Letter to Editor: Obesity Vaccine, an Essay on a Preclinical Research

Abstract

Desmond et al. (2025) have recently shown that subcutaneous injections of Mycobacterium vaccae ATCC 15483(M. vaccae) in adolescent male mice significantly prevented excessive weight gain and visceral adiposity induced by a Western-style diet. Despite no change in gut microbiota diversity, this intervention lowered hippocampal neuroinflammation markers (Nfkbia, Nlrp3) and anxiety-like behaviors. Since more than one billion people worldwide and about 30% of Iranian population are influenced by obesity, and this disease caused one in eight deaths from noncommunicable diseases in 2024, these microbiome-based strategies could have clinical value. Such approaches that target immunometabolic pathways represent a promising and interdisciplinary strategy that integrates endocrinology, microbiology, and the psychosomatic aspects of metabolic disorders. Nevertheless, M. vaccae media portrayal as an obesity vaccine causes misunderstanding. This treatment reduces, but does not completely hinder, diet-associated weight gain and could not be replaced with healthy diet habits. However, it could be considered as a supplementary approach to reduce the adverse effects of ultra-processed food consumption and could potentially augment existing obesity treatments, such as microbiome-based interventions, pharmaceutical therapies, and bariatric surgery. More extensive clinical trials are required to determine human efficacy, optimal dosing, safety, and integration with current obesity therapies