vaccinadjuvanter

Vaccinadjuvanter are substances added to vaccines to enhance the immune response to an incorporated antigen. They can increase the magnitude and duration of antibody and T-cell responses, improve protection in populations with weaker responses, and enable dose-sparing or reduced number of doses. Adjuvants are not required for all vaccines; many vaccines, such as those based on live attenuated pathogens, rely on inherent immunogenicity and do not use added adjuvants.

Mechanism: Adjuvants stimulate innate immune pathways by engaging pattern-recognition receptors, promoting antigen uptake and presentation by dendritic cells, and inducing cytokines and chemokines that shape adaptive immunity. The depot effect was historically proposed but is not the sole mechanism; different adjuvants activate distinct receptors and lead to different biases toward antibody or cellular responses.

Common types include aluminum salts (alum), the oldest and most widely used; oil-in-water emulsions such as MF59 and AS03; liposome-based systems such as AS01 and AS02; and MPL-containing formulations such as AS04. These adjuvants are often used in subunit or protein-based vaccines to enhance immunogenicity and allow antigen dose reductions. Examples of vaccines that use adjuvants include vaccines with AS04 and shingles vaccines with AS01/AS01B.

Regulatory oversight and safety: Adjuvants undergo pre-licensing evaluation for safety and efficacy and are monitored after approval. Local reactions at the injection site are common; systemic adverse events are generally rare. Decisions about use in particular populations (children, elderly, pregnant individuals, immunocompromised people) depend on risk-benefit assessments and regulatory guidelines.

Research and status: Vaccine adjuvant research seeks to expand options, tailor responses to specific antigens, and improve protection against challenging pathogens. Several adjuvants are in various stages of development or approval, with ongoing evaluation of long-term safety and effectiveness.