A Review on Edible Plant-Based Vaccines: History, Present and Future

Plant-based vaccines have emerged as a potential alternative to traditional immunization strategies, addressing the high production costs, cold-chain dependencies, and logistical constraints that hinder vaccine delivery, particularly in low- and middle-income countries. Over the last two decades, breakthroughs in molecular farming, genetic engineering, and agri-biotechnology have enabled plants to function as bioreactors, producing viral, bacterial, and parasitic antigens, monoclonal antibodies, and immunomodulatory proteins. Edible vaccines, grown in crops such as tomatoes, lettuce, cucumbers, and bananas, can induce both mucosal and systemic immunity, making them a needle-free, conveniently administered, and highly scalable platform. Recent advances emphasize the effective expression of hepatitis B virus antigens, cholera toxin components, Mycobacterium tuberculosis antigens, and veterinary pathogens in various plant tissues, with immunogenicity demonstrated in preclinical and early clinical studies. In addition, advances in nanoparticle-enhanced delivery systems, codon optimization, transient expression platforms, and seed-specific expression have increased protein yield, stability, and biosafety. Plant-based vaccines have the potential to boost or replace conventional vaccines for infectious diseases, such as cholera, hepatitis, tuberculosis, COVID-19, and aquaculture infectious agents, despite ongoing challenges, including insufficient antigen expression, dose standardization, regulatory barriers, and inconsistencies in oral vaccine uptake. Overall, the study highlights the revolutionary potential of plant-based and edible vaccines to enhance global immunization coverage, reduce reliance on cold-chain logistics, and provide cost-effective, rapid-response solutions for both human and animal health.