Objective: A phase IV interventional study with a combined hepatitis A and B vaccine was conducted in HIV-infected children and children receiving immunosuppressive medication for treatment of rheumatic diseases to evaluate immune responses. Methods: Both groups (1-16 years of age) received combined (inactivated) HAV and (rDNA) HBV vaccine Ambirix® at months 0 and 6. Serum samples were taken at four time points and tested for anti-HAV and anti-HBs antibodies. Anti-HAV concentrations ≥20mIU/mL or anti-HBs concentrations ≥10mIU/mL were considered protective. Seropositivity percentages were calculated and geometric mean concentrations (GMCs) were compared by nonparametric Mann-Whitney U-test or Kruskal-Wallis one-way-analysis-of-variance. Results: Of 80 HIV-infected children who completed the study, 67 were HAV-susceptible and 68 HBV-susceptible at enrolment. Of 80 children with rheumatic diseases who completed the study, 65 were HAV-susceptible and 74 HBV-susceptible at enrolment. Immune responses to HAV after first dose of vaccine in both study groups were low: 71% and 55% respectively, whereas immune responses after the second dose were 99% and 100% respectively. Immune response to HBV after first dose of vaccine in both groups was also low: 27% and 17% respectively. Immune responses after the second dose were 97% and 93%, respectively. A larger proportion of children on combination antiretroviral therapy (cART) and of children with viral load <50. copies/mL responded to HBV, and also showed a significantly higher GMC. Conclusions: Although immune response after full series of combined HAV and HBV vaccine in both groups was excellent and comparable to healthy children, a substantial proportion of both groups was not protected for HAV after first dose of vaccine. This protection gap is especially important for HAV in travel health and postexposure prophylactic treatment: both groups of children should be serologically tested for anti-HAV prior to travel to ensure protection if there is no time to await second dose of vaccine.

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doi.org/10.1016/j.vaccine.2013.06.086, hdl.handle.net/1765/71005
Vaccine
Department of Immunology

Belderok, S.-M., Sonder, G., van Rossum, M., van Dijk-Hummelman, A., Hartwig, N., Scherpbier, H. J., … van den Hoek, A. (2013). Evaluation of immune responses to combined hepatitis A and B vaccine in HIV-infected children and children on immunosuppressive medication. Vaccine, 31(38), 4156–4163. doi:10.1016/j.vaccine.2013.06.086