Serological response to hepatitis B virus vaccine in HIV-infected children in Tanzania.
BACKGROUND
HIV-infected children have a lower seroconversion rate to hepatitis B virus (HBV) immunization than healthy children. Previous studies have produced conflicting results on CD4 cell counts as predictors of vaccine response. No study has evaluated the response rate to HBV vaccination in HIV-infected children receiving highly active antiretroviral therapy (HAART). Our aim was to vaccinate HIV-infected children living in a close community and to investigate the anamnestic response rate after vaccination with its predictors.


METHODS
Eighty-four HIV-positive children aged 1-10 years who were negative for antibodies to the HBV core antigen (anti-HBc) completed immunization with three doses of 5 microg HBVAXPRO (Aventis, Milan, Italy). Quantitative testing for antibodies to the HBV surface antigen (anti-HBs) was performed: a seroprotective titre was defined as anti-HBs>10 mUI/mL.


RESULTS
After the vaccination, the anti-HBs seroconversion rate was 59.5%. It was higher in individuals in Centers for Disease Control and Prevention (CDC) immune category 1 than in those in CDC categories 2 and 3. Seroconversion was found in 70.8% of HAART-treated and 44.4% of treatment-naïve children. In multivariable models, HAART use and absolute CD4 cell counts were independently associated with probability of seroconversion and with higher anti-HBs titres.


CONCLUSIONS
We found a higher seroconversion rate compared with previous studies in HIV-infected children. In children who are candidates to receive antiretroviral therapy, it may be advisable to defer HBV vaccination until after treatment initiation.
Pippi
F
F
Clinic of Infectious Diseases, University of Siena, Siena, Italy. pippi.francesco@libero.it
Bracciale
L
L
Stolzuoli
L
L
Giaccherini
R
R
Montomoli
E
E
Gentile
C
C
Filetti
S
S
De Luca
A
A
Cellesi
C
C
D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006801:Humans; D007223:Infant; D008297:Male; D013636:Tanzania
D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines