Pneumococcal conjugate vaccines (PCVs) are widely used, to prevent infections caused, by Streptococcus pneumoniae, but evidence shows that they also exert clinically relevant nonspecific effects. This review summarizes current data on the impact of PCVs on non-pneumococcal respiratory infections and. outlines possible underlying mechanisms. We analyzed. studies published between 2011 and 2025 describing clinical outcomes, immunological responses, and. molecular pathways associated with PCV use. PCVs were found to reduce influenza-related hospitalizations, respiratory syncytial virus infections, and. non-pneumococcal pneumonia. These effects may result from reduced pneumococcal carriage, modulation of respiratory microbiota, and trained innate immunity. Further research is required, to clarify populationlevel implications of next-generation PCVs.