulmonary disease other than asthma
• End-stage liver disease
• End-stage renal disease
• Cardiovascular disease
• Alcoholism
• Neoplastic disease.

There was less than 50 per cent agreement that the following comorbidities may warrant antibiotic therapy for outpatients with CAP
and a respiratory virus:

• Neurological disease
• Chronic liver disease
• Malnutrition
• Current smoker
• Corticosteroid therapy (<20mg daily for <4 weeks)
• Diabetes mellitus
• Chronic kidney disease
• HIV (CD4 >200)
• Asthma
• Rheumatological diseases (not receiving immunosuppressants) 
• Obesity (BMI >30kg/m²).

The guidance also states that, for adult inpatients with clinical and imaging evidence of non-severe CAP who test positive for a respiratory virus, the risk of bacterial-viral coinfection warrants empiric antibiotics.

For adult inpatients with clinical and imaging evidence of severe CAP who have a positive test result for a respiratory virus, empiric antibiotics are recommended because of concerns for bacterial-viral coinfection.

Although the committee was unanimous in making this decision, the recommendation is conditional because of the absence of comparative evidence.

Regarding the duration of antibiotic treatment for CAP, it is recommended that for adult outpatients with CAP who reach clinical stability, duration should be less than five days (minimum three days) rather than five or more days. The same duration is recommended for adult inpatients with non-severe CAP who reach clinical stability.

This is a conditional recommendation that requires individualisation. The guidance includes a list of factors that weaken this recommendation.

For adult inpatients with severe CAP who reach clinical stability, the recommendation is five or more days of antibiotics. This recommendation is strong, despite the low quality of evidence, because insufficient antibiotic therapy can result in serious adverse outcomes or death in patients with severe CAP.

The guidance advises that recommendations on treatment duration are condition and require individualisation. Included in the guidance is a list of factors that weaken this recommendation.

Systemic corticosteroids are not recommended for adult inpatients with non-severe CAP. This is a strong recommendation with unanimous support, although the overall quality of evidence was low. The intent is to avoid harmful side effects, such as hyperglycaemia, for which there is robust evidence.

For adult inpatients with severe CAP, systemic corticosteroids are recommended. This recommendation is conditional due to the low quality of evidence. This recommendation does not apply to patients with severe CAP caused by influenza pneumonia.

Summary

The new ATS guidance draws on new evidence to update the 2019 guideline on the diagnosis and management of CAP. The 2026 update regards the use of LUS as equivalent to chest radiography, provided there is sufficient clinical expertise and infrastructure available.

Concerning the use of antibacterial therapy for patients diagnosed with a respiratory virus, the suggestion is to withhold antibacterial therapy only in outpatients who do not have coexisting medical conditions that put them at risk of severe outcomes.

Addressing the optimal duration of antibiotic therapy, five days of treatment is regarded as acceptable (minimum of three-day duration), except in cases of severe CAP or pneumonia caused by necrotising or resistant organisms, such as S aureus or P aeruginosa. The use of systemic corticosteroids is endorsed solely for a subgroup of patients experiencing severe CAP without influenza virus infection.

However, it must be noted that most of the recommendations presented are based on low-quality evidence or have low or very low certainty of effects. Hence, the guideline committee stressed the need for new studies.

“We encourage research efforts to improve the evidence surrounding pneumonia care, particularly by conducting studies that evaluate patient-oriented outcomes in the areas of diagnosis, individualised antimicrobial treatment and host-directed therapies, and also to evaluate the relationship between CAP management of individual patients and public health outcomes, such as antimicrobial resistance and infection transmission,” the guideline authors said.

“Given the potential impact of future research on our current recommendations, it is crucial for physicians to thoroughly assess patients when implementing a clinical approach on the basis of these recommendations and to individualise their management according to patients’ risks and clinical responses. We encourage a nuanced clinical approach to pneumonia care that acknowledges the complexity of lung disease and uncertainty in the evidence base.”