In this study, the RBD-VLP antigen was formulated with two adjuvants: (i) aluminum hydroxide (alum) and (ii) alum combined with CpG 1018—a potent Toll-like receptor 9–agonizing adjuvant known to elicit T helper cell 1 (TH1)–like responses (31) and used in the commercial hepatitis B vaccine, HEPLISAV-B. This evidence concerns the gene TLR9 and hepatitis B virus infection.