title: Does immunoglobulin interfere with the immunogenicity to Pasteur Mérieux inactivated hepatitis A vaccine?
abstract: OBJECTIVE
  The aim of this study was to compare the immunogenicity of Pasteur Mérieux (P.M. s.v.) inactivated hepatitis A vaccine when given alone with its immunogenicity when given in combination with immunoglobulin.
  
  
  METHODS
  We enrolled 80 healthy volunteers who were seronegative for anti-HAV. Forty subjects (group A) were given two doses of vaccine at 0 and 6 months plus 4 ml of immunoglobulin given simultaneously with the first vaccine injection; and 40 subjects (group B) were given vaccine alone. The population characteristics (age, sex, height and weight) of the two groups were comparable.
  
  
  RESULTS
  Anti-HAV antibody was detectable at week 1 in 100% of group A and in 5.7% of group B, and in 100% of both groups at 4 and 8 weeks. Seroconversion rates (> or = 20 mIU/ml) were 97.4% in group A and 100% in group B at week 24 and were 100% in both groups 4 weeks after a booster injection at 6 months. The antibody response level was lower after concomitant administration of vaccine with immunoglobulin. The antibody geometric mean titer was higher at week 1 in subjects who had been given vaccine and immunoglobulin, but nearly 50% lower at week 4 and thereafter, indicating inhibition of the vaccine-induced immune response by immunoglobulin. At week 28, i.e. 4 weeks after the booster injection, geometric mean titers had increased about 13-15 times in both groups, reaching highly protective antibody levels (3351 mIU/ml in group A and 5843 mIU/ml in group B). No serious adverse effects were observed during the follow-up.
  
  
  CONCLUSIONS
  These data indicate that P.M. s.v. hepatitis A vaccine is highly immunogenic and safe, even when given simultaneously with immunoglobulin. Despite the interference of the immunoglobulin with the active immune response, individuals who were immunized passively plus actively also developed high titers of anti-HAV antibody. It is therefore reasonable to expect that this inhibition will not affect the overall protection conferred by the vaccine.
authors.affiliation: Istituto di Virologia, Universitàdi Milano, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Zanetti
authors.forename: F
authors.initials: F
authors.lastname: Pregliasco
authors.forename: A
authors.initials: A
authors.lastname: Andreassi
authors.forename: A
authors.initials: A
authors.lastname: Pozzi
authors.forename: P
authors.initials: P
authors.lastname: Viganò
authors.forename: A
authors.initials: A
authors.lastname: Cargnel
authors.forename: P
authors.initials: P
authors.lastname: Briantais
authors.forename: E
authors.initials: E
authors.lastname: Vidor
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D022362:Hepatitis A Vaccines; D017957:Hepatitis A Virus, Human / Q000276:immunology*; D006801:Humans; D007115:Immunization Schedule; D007116:Immunization, Passive; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015164:Vaccines, Inactivated / Q000009:adverse effects / Q000276:immunology*; D014761:Viral Hepatitis Vaccines / Q000009:adverse effects / Q000276:immunology*
chemical_list: D022362:Hepatitis A Vaccines; D015164:Vaccines, Inactivated; D014761:Viral Hepatitis Vaccines