IL18 and respiratory syncytial virus infectious disease: Vaccination leads to IFNγ induction, which is the most important cytokine for a cellular immune response, further confirmed by increased levels of (i) CCR5, a chemokine receptor expressed on Th1 cells which plays an important role in the CD8+ T cell early memory response [26]; (ii) CXCL10, that mediates immunity to respiratory syncytial virus infection by augmenting dendritic cell and CD8+ T cell efficacy [27]; and (iii) IL-18, a pro-inflammatory cytokine inducing IFNγ production.