Probiotic-derived extracellular vesicles: a novel weapon against viral infections.

Viral diseases remain a significant global challenge. Although vaccination is the primary strategy for preventing viral infections, the rapid evolution of viruses and their divergence from existing vaccines limit vaccine efficacy. Therefore, novel and safe alternatives to combat viral infections are urgently needed. Probiotic-derived extracellular vesicles (PEVs), lipid bilayer-enclosed nanoparticles, exhibit potential as safe alternatives to live bacteria for treating viral diseases. These vesicles deliver antiviral molecules through mechanisms such as blocking viral adsorption/invasion and modulating host immune responses. This review systematically summarizes the biological characteristics of PEVs, their antiviral mechanisms, and their potential applications against respiratory, enteric, and enveloped viruses. Additionally, recent advances in engineering strategies, clinical translation challenges, and future directions for PEVs are discussed.