Tuberculosis (TB) is a significant global health burden. BCG, the only licenced anti-TB vaccine, provides variable protection against TB but can also provide heterologous benefits. Trained immunity has been implicated in mediating the heterologous effects of BCG and protection against mycobacterial infections; however, factors mediating these effects have not been fully explored. To examine the innate immune factors with a possible role in the protection against TB and non-mycobacterial infections, this study investigated innate immune responses to BCG and other agents using samples available from healthy adult donors and 2 BCG-vaccinated infant cohorts from the UK and South Africa (SA). An in vitro system for human CD14+ monocyte training with BCG was independently investigated to screen for markers associated with trained immunity and protection against TB. A weaker effect of training on IL-6 and TNFα production upon secondary stimulation was observed compared to previous studies, the extent of which was associated with dose and viability of BCG. Differences in heterologous and mycobacteria-specific effects of BCG have been observed in different populations, so CD14+ monocyte responses to BCG and toll-like receptor agonists were studied by flow cytometry in PBMCs from UK and SA infants and their gene expression, cytokine profiles and mycobacterial growth inhibition analysed. Although the two cohorts differed, these agents induced similar patterns of innate responses. Previous studies suggested that trained immunity can contribute to protection against TB, therefore cytokine profiles of whole blood cultures stimulated with BCG or TB vaccine candidates were analysed. Distinct cytokine profiles were detected, predominantly driven by vaccine antigen carriers. A spore-based fusion protein vaccine induced the strongest production of G-CSF, GM-CSF, IL-1β, IL-6 and TNFα, suggesting that TB vaccine candidates may contribute to antimycobacterial protection via trained immunity and that cytokine profiling can be an effective tool to screen for candidates that may have such properties. To conclude, this study found some heterologous effects of BCG in vitro; similar innate cytokine response patterns in two BCG-vaccinated infant cohorts and suggested that other TB vaccines may also have heterologous effects.