Wait - do I not know what the word 'vaccine' means?
> OUD [Opioid Use Disorder] is a chronic disorder that even with maintenance therapy has relapse rates approaching 90% largely due to poor medication compliance with current agents [17,18]. Immunotherapy using vaccines can reduce this compliance problem by requiring less frequent administration. Vaccine immunotherapy targets small molecule antigens such as opioid compounds consisting of the antigen (hapten) linked to an immunogenic carrier protein that stimulates the immune system to generate antibodies. An adjuvant is often added to the formulation to increase immunogenicity (antibody formation) against the hapten. After vaccination, when an opioid is consumed, antibodies bind to the target opioid in the periphery and prevent it from getting into the brain or affecting other organs. The kidneys subsequently eliminate bound drug from the body. Numerous pre-clinical studies targeting a broad range of opioids have demonstrated vaccine efficacy [16,19,20,21,22].
> Recent studies testing various formulations of anti-FEN vaccines show efficacy in attenuating the behavioral and lethal effects of FEN and its derivatives [23,24,25] including findings from our group [26]. Our vaccine formulation is composed of a FEN-like hapten containing a linker with a carboxyl moiety suitable for carbodiimide coupling chemistry to form amide bonds to lysine residues on the carrier protein CRM197, a genetically deactivated diphtheria toxin contained in several FDA-approved conjugate vaccines. We combined our conjugate (FEN-CRM) with an adjuvant derived from heat-labile enterotoxins from E. coli (LT) named dmLT or LT(R192G/L211A) that has been combined with other vaccines in several human clinical trials
Perhaps the parent was asking if this technique actually uses the immune system?
(From skimming the article, I think the answer is yes.)