Vaccine effectiveness of routine infant hepatitis B vaccination/hepatitis B vaccine impact under immunisation programme

Lead Research Organisation: MRC Unit, The Gambia

Abstract

We will check how well the hepatitis B vaccine is working by taking small blood samples from 7,700 people aged from 1 to 21 across the country. By comparing vaccinated people against unvaccinated we will see if the protection against infections with hepatitis B that was seen in earlier studies continues into adulthood. We need to do this as liver disease (especially liver cancer) caused by Hepatitis B is a major killer in The Gambia and as the vaccine was only introduced 21 years ago we do not yet know if the vaccinations given in childhood are going to prevent infections and disease in adults.

Technical Summary

We propose to study the effectiveness of Hepatitis B (HBV) vaccination in infancy against chronic active hepatitis in early adulthood. This will provide new evidence to determine if there is continued protection against HBV carriage and disease after such a long period of time and whether it continues despite the onset of sexual activity. Additionally we will screen those born since the introduction of HBV vaccination into the Expanded Programme of Immunisation (EPI) to further measure the impact of routine vaccination, specifically: what level of carriage is present at different ages; how these appear to be acquired; if rates follow a trend over time; and if there has been a shift in the viral genotype. Approximately 3,200 17-21 year olds from the Gambia Hepatitis Intervention Study (GHIS) will have blood samples taken and 4,500 under 17s who were born since the end of the GHIS will be screened for HBV. This information will inform decisions on the value of a booster dose of vaccine in teenagers, whether there is perinatal transmission that can be averted by giving a first dose of the vaccine on the day of birth, and will describe the performance of the EPI in real life conditions. The existing GHIS, and the following early adoption of the HBV vaccine nationwide, makes this a unique population in which to answer these questions and further define the effectiveness of the HBV vaccine. The large number of blood samples collected will also allow for the genetic testing of host and viruses.
 
Description demonstration of long-term hepatitis B vaccine efficacy in Africa
Geographic Reach Africa 
Policy Influence Type Citation in other policy documents
 
Title Hepatitis B vaccine efficacy survey 2007/8 sera samples and DNA samples stored in Fajara, The Gambia 
Description Under Dr Maimuna Mendy we have approximately 2,700 thousand sera samples and DNA samples from a cross-sectional study that are retained for future use by the Viral Diseases Programme. 
Type Of Material Database/Collection of Data/Biological Samples 
Provided To Others? No  
Impact results from these samples are still being analysed. 
 
Description Community awareness meetings for hepatitis B surveys in The Gambia 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Participants in your research and patient groups
Results and Impact We held meetings to explain the study we were conducting

We had a good response.
Year(s) Of Engagement Activity 2007,2008
 
Description Joint International Tropical Medicine Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Paper Presentation
Geographic Reach National
Primary Audience Health professionals
Results and Impact Presenting work from hepatitis B surveys in The Gambia at a medical conference

none
Year(s) Of Engagement Activity 2012
 
Description Open day at the Medical Research Council Laboratories, The Gambia 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach Local
Primary Audience Schools
Results and Impact We held a stall to explain hepatitis B to secondary school children.

We had good response from the children who attended.
Year(s) Of Engagement Activity 2007
 
Description Presentation at the Clinical Trials Service Unit, University of Oxford 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach National
Primary Audience Health professionals
Results and Impact presenting work from my PhD on hepatitis B in The Gambia

none
Year(s) Of Engagement Activity 2012
 
Description Presentation of data from Gambian HBV surveys to JCVI 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? Yes
Type Of Presentation Paper Presentation
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Unpublished data from the 2007-08 GHIS survey was presented alongside all other HBV efficacy studies as part of a review.

Not yet known, data should confirm the long-term vaccine efficacy of infant HBV immunization in Africa.
Year(s) Of Engagement Activity 2012
 
Description Radio presentation in the Gambia 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact We presented a call-in show on Radio Basse to educate people about hepatitis B and inform communities of a study that we were conducting

We had people phone in with questions and we reached a wide audience
Year(s) Of Engagement Activity 2008
 
Description visit to Ministry of Health in The Gambia 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Primary Audience Health professionals
Results and Impact Discussions with MoH Immunisation team in The Gambia

We are continuing to work in partnership with the health authorities in The Gambia as part of a long term collaboration "The Gambia Hepatitis Intervention Study".
Year(s) Of Engagement Activity 2009