 The BCG vaccine, widely used worldwide for tuberculosis protection, has non-specific immunomodulatory effects on homoal responses to other vaccines. A systematic review found five out of eight studies reporting a beneficial effect of BCG on vaccine responses, with higher antibody levels observed in the BCG-vaccinated group against hepatitis B, polio type 1, pneumococcus, and influenza. However, no study reported a statistically significant increase in response to other vaccines. Future studies should focus on the influence of BCG vaccine strain and timing of administration to improve vaccine efficacy and duration of protection. This article was authored by Petra Zimmerman and Nigel Curtis.