Synthetic unmethylated CpG oligonucleotides (CpG-ODN) are potent Toll-like receptor-9 (TLR-9) agonists that have strong adjuvant properties (Kayraklioglu et al., 2021) and have been shown to increase the efficacy of an influenza vaccine administered IN (Tateishi et al., 2019). The gene discussed is TLR9; the disease is influenza.