Salmonella enterica serovars Typhi and Paratyphi are the diseases causing agents of typhoid and paratyphoid fever. These diseases remain significant global health concerns, particularly in regions with inadequate water and sanitation infrastructure. Current vaccination strategies offer only short-term protection and fail to establish long-lasting immunological memory, highlighting the urgent need for improved vaccine formulations. In current study a novel bivalent vaccine formulation targeting Salmonella Typhi and Salmonella Paratyphi B were developed. The vaccine comprises two key components: Salmonella Typhi Vi polysaccharide conjugated to flagellin and purified O-antigen (O-Ag) from Salmonella Paratyphi B. Optimization of conjugation, purification, and characterisation was carried out to confirm the highest quality and efficacy of vaccine components. Comprehensive immunogenicity studies were conducted to evaluate the vaccine's potential. The results demonstrate that both the Vi-flagellin conjugate and the purified O-Ag elicit robust antibody responses in test subjects. Furthermore, safety assessments indicate that the vaccine components are well-tolerated and pose no significant risks. These findings strongly support the potential of our bivalent vaccine formulation as a promising candidate for next-generation typhoid and paratyphoid fever prevention. The ability to induce strong immunogenic responses in opposition to both Salmonella Typhi and Salmonella Paratyphi B in a single formulation represents a significant advancement in field of enteric fever vaccination. This approach may offer a more effective and comprehensive solution to combat these persistent global health threats, particularly in endemic regions where improved long-term protection is critically needed
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How to cite this article: Barot S, Lakshmi B., Preclinical Immunogenicity Studies of Bivalent Conjugated Typhoid and Paratyphoid B Vaccine with Flagella as a carrier at Pilot Scale. Int J Drug Deliv Technol. 2026;16(1s): 212-224; DOI: 10.25258/ijddt.16. 212-224