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Introduction Vaccines are powerful tools for controlling microbial infections and preventing epidemics. To enhance the immune response to antigens, effective subunit vaccines or mRNA vaccines often require the combination of adjuvants or delivery carriers. In recent years, with the rapid development of immune mechanism research and nanotechnology, various studies based on the optimization of traditional adjuvants or various novel carriers have been intensified, and the construction of vaccine adjuvant delivery systems (VADS) with both adjuvant activity and antigen delivery has become more and more important in vaccine research. Areas covered This paper reviews the common types of vaccine adjuvant delivery carriers, classifies the VADS according to their basic carrier types, introduces the current research status and future development trend, and emphasizes the important role of VADS in novel vaccine research. Expert opinion As the number of vaccine types increases, conventional aluminum adjuvants show limitations in effectively stimulating cellular immune responses, limiting their use in therapeutic vaccines for intracellular infections or tumors. In contrast, the use of conventional adjuvants as VADS to carry immunostimulatory molecules or deliver antigens can greatly enhance the immune boosting effect of classical adjuvants. A comprehensive understanding of the various delivery vehicles will further facilitate the development of vaccine adjuvant research.

The Varicella zoster virus (VZV), responsible for both varicella (chickenpox) and herpes zoster (shingles), presents significant global health challenges. While primary VZV infection primarily affects children, leading to chickenpox, reactivation in later life can result in herpes zoster and associated post-herpetic neuralgia, among other complications. Vaccination remains the most effective strategy for VZV prevention, with current vaccines largely based on the attenuated vOka strains. Although these vaccines are generally effective, they can induce varicella-like rashes and have sparked concerns regarding cell virulence. As a safer alternative, subunit vaccines circumvent these issues. In this study, we developed a nanoparticle-based vaccine displaying the glycoprotein E (gE) on ferritin particles using the SpyCatcher/SpyTag system, termed FR-gE. This FR-gE nanoparticle antigen elicited substantial gE-specific binding and VZV-neutralizing antibody responses in BALB/c and C57BL/6 mice—responses that were up to 3.2-fold greater than those elicited by the subunit gE while formulated with FH002C, aluminum hydroxide, or a liposome-based XUA01 adjuvant. Antibody subclass analysis revealed that FR-gE produced comparable levels of IgG1 and significantly higher levels of IgG2a compared to subunit gE, indicating a Th1-biased immune response. Notably, XUA01-adjuvanted FR-gE induced a significant increase in neutralizing antibody response compared to the live attenuated varicella vaccine and recombinant vaccine, Shingrix. Furthermore, ELISPOT assays demonstrated that immunization with FR-gE/XUA01 generated IFN-γ and IL-2 levels comparable to those induced by Shingrix. These findings underscore the potential of FR-gE as a promising immunogen for the development of varicella and herpes zoster vaccines.