Abstract:
Background: Hepatitis B virus infection is a major world health problem which is known to
be the main cause of liver failure, cirrhosis, and hepato cellular carcinoma. Production of antiHepatitis
B surface which is stimulated by Hepatitis B Virus vaccine causes protection of
antibody against clinical infection. However, not all vaccinated individuals develop protective
level of antibody against Hepatitis B surface Antigen.
Objective: The main objective of this study was to assess serum level of antibody to hepatitis
B surface antigen among vaccinated and unvaccinated children in Harar town, Eastern
Ethiopia.
Method: Community based Comparative cross sectional study design was conducted among
475 vaccinated and 475 unvaccinated children in Harar town, Eastern Ethiopia. Whole blood
sample (3-5ml) was collected from the study participants who were selected by simple random
sampling from the list of 5-8 years old children in selected kebeles and Enzyme Linked
Immuno-sorbent assay machine was used for detection of total antibodies to Hepatitis B
surface antigen in plasma of collected sample. Pre-tested, structured questionnaire was used
for gathering information about socio demographic characteristics of the study participants
and factors associated with level of antibody. Epi-data version 3.02 was used for data entry.
Data was analyzed using statistical package for social sciences software version 20. Logistic
regressions with 95% CI were used to identify independent predictors of anti-HBs. P-value of
less than 0.05 was taken as level of significance.
Results: The overall sero-protection rate detected in this study was 96.5% among vaccinated
children. However, 7.3% of unvaccinated children had anti-HBs level >10mIU/mL. Protective
antibody levels were detected in 47.2% of vaccinated children five years after vaccination and
it was then decreased to 26.5%, 17.4%, and 5.4% after 6, 7 and 8 years of initial vaccination
respectively. Current age of the child, doses of vaccine and vaccination status were
independent predictors of anti-HBs levels.
Conclusion and Recommendation: protective amount of anti-HBs were detected in 96.5% of
vaccinated children and vaccination of children in infancy produces adequate protection 5 to 8
years post vaccination. However at least unvaccinated children who were born after HBV
vaccine commenced should have to be vaccinated for proper protection from HBV infection.
