| المستخلص: |
Use of recent serological methods to determine the level of Hepatitis B virus surface antibodies (HBsAb) in different age groups of the general population of Taif governorate, KSA who had been previously vaccinated against Hepatitis B Virus (HBV) (since year 1410H) or non-vaccinated (10 years before 1410H) would enable us to highlight the immune status of the Saudi population against infection by HBV. In addition, detection of HBsAg and HBcAb in serum of such people was performed to survey cases that became infected despite being vaccinated. We collected a number of 1056 blood samples from different ages (1 day post birth till 31 years) to perform this study. ELISA method was used in collected blood samples to (i) quantitate the level of HBsAb and thus determine the immune status against HBV (ii) detect HBsAg and HBcAb to diagnose HBV infection. Afterwards, confirmation of viral infection in ELISA-positive blood samples was achieved by use of Real Time PCR to detect viral DNA. Data revealed that there was no significant difference between the immune status of vaccinated and non vaccinated individuals. Among the vaccinated individuals tested for HBcAb there was 28 positive cases out of 736, comprising 3.8% of the total tested samples. The percentage of HBcAb positive cases in non-vaccinated individuals was higher (4.1%) than of vaccinated individuals which was 3.8%. Data showed that only 8 samples were positive for HBsAg among 1056 samples. Among vaccinated individuals there were 6 positive cases for HBsAg (0.8%). Results showed that the number of positive cases for HBsAg was higher in vaccinated individuals than in the non-vaccinated. The phylogenetic tree showed the viral isolates of this study was lied in the same cluster with the Hepatitis B virus surface antigen gene, complete cds (J02205.1). We conclude that relationship between the decrease in HBV-antibodies in the blood of vaccinated people and their immune status against HBV infection should be examined in order to define people who need to be re-vaccinated with other protective booster dose or not. Accordingly, we recommend that testing for HBsAb would be included in the healthy marital screening program for viral infections as well as for blood donors. Non-immune individuals would then be administered the vaccine immediately. Further efforts for increasing the immunity against such human virus should be done.
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