A two-dose combined vaccine against hepatitis A and hepatitis B in healthy children and adolescents compared to the corresponding monovalent vaccines.
BACKGROUND
Immunization against hepatitis A and B has been available for some time, protecting against both infections. With a view to achieving further reduction in the number of interventions and increasing convenience of the vaccinee, we investigated the reactogenicity and immunogenicity of a combined hepatitis A and B vaccine in healthy 4- to 20-year-old subjects at a 0, 6-month schedule.


METHODS
Two hundred forty-eight study subjects were allocated to two study groups and received either two doses of the combined hepatitis A and B vaccine (68% of subjects) or the corresponding monovalent hepatitis A and hepatitis B vaccines (32% of subjects) concomitantly in opposite arms. Reactogenicity was assessed via diary cards after each vaccination. Serum samples were analyzed at months 1, 2, 6, and 7.


RESULTS
All vaccines were well tolerated and very few symptoms were scored as severe. All but one subject seroconverted for anti-hepatitis A virus (anti-HAV) antibodies (98.6%) and 100% of subjects seroconverted for anti-hepatitis B (HBs) antibodies, with respective seroprotection rates of 98.7% for the combined vaccine group and 95.9% for the concomitant vaccine group (p >0.05), respectively. Geometric mean titers were higher in the group receiving the combined vaccine: 6,635 mIU/mL vs. 2,728 mIU/mL (p = 0.0001) for anti-HAV and 3,362 mIU/mL vs. 1,724 mIU/mL (p = 0.0205) for anti-HBs, respectively. Younger subjects had a stronger immune response compared to older subjects.


CONCLUSIONS
The combined hepatitis A and B vaccine was well tolerated at this two-dose schedule. The combined vaccine had higher immunogenicity, probably explained by a adjuvant effect of the antigens. Vaccination programs requiring fewer injections will most likely have a positive impact on compliance rate and comfort of the vaccinee.
Ramonet
Margarita
M
Unidad de Gastroenterología Pediátrica, Hospital Nacional Alejandro Posadas Haedo, Buenos Aires, Argentina.
da Silveira
Themis Reverbel
TR
Lisker-Melman
Mauricio
M
Rüttimann
Ricardo
R
Pernambuco
Eduardo
E
Cervantes
Yolanda
Y
Cañero-Velasco
Maria Cristina
MC
Falleiros-Carvalho
Luiza Elena
LE
Azevedo
Tania
T
Targa-Ferreira
Cristina
C
Clemens
Sue Ann Costa
SA
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000517:prevention & control*; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines / Q000008:administration & dosage*; D006508:Hepatitis Antibodies / Q000097:blood*; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D017778:Vaccines, Combined / Q000008:administration & dosage
D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D017778:Vaccines, Combined