Oral vaccine delivery systems: Gastrointestinal barriers, gut microbiota, and emerging engineering strategies.

Engineered nanocarriers, microbial vectors, and bacterial derivatives enhance oral vaccine delivery by overcoming gastrointestinal barriers and improving immune responses.

• Why it matters: Oral vaccines offer many benefits but face significant challenges from the gut environment, immune tolerance, and microbiota variability, limiting their clinical use.
• What they did: The review analyzes physiological and immunological barriers to oral vaccination and evaluates advanced delivery systems, focusing on antigen protection, mucus transport, and cellular uptake.
• The result: These innovative strategies hold promise for more effective oral vaccines, paving the way for broader application and guiding future research in vaccine development.