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Immunogenicity and Safety Profile of Typhoid Conjugate Vaccine (Vi-DT) Among Nepali Children
Santosh Adhikari1, Ganesh Kumar Rai2, Ram Hari Chapagain3
1Kanti Childrens Hospital, 2 National Academy of Medical Sciences, 3 International Vaccine Institute.
Insights
The typhoid conjugate vaccine (Vi-DT) demonstrated high immunogenicity and a good safety profile in Nepali children, proving non-inferior to the Vi-Tetanus Toxoid (Vi-TT) vaccine. This typhoid vaccine is a promising intervention for tropical regions.
Area of Science:
- * Tropical Medicine
- * Vaccinology
- * Pediatric Infectious Diseases
Background:
- * Typhoid fever is a significant public health issue in tropical regions.
- * An effective typhoid conjugate vaccine (Vi-DT) could enhance existing control strategies.
- * Evaluation of Vi-DT immunogenicity and safety in children is crucial.
Purpose of the Study:
- * To assess the immunogenicity and safety of the Vi-DT vaccine in Nepali children.
- * To compare the efficacy of Vi-DT against a Vi-Tetanus Toxoid (Vi-TT) comparator vaccine.
Main Methods:
- * A randomized, observer-blind, active-controlled phase III clinical trial.
- * Involved 488 children aged 6 months to 17 years.
- * Assessed seroconversion rates (≥4-fold increase in Vi-antibody titer) and adverse events.
Main Results:
- * Seroconversion rates were high and comparable: 98.61% for Vi-DT and 98.36% for Vi-TT.
- * The Vi-DT vaccine showed a good safety profile, with no life-threatening events.
- * Solicited and unsolicited adverse events were recorded for both vaccine groups.
Conclusions:
- * The Vi-DT vaccine is non-inferior to the Vi-TT vaccine in terms of seroconversion.
- * Vi-DT exhibits a favorable safety profile in children.
- * Vi-DT represents a viable vaccine option for typhoid fever prevention.
Background:
Typhoid fever remains a major concern in tropical countries. The availability of an effective vaccine could be an important inclusion to currently available interventions. We reported on our evaluation of the immunogenicity and safety of the typhoid conjugate vaccine (Vi-DT) among Nepali children.
Methods:
The study was an observer blinded, active controlled, randomized phase III clinical trial in children above 6 months and less than 18 years old. Three different lots of Vi-DT(Vi- Diptheria Toxoid); test vaccine and Vi-TT ( Vi-Tetanus Toxoid); comparator vaccines were administered to eligible children. Seroconversion was assessed with blood samples collected at baseline and 4 weeks after the vaccination. A rise of at least 4-fold vi-antibody titer from the baseline was used to indicate positive seroconversion. Data on solicited and unsolicited adverse events were collected.
Results:
Four hundred and eighty-eight children participated in the study. Seroconversion rate was 98.61% and 98.36% among participants who received Vi-DT and Vi-TT vaccines respectively. One immediate adverse event was observed only for Vi-DT group. One hundred forty-two and 66 solicited AEs within 7 days were observed with test and comparator vaccine respectively. Unsolicited AEs within 28 days were 125 for test vaccine compared and 77 for the comparator vaccine. Two SAEs were reported which were Not- related to study vaccine.
Conclusions:
The overall seroconversion in Vi DT vaccine was non inferior to the comparator vaccine and the safety profile of the vaccine was good without any life-threatening events.
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