An Overview of Vaccine Adjuvants: Current Evidence and Future Perspectives

Abstract

Vaccinations are one of the most important preventive tools against infectious diseases. Over time, many different types of vaccines have been developed concerning the antigen component. Adjuvants are essential elements that increase the efficacy of vaccination practises through many different actions, especially acting as carriers, depots, and stimulators of immune responses. For many years, few adjuvants have been included in vaccines, with aluminium salts being the most commonly used adjuvant. However, recent research has focused its attention on many different new compounds with effective adjuvant properties and improved safety. Modern technologies such as nanotechnologies and molecular biology have forcefully entered the production processes of both antigen and adjuvant components, thereby improving vaccine efficacy. Microparticles, emulsions, and immune stimulators are currently in the spotlight for their huge potential in vaccine production. Although studies have reported some potential side effects of vaccine adjuvants such as the recently recognised ASIA syndrome, the huge worth of vaccines remains unquestionable. Indeed, the recent COVID-19 pandemic has highlighted the importance of vaccines, especially in regard to managing future potential pandemics. In this field, research into adjuvants could play a leading role in the production of increasingly effective vaccines.

Colloidal Polyelectrolyte Complexes from Hyaluronic Acid: Preparation and Biomedical Applications

“…Particularly, while the works above concern only peptide or protein vaccine delivery, HA‐based colloidal PECs have also demonstrated their capacity to deliver different types of RNA and therefore can be studied for RNA‐based vaccines, which are emerging as a new vaccine generation. [ 193 ] Those studies would not only shed more light on the immunological effects of HA‐based colloidal PECs, which remain barely understood, but also be highly practical in the race to find the safest, most efficacious, and most economical vaccines against newly emerging human viruses, like SARS‐CoV‐2 and new Monkeypox virus variants. Likewise, HA‐based colloidal PECs have not been widely studied for antibiotic delivery.…”

In silico formulation of a next-generation multiepitope vaccine for use as a prophylactic candidate against Crimean-Congo hemorrhagic fever

“…Hence, the study utilizes a different length of the linker as well as an adjuvant to optimize the functional activity of the vaccine construct [ 95 ]. The attached adjuvant not only helps in evoking humoral and cellular immunity but also maintains the longevity of vaccines [ 96 ]. Ultimately, the V1 and V2 vaccines were found to be 260 and 199 long amino acids.…”

Bidirectional and persistent immunomodulation of Astragalus polysaccharide as an adjuvant of influenza and recombinant SARS-CoV-2 vaccine

“…Therefore, there is a significant gap between the vaccines. Adjuvants are essential components of vaccines that can enhance immune responses [29] , [30] . Among these, Aluminum salts are the longest and most commonly used adjuvants that can induce Th2 cell-based responses [31] .…”