This was supported when controlled comparisons were made in murine vaccination models, finding that LAIV was capable of generating influenza-specific CD4+ and CD8+ Trm that facilitated cross-strain protection, while the injectable inactivated vaccine did not generate Trm nor facilitate cross-strain protection, highlighting the potential importance of route of immunization in eliciting T cells resident to the respiratory tract (10). The gene discussed is CD4; the disease is influenza.