Long-Term Immunogenicity and Efficacy of a Reduced Dose of Plasma-Based Hepatitis B Vaccine in Young Adults

By Goh, K. T.; Oon, C. J. et al. | Bulletin of the World Health Organization, July-August 1995 | Go to article overview

Long-Term Immunogenicity and Efficacy of a Reduced Dose of Plasma-Based Hepatitis B Vaccine in Young Adults


Goh, K. T., Oon, C. J., Heng, B. H., Lim, G. K., Bulletin of the World Health Organization


Introduction

When hepatitis B vaccine first became commercially available, it was extremely expensive. Clinical trials on the immunogenicity of reduced doses of the vaccine were therefore conducted in several ocentres. These studies showed that the dose of vaccines from some manufacturers could be reduced without affecting the vaccine-induced antibody response in Anewboms, infants and adults [1-7]. A reduced dose of 5 [mu]g of Merck, Sharp & Dohme (MSD) plasma-based vaccine is as immunogenic and efficacious as the standard dose of 10 [mu]g in preventing perinatal transmission of hepatitis B virus (HBV) [8]. In healthy adults immunized with the MSD plasma-based vaccine, no significant difference in the immune response was observed between groups receiving doses of 40 pg, 20 pg, and 10 pg, and there was 92% seroconversion with the 5-[mu]g dose [9-12]. Similarly, clinical trials with MSD yeast-derived HBV vaccine demonstrated that, for pre-exposure prophylaxis in children aged 1-12 years, the immunogenicity of lower doses (0.6 [mu]g, 1.25 [mu]g, and 2.5 [mu]g was as good as that of the recommended dose (5 [mu]g) [13]. The immunogenicity of reduced doses was also demonstrated for teenagers (2.5 [mu]g) [14-15] and adults [16] (5.0 [mu]g). These findings are of practical importance, especially in developing countries where hepatitis B virus infection is endemic, since the use of a lower dose of vaccine without compromising its immunogenicity and efficacy would reduce considerably the cost of immunization programmes.

In the study, we followed up for 5-6 years two cohorts of seronegative adults who were immunized with a reduced dose of 10 [mu]g of plasma-based HBV vaccine. To the best of our knowledge this is the first long-term follow-up of vaccinees administered such a dose.

Materials and methods

The population groups followed up consisted of preclinical medical and dental students and national service recruits. The Singapore Expert Committee on the Immunisation Programme has recommended that these groups should be protected against viral hepatitis B on a voluntary basis [17].

The purpose of die study was carefully explained to the volunteers and their informed consent was obtained. Prior to vaccination, 5 ml of venous blood was collected from each subject, using disposable needles and syringes, for analyses of various HBV markers. Blood collection was carried out at the Student Health Service Clinic, National University of Singapore, for the students, and at the medical centre of one of the army camps, for the national service recruits.

The blood samples were immediately dispatched to the Hepatitis and Liver Cancer Research Unit, Department of Clinical Research, Singapore General Hospital. The sera were separated, transferred to labelled polypropylene tubes, and stored at -70 [degrees]C before being analysed in batches. The samples were tested for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-body to hepatitis b surface antigen (anti-HBs) using commercially available enzyme immunoassay kits (AUZYME II, CORZYMEE and AUSAB, resp. [sup.a].

Subjects who were negative for HBsAg, anti-HBc and anti-HBs and who had no previous history of hepatitis B vaccination were offered three 10-[mu]g doses of MSD plasma-based HBV vaccine, administered intramuscularly in the deltoid region, at the start of the study and I month and 6 months later. Blood samples were obtained 1, 2, 3, and 5 years after completion of the immunization schedule from the students and after 1, 2, 4, and 6 years from the national service recruits. Since it would not have been ethical to obtain periodic blood samples from those who refused immunization, we tested the sera of unvaccinated national service recruits for HBV markers only once at the end of the 6-year follow-up period. Sera were tested for HbsAg, anti-HBc and anti-HBs. The reciprocal anti-HBs, titres were expressed in mIU/ml, based on a WHO reference standard. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Long-Term Immunogenicity and Efficacy of a Reduced Dose of Plasma-Based Hepatitis B Vaccine in Young Adults
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Author Advanced search

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.