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1.  Comprehension of a simplified assent form in a vaccine trial for adolescents 
Journal of medical ethics  2013;39(6):410-412.
Introduction
Future HIV vaccine efficacy trials with adolescents will need to ensure that participants comprehend study concepts in order to confer true informed assent. A Hepatitis B vaccine trial with adolescents offers valuable opportunity to test youth understanding of vaccine trial requirements in general.
Methods
Youth reviewed a simplified assent form with study investigators and then completed a comprehension questionnaire. Once enrolled, all youth were tested for HIV and confirmed to be HIV-negative.
Results
123 youth completed the questionnaire (mean age=15 years; 63% male; 70% Hispanic). Overall, only 69 (56%) youth answered all six questions correctly.
Conclusions
Youth enrolled in a Hepatitis B vaccine trial demonstrated variable comprehension of the study design and various methodological concepts, such as treatment group masking.
doi:10.1136/medethics-2012-101286
PMCID: PMC3655100  PMID: 23349510
2.  Randomized Trial to Determine Safety and Immunogenicity of Two Strategies for Hepatitis B Vaccination in Healthy Urban Adolescents in the United States 
Background
Multiple studies have shown excellent response rates after hepatitis B immunization in youth; however, one previous study conducted in urban youth demonstrated poor responses.
Methods
Urban youth, ages 12-17 years, at participating Adolescent Medicine Trials Network for HIV/AIDS Interventions Clinical/Research (ATN) sites were randomized to receive either two doses of Recombivax HB (10mcg hepatitis B surface antigen) or Twinrix (20mcg hepatitis B surface antigen and 720 EL.U hepatitis A antigen) at 0 and 24 weeks. Safety data were collected and antibody measures performed at 0, 28 and 76 weeks.
Results
123 subjects were enrolled and 102 had week 28 serum samples available for antibody measure. A positive response (serum antibody ≥ 10mIU/mL) to hepatitis B antigen was documented in 41/47 (87.2%; 95% confidence interval (CI) 74.3%-95.2%) Recombivax HB recipients and in 52/55 (94.6%; 95% CI 84.9%-98.9%) Twinrix recipients (p=.295). In an adjusted analysis, those identified as Hispanic ethnicity (N=86) were more likely to have a positive response (odds ratio 7.38, 95% confidence interval 1.56-34.95; p=0.0018); whereas those who identified as not heterosexual (N=9) were less likely to respond (odds ratio=0.12, 95%CI, 0.02-0.74). The majority of youth in the Twinrix arm were hepatitis A antibody positive at baseline (26/51; 51%); however, 24/25 hepatitis A antibody negative youth responded to the hepatitis A component. Both vaccines were safe.
Conclusions
Response rate to two doses of Recombivax HB in urban youth is lower than previous studies suggest. The factors associated with diminished response are not known.
doi:10.1097/INF.0b013e3181d285c7
PMCID: PMC3274492  PMID: 20173677
Adolescents; hepatitis B; Vaccination; Immunogenicity
3.  Short-Cycle Therapy in Adolescents after Continuous Therapy with Established Viral Suppression: The Impact on Viral Load Suppression 
Abstract
This was a proof-of-principle study to evaluate the impact of short cycle therapy (SCT; 4 days on/3 days off) in adolescents and young adults with good viral suppression on a protease inhibitor-based antiretroviral regimen. Subjects were recruited by the Adolescent Trials Network for HIV/AIDS Interventions and the Pediatric AIDS Clinical Trials Group. Subjects were infected either through perinatal/early childhood transmission or later via risk behaviors. All subjects were required to have at least 6 months of documented viral suppression below 400 copies/ml plus a preentry value below 200 copies/ml and an entry CD4+ T cell count above 350 cells/mm3. Of the 32 subjects enrolled, 12 (37.5%) had confirmed viral load rebound >400 copies, with 18 subjects (56%) coming off for any reason. The majority of subjects resuppressed when placed back onto continuous therapy using the same agents. Although no difference was found in virologic rebound rates between the early and later transmission groups, those infected early in life had higher rates of coming off SCT for any reason. There was no impact of SCT on the CD4+ T cell counts in those who remained on study or those who came off SCT for any reason. Subjects demonstrated good adherence to the SCT regimen. This study suggests that further evaluation of SCT may be warranted in some groups of adolescents and young adults infected with HIV.
doi:10.1089/aid.2008.0203
PMCID: PMC2853866  PMID: 19534628
4.  Clear and independent associations of several HLA-DRB1 alleles with differential antibody responses to hepatitis B vaccination in youth 
Human Genetics  2009;126(5):685-696.
To confirm and refine associations of human leukocyte antigen (HLA) genotypes with variable antibody (Ab) responses to hepatitis B vaccination, we have analyzed 255 HIV-1 seropositive (HIV+) youth and 80 HIV-1 seronegatives (HIV−) enrolled into prospective studies. In univariate analyses that focused on HLA-DRB1, -DQA1, and -DQB1 alleles and haplotypes, the DRB1*03 allele group and DRB1*0701 were negatively associated with the responder phenotype (serum Ab concentration ≥ 10 mIU/mL) (P = 0.026 and 0.043, respectively). Collectively, DRB1*03 and DRB1*0701 were found in 42 (53.8%) out of 78 non-responders (serum Ab <10 mIU/mL), 65 (40.6%) out of 160 medium responders (serum Ab 10–1,000 mIU/mL), and 27 (27.8%) out of 97 high responders (serum Ab >1,000 mIU/mL) (P < 0.001 for trend). Meanwhile, DRB1*08 was positively associated with the responder phenotype (P = 0.010), mostly due to DRB1*0804 (P = 0.008). These immunogenetic relationships were all independent of non-genetic factors, including HIV-1 infection status and immunodeficiency. Alternative analyses confined to HIV+ youth or Hispanic youth led to similar findings. In contrast, analyses of more than 80 non-coding, single nucleotide polymorphisms within and beyond the three HLA class II genes revealed no clear associations. Overall, several HLA-DRB1 alleles were major predictors of differential Ab responses to hepatitis B vaccination in youth, suggesting that T-helper cell-dependent pathways mediated through HLA class II antigen presentation are critical to effective immune response to recombinant vaccines.
Electronic supplementary material
The online version of this article (doi:10.1007/s00439-009-0720-z) contains supplementary material, which is available to authorized users.
doi:10.1007/s00439-009-0720-z
PMCID: PMC2771141  PMID: 19597844

Results 1-4 (4)