title: Seroprevalence of anti Vi antibodies and immunogenicity of Typhim Vi vaccine in children.
abstract: This prospective study was carried out on 250 children between 6 months to 5 years of age to determine seroprevalence of anti Vi antibodies and to measure seroresponse and percent seroconversion to TyphimVi polysaccharide vaccine in children 2-5 years of age. Fifty children each were enrolled between 6 to 12 months of age (Group A), between 1- 2 years of age(Group B), between 2-3 years of age (Group C), between 3-4 years of age (Group D) and between 4-5 years of age (Group E). Anti-Vi antibody baseline titres were determined in all children. Children in Groups C to E were vaccinated with Typhim Vi vaccine. Baseline and postvaccination antibody titres were determined by ELISA. Test sera which had antibody levels >1 microg/ml were scored as seropositive. Of 250 children, 3 had base line anti-Vi antibodies >1 microg/ml. Following immunization overall seroconversion rate was 77.5% with 65.3%, 78.2% and 88% children showing seroconversion in Groups C, D and E respectively. Seroconversion was significantly more in Group E children compared to Group C (p=0.0148). There were no significant adverse reactions following vaccination. The study highlights very low prevalence of baseline anti Vi antibodies in children between 6 months and less than 5 years of age and shows high immunogenicity and safety of Typhim Vi polysaccharide vaccine in children 2-5 years of age.
authors.affiliation: Department of Pediatrics, University College of Medical Sciences and Guru Tegh Bahadur Hospital, Delhi, India.
authors.forename: Divya
authors.initials: D
authors.lastname: Gupta
authors.forename: M M A
authors.initials: MM
authors.lastname: Faridi
authors.forename: Anju
authors.initials: A
authors.lastname: Aggarwal
authors.forename: Iqbal
authors.initials: I
authors.lastname: Kaur
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D016009:Chi-Square Distribution; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007194:India; D007223:Infant; D008297:Male; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage* / Q000276:immunology*; D011446:Prospective Studies; D016036:Seroepidemiologic Studies; D014435:Typhoid Fever / Q000276:immunology / Q000517:prevention & control*; D014436:Typhoid-Paratyphoid Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D014505:Urban Population; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D011135:Polysaccharides, Bacterial; D014436:Typhoid-Paratyphoid Vaccines; C057664:Vi polysaccharide vaccine, typhoid