Simultaneous vaccination against hepatitis A and B: results of an open, randomized study from the occupational health point of view.
OBJECTIVE
The primary objective of the study was to evaluate the immunogenicity of a combined hepatitis A and hepatitis B vaccine compared to the effect of the administration of two monovalent hepatitis A and B vaccines by quantitative measurements of the anti-HBs antibody levels at month 2 of the vaccination course. Secondary objectives were to assess immunogenicity of the vaccines investigated at other time points in the vaccination course (months 1, 6 and 7), including the comparison of quantitative measurements results as well as to evaluate seroconversion and seroprotection rates.


METHODS
The study was designed as open, controlled, randomized, monocentric study with two parallel groups. A total of 304 subjects, aged 18-45 years, were enrolled in the study. Group 1 received a combined hepatitis A and hepatitis B vaccine, group 2 was vaccinated concomitantly with a monovalent hepatitis A and hepatitis B vaccine. Seroprotection against hepatitis B was defined as anti-HBs antibody concentration > or =10 IU/l, and longterm seroprotection as > or =100 IU/l.


RESULTS
In all, 288 subjects completed the study. One month after the second vaccine dose, the percentage of subjects with anti-HBs antibody concentrations > or =100 IU/l as well as the seroconversion rate were significantly higher in group 1 than in group 2. Similarly, anti-HBs GMC was higher after combined vaccination one month after the third vaccine dose (1.684 IU/l vs. 528 IU/l; p < 0,0001). After the vaccination course, all individuals were anti-HAV positive. The overall incidence of symptoms (solicited/unsolicited, local/general) tended to be similar in each of the two groups.


CONCLUSIONS
If health care personnel are exposed to hepatitis A and B virus, the combined vaccination should be preferred to the concomitant one, as this vaccination scheme induced earlier seroprotection against hepatitis B virus infection (> or =10 IU/l and > or =100 IU/l).
Rieger
Monika A
MA
Department of Work Physiology, Occupational Health and Infectiology, Faculty D/Safety Engineering, University of Wuppertal, Wuppertal, Germany. monika.rieger@uni-wh.de
Hofmann
Friedrich
F
Michaelis
Martina
M
D000293:Adolescent; D000328:Adult; D000917:Antibody Formation; D004338:Drug Combinations; D005260:Female; D022362:Hepatitis A Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis
D004338:Drug Combinations; D022362:Hepatitis A Vaccines; D017325:Hepatitis B Vaccines