Immunogenicity and reactogenicity of a combined hepatitis A-hepatitis B vaccine in adolescents.
OBJECTIVE
To evaluate the immunogenicity and reactogenicity of two lots of a combined hepatitis A-hepatitis B vaccine (HAV, HBV) in healthy 15 to 18 year olds.


METHODS
This was a double-blind, randomized clinical study. Vaccine was administered into the deltoid at 0, 1, and 6 months. Immunogenicity was assessed by anti-HAV and anti-HBs antibody levels at 2, 6, and 7 months after the first vaccine dose. Reactogenicity was assessed through use of 3-day diary cards following each vaccination, plus recording other unsolicited reactions.


RESULTS
A total of 160 adolescents were vaccinated; 155 who were seronegative for hepatitis A and B at baseline and who completed the study were included in the immunogenicity analysis. The vaccine was well tolerated; most side effects were local, of low intensity and short duration. Good immunogenicity was determined by antibody titers. High rates of seropositivity (99.4%) were achieved after two doses against HAV, and after three doses for anti-HBs (seroprotection = 98.7%).


CONCLUSIONS
This combination vaccine will be useful for immunizing selected high-risk groups in developed countries. In countries where endemicity is low for both diseases, targeting students prior to risk of acquisition would be a feasible preventive strategy.
Epidemiology and Social Research Unit, Macfarlane Burnet Centre for Medical Research, Fairfield, Victoria, Australia.
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Thompson
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Norris
D000293:Adolescent; D004311:Double-Blind Method; D006506:Hepatitis A / Q000276:immunology / Q000517:prevention & control; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies / Q000097:blood; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D015229:Sexually Transmitted Diseases, Viral / Q000517:prevention & control; D013997:Time Factors; D017778:Vaccines, Combined / Q000009:adverse effects / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000009:adverse effects / Q000276:immunology*
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D017778:Vaccines, Combined; D014761:Viral Hepatitis Vaccines