Randomized trial to determine safety and immunogenicity of two strategies for hepatitis B vaccination in healthy urban adolescents in the United States

Immunogenicity, effectiveness and safety of combined hepatitis A and B vaccine: a systematic literature review

BACKGROUND

Hepatitis A and B are two of the most common vaccine-preventable diseases and vaccination for Hepatitis A virus (HAV) and hepatitis B virus (HBV) is recommended for those at risk of contracting HAV and/or HBV through their occupation, travel or lifestyle.

OBJECTIVE

To describe the vaccine efficacy, immunogenicity, effectiveness and safety of the combined vaccine against hepatitis A and hepatitis B.

METHODS

A systematic review of the literature published between 1990 and 2015.

RESULTS

Anti-HAV seropositivity rates ranged from 96.2% to 100% and anti-HBs seroprotection rates from 82% to 100%. Antibodies persisted up to 15 years and geometric mean concentration (GMC) remained above the seropositivity cut-off value for both. Anti-HAV and anti-HBs immune responses were lower in less immunocompetent individuals one month after completion of the immunization schedule. The safety profiles of Twinrix(TM) and monovalent hepatitis A and B vaccines were similar.

CONCLUSION

The vaccine offers satisfactory long-term immunogenicity rates, expected duration of protection and safety profile similar to the monovalent hepatitis A or B vaccines.

Ethical Issues in Adolescents' Sexual and Reproductive Health Research in Nigeria

There is increasing interest in the need to address the ethical dilemmas related to the engagement of adolescents in sexual and reproductive health (SRH) research. Research projects, including those that address issues related to STIs and HIV, adverse pregnancy outcomes, violence, and mental health, must be designed and implemented to address the needs of adolescents. Decisions on when an individual has adequate capacity to give consent for research most commonly use age as a surrogate rather than directly assessing capacity to understand the issues and make an informed decision on whether to participate in research or not. There is a perception that adolescents participating in research are more likely to be coerced and may therefore not fully comprehend the risk they may be taking when engaging in research. This paper examines the various ethical issues that may impact stakeholders' decision making when considering engaging adolescents in SRH research in Nigeria. It makes a case for lowering the age of consent for adolescents. While some experts believe it is possible to extrapolate relevant information from adult research, studies on ethical aspects of adolescents' participation in research are still needed, especially in the field of sexual and reproductive health where there are often differences in knowledge, attitudes and practices compared to adults. The particular challenges of applying the fundamental principles of research ethics to adolescent research, especially research about sex and sexuality, will only become clear if more studies are conducted.

Hepatitis B vaccination for reducing morbidity and mortality in persons with HIV infection

BACKGROUND

Hepatitis B vaccine has been recommended for use in people living with HIV (PLHIV) mostly because of the similarities in routes of infection and their prevalence in the same geographic areas. PLHIV may not develop sero-protection after receiving standard hepatitis B vaccine due to their compromised immune status.

OBJECTIVES

To evaluate the efficacy of hepatitis B virus vaccine in PLHIV compared to placebo or no vaccine.

SEARCH METHODS

We searched 6 English language databases in July 2012, and updated the search in June 2013 and August 2014. We searched the grey literature, conference proceedings, specialised web sites, and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials of hepatitis B vaccine compared to placebo or no vaccine, evaluating relevant outcomes of efficacy and safety.

DATA COLLECTION AND ANALYSIS

Two review authors independently sought and extracted data on study design, participants, hepatitis B infection, hepatitis B related morbidity and mortality, anti-HBs immunogenicity and adverse effects related to vaccines from published articles or through correspondence with authors. Data were analysed qualitatively.

MAIN RESULTS

One double-blind randomised controlled trial with 26 participants who were on antiretroviral therapy (ART), comparing hepatitis B vaccine to placebo conducted in Spain met our eligibility criteria and was included in this review. The study ran for three years and participants were followed up on a monthly basis. The study reported adequate humoral response to vaccine at 12 months and no local or systematic side effects in both intervention and control groups. This humoral response was lost when the participants stopped taking ART. The sample size of the study was small and the study was conducted in a high income setting unlike the areas of highest burden of hepatitis B and HIV co-infections.

AUTHORS' CONCLUSIONS

The evidence from this study is insufficient to support any recommendations regarding the use of hepatitis B vaccine in PLHIV. Neither does this evidence demonstrate that hepatitis B vaccine is unsafe in PLHIV. Further randomised controlled trials in high prevalence areas are required to generate evidence on the long term efficacy and safety of hepatitis B vaccine in PLHIV with and without ART. Different regimens and routes of administration should also be explored.

Beyond informed consent: ethical considerations in the design and implementation of sexual and reproductive health research among adolescents

Interest in addressing the ethical issues related to adolescents' engagement in research, especially sexual and reproductive health and rights (SRHR) research is increasing in view of the need to design and implement research that address peculiar SRHR needs of adolescents. These needs include issues of sexually transmitted infections, HIV, AIDS, adverse pregnancy outcomes, community, family and relationship violence and mental health. Unfortunately, adolescents' voluntary participation in research has been limited due to their perceived potential to be coerced into participation, and concerns that they may not fully comprehend the issues related to research risks. As such, many of the regulations for engaging research participants have been defined by age rather than due consideration of psychological development. This paper examines the various potential ethical issues that may impact on decision making when adolescents are engaged in research. These include the need to minimise therapeutic misconception, considerations for recruitment and retention, types and amounts for reimbursement, and engagement of communities of adolescents on advisory boards of studies that involve their population. The potential challenges associated with recruitment of adolescents in early child marriages were also highlighted.

Comprehension of a simplified assent form in a vaccine trial for adolescents

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.