An active post-marketing surveillance study to evaluate the safety and immunogenicity of Zyvac TCV in healthy participants

AUTHORS

Sanjay Vasant, Chintan Patel, Abhishek Chavan, Ravi Modi, Lisa Sarangi, Virendra Nath Tripathi, et al.

ABSTRACT

Typhoid fever remains a significant public health concern in endemic regions, with increasing antimicrobial resistance heightening the need for preventive strategies such as vaccination. Zyvac-TCV, a typhoid conjugate vaccine developed by Zydus Lifesciences Ltd. is licensed for use across all age groups. This prospective, multicenter, single-arm post-marketing surveillance study evaluated the safety and immunogenicity of Zyvac TCV in 3037 healthy participants aged 6 months to 45 years, enrolled across multiple Indian centers. Each participant received a single 0.5 mL intramuscular dose. Safety was assessed through monitoring of adverse events (AEs) over a 6-month period, while immunogenicity was evaluated in a subset of 300 participants by measuring serum anti-Vi IgG antibody titers at baseline and Day 28 post-vaccination. Overall, 16.7% of participants reported AEs, predominantly mild or moderate in nature, with no serious adverse events. Immunogenicity results demonstrated a seroconversion rate of 94.7% and a significant increase in geometric mean titers from 4.5 U/mL at baseline to 1787.8 U/mL at Day 28. A post-hoc batch analysis showed consistent immunogenicity across three commercial vaccine batches. Zyvac TCV was well tolerated and elicited a strong immune response in all age groups, supporting its integration into national immunization programs in typhoid-endemic regions.

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