Evaluating the therapeutic benefit of bacterial lysates in chronic obstructive pulmonary disease: a systematic review and meta-analysis

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• Picked for Pulmonary and Respiratory Medicine (paper of the day, 7 November 2026): Systematic review of bacterial lysates for COPD exacerbation prevention

Abstract

BACKGROUND: Chronic obstructive pulmonary disease (COPD) with exacerbations often triggered by infections. Bacterial lysates have been investigated as interventions to reduce the exacerbations of COPD. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating bacterial lysates (BLs) in adults with chronic obstructive pulmonary disease (COPD). PubMed, EMBASE, CENTRAL, Web of Science, Google Scholar, ICTRP, and ClinicalTrials.gov were searched. In adults with COPD that compared bacterial lysates with placebo or conventional COPD therapy. Primary outcomes were the effect of BLs on exacerbations and duration. Secondary outcomes were hospitalisation risk, the mean number of exacerbations per participant during trial follow up, symptom scores for dyspnoea, sputum, cough, and adverse events. We used random-effects meta-analysis, assessed risk of bias with Cochrane RoB 2, graded certainty with GRADE. RESULTS: Fifteen RCTs were included. The pooled risk ratio (RR) for exacerbation in patients with COPD treated with BLs vs. control was 0.83 (95% CI 0.74-0.93; P = 0.0009). The mean difference (MD) for exacerbation duration showed no statistical significant reduction -9.26 Days (95% CI -19.56 to 1.03; P = 0.08). Mean number of exacerbations (MD) -0.19 (95% CI -0.30 to -0.08; P = 0.0009). Hospitalisation RR was 0.52 (95% CI 0.35-0.78; P = 0.001).Symptom outcomes were dyspnoea standardised mean difference (SMD) -0.42 (95% CI -0.75 to -0.10; P = 0.01), cough (SMD) -0.37 (95% CI -0.63 to -0.11; P = 0.006), while sputum production showed no significant change (SMD) -0.20 (95% CI -0.65 to 0.25; P = 0.39), The RR for adverse events was 0.95 (95% CI 0.86-1.04; P = 0.27). CONCLUSION: Bacterial lysates may be associated with lower COPD exacerbation and hospitalisation risk, with small numerical improvements in dyspnoea, cough, sputum production showed no significant improvement; effects varied by formulation, these findings require confirmation in formulation specific trials. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD42024570783, PROSPERO CRD42024570783.

Abstract as published, via PubMed.