The drug safety testing concept earned a lot of attention

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Vaccines play an important role in modern medicine in the prevention of diseases. Drug safety testing is paramount, as vaccines are often given prophylactically to healthy individuals. Most vaccines work under the basic premise that the immune system becomes primed from a possible future exposure upon vaccination, therefore, providing protection to an individual. In the case of highly purified subunit vaccines that lack intrinsic innate immune activators (natural adjuvants), various types of adjuvants are added during formulation to assist in a better education of the immune system, and thus, provide better protection for any future insult. Developing adjuvants is challenging, and adjuvants are under regulatory scrutiny as a result of theoretical and reported safety concerns, which include the risk of developing autoimmune diseases or AID, even if these concerns are controversial due to confounding factors that may attribute to the onset of AID. While research is constantly evolving to enhance adjuvant design,the scope of this manuscript focuses on two types of adjuvants in marketed vaccines: oil-in-water emulsions

the value of animal models used to study autoimmunity and AID toward studying novel vaccine adjuvants; whether there is scientific evidence indicating an intrinsic risk of autoimmunity and AID with adjuvants, or a higher risk resulting from the mechanism of action; and if there is compelling clinical data linking adjuvants and AID. The tripartite group of experts concluded that there is no compelling evidence supporting the association of vaccine adjuvants with autoimmunity signals. Additionally, it is recommended that future research on the potential effects of vaccine adjuvants on AID should consider carefully the experimental design in animal models particularly if they are to be used in any risk assessment, as an improper design and model could result in misleading information. Finally, studies on the mechanistic aspects and potential biomarkers related to adjuvants and autoimmunity phenomena could be developed.

Autoimmune diseases are complex and multi-factorial disorders, and changes in autoreactive T and B cells homeostasis contribute to the development of autoimmunity. Such changes could, in theory,be induced by non-adjuvanted vaccines but might be even more frequent and plausible with adjuvanted vaccines; therefore, studying autoimmunity risk is important to be considered in the development of adjuvants.So far,there is no compelling clinical evidence that adjuvants are causally related to any autoimmune phenomena.

The drug safety testing concept has earned a lot of attention during the past decade due to the fact it plays a major role in patients’ health. In animals, adjuvants (e.g., IFA and CFA), or components of adjuvants (e.g., oils) are being used to induce autoimmunity disease models in combination with auto-antigens or based on genetic sensitivity. The animal models used in autoimmunity research are not adequate to be used for risk assessment for potential AID for new adjuvanted vaccines in this respect. As shown above, there is no evidence of a link between adjuvanted vaccines and AID so far, but considering there are so many contributing factors in AID, it is challenging and complex to completely rule out a theoretical risk.