Microbial Bioactives | Online ISSN 2209-2161
Volume 8 Number 1 2025
REVIEWS (Open Access)
mRNA Vaccines Influence Gut Microbiome Dynamics Beyond Their Immune Function
Eradah Abu Sabah 1*, Farzad Badmasti 2*
Microbial Bioactives 8 (1) 1-8 https://doi.org/10.25163/microbbioacts.8110459
Submitted: 09 September 2025 Revised: 06 November 2025 Accepted: 12 November 2025 Published: 13 November 2025
Abstract
Messenger RNA (mRNA) vaccines have transformed modern immunization by offering rapid, adaptable protection against emerging infectious threats. Yet as these vaccines become more widely used, an important question has surfaced: how might they affect the gut microbiome, the vast microbial community that shapes immunity, metabolism, and overall health? Because direct evidence remains limited, this systematic review examines pre-2018 research on how traditional, non-mRNA vaccines interact with the gut microbiota to provide meaningful clues. Across studies involving humans and animal models, vaccination often produced temporary shifts in microbial composition and diversity. Some vaccines appeared to encourage the growth of beneficial bacteria that support immune readiness, while others caused brief disruptions or signs of mild dysbiosis—effects that typically resolved as immune activation subsided. These patterns suggest that any immune-stimulating event, including vaccination, can influence the gut indirectly through inflammatory pathways, metabolic changes, and altered host–microbe signaling. By comparing these findings to the immunological mechanisms specific to mRNA vaccines, this review highlights the possibility of similar short-lived microbial adjustments without evidence of long-term harm. The current body of literature points toward a microbiome that is responsive, adaptable, and generally resilient following vaccination. However, the absence of comprehensive, vaccine-specific studies means that definitive conclusions cannot yet be drawn. Overall, this review emphasizes the need for future longitudinal research integrating metagenomics, immunology, and systems biology to fully understand how mRNA vaccines interact with the gut ecosystem. Clarifying these relationships will strengthen vaccine safety monitoring and support more personalized immunization strategies.
Keywords: mRNA vaccine; gut microbiome; microbial diversity; immune modulation; dysbiosis; vaccination effects; host–microbe interactions
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