title: Combined typhoid fever and hepatitis A vaccine: comparison of immunogenicity and safety to concomitant monovalent vaccine over 3 years.
abstract: BACKGROUND
  The safety and immunogenicity of Viatim, a combined hepatitis A (HA) and typhoid fever (Vi) vaccine, were compared with the monovalent component vaccines up to and 1 month after a booster dose at 3 years.
  
  
  METHODS
  Healthy, adult volunteers were randomized to receive Viatim (group A, n = 179) or separate HA and Vi vaccines (group B, n = 181); subgroups were boosted after 3 years with Viatim (groups C and D, n = 56 and 46, respectively). Local and systemic reactions were recorded for 28 days postvaccination. Seroconversion and seroprotection rates and geometric mean antibody concentrations were measured at 14 and 28 days, 1, 2, and 3 years postvaccination, and 28 days after the booster dose.
  
  
  RESULTS
  Local and systemic safety profiles were equivalent between the two groups. Immediate local reactions were infrequent (1 in group A and 2 in group B). Local reactions, consisting mostly of mild or moderate pain, were least frequent with monovalent HA. Antibody concentrations to both antigens were similar in groups A and B, in which HA seroprotection rates (> or = 20 mIU/mL) were respectively, 98.7% and 100% at day 28, and 99.1% and 99.0% after 3 years, achieving 100% after the booster. Vi seroprotection rates (> or = 1 microg/mL) of 85.2% and 84.9% after 28 days fell to 32.1% and 35.6% after 3 years, increasing to 67.3% and 69.8% after the booster dose.
  
  
  CONCLUSIONS
  The combined HA/Vi vaccine, Viatim, had equivalent tolerability and safety and was as rapidly immunogenic as its component monovalent vaccines when given concurrently. A booster dose after 3 years significantly increased antibody levels with some evidence of relative hyporesponsiveness of the typhoid response.
authors.affiliation: Travel Clinic, Havenziekenhuis, Rotterdam, The Netherlands.
authors.forename: David
authors.initials: D
authors.lastname: Overbosch
authors.forename: François
authors.initials: F
authors.lastname: Peyron
authors.forename: Nicole
authors.initials: N
authors.lastname: Picot
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Varichon
authors.forename: Rafaele
authors.initials: R
authors.lastname: Dumas
authors.forename: Laurent
authors.initials: L
authors.lastname: Chambonneau
authors.forename: Françoise
authors.initials: F
authors.lastname: Weber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006506:Hepatitis A / Q000276:immunology / Q000517:prevention & control*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D008297:Male; D008875:Middle Aged; D014435:Typhoid Fever / Q000276:immunology / Q000517:prevention & control*; D014436:Typhoid-Paratyphoid Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D017778:Vaccines, Combined / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology
chemical_list: D022362:Hepatitis A Vaccines; D014436:Typhoid-Paratyphoid Vaccines; D017778:Vaccines, Combined