Vi TYPHOID CONJUGATE VACCINE TYViVAC-TT: RESEARCH TRENDS AND IMPLEMENTATION IN VIETNAM

Abstract

In the global trend of developing new-generation vaccines, conjugate vaccines are considered a promising solution to overcome several limitations of unconjugated polysaccharide vaccines by enhancing efficacy, prolonging immune memory, and expanding the target population, particularly in children under two years of age, thereby contributing to community health protection. Along with above trend, DAVAC implemented and researched to establish a production process for the Vi typhoid conjugate vaccine (TYViVAC-TT), set in-house specification, QC procedures and evaluate vaccine quality. The resulting product met in-house specification and approved by NICVB. Preclinical evaluation on experiment animals demonstrated that the vaccine was safe, non-toxic, and free of abnormal reactions. Imunogenicity studies confirmed that the vaccine elicited a robust antidody response with 100% seroconversion after two doses, higher than the Vi polysaccharide vaccine. The successful establisment of Vi typhoid conjugate vaccine production process in Vietnam along with preclinical evaluation provides a scientific basis for clinical trials and orientation toward industrial-scale development.