Pattern of responses to hepatitis b virus vaccine in Basrah, Iraq

الملخص EN

A serological study was carried out in Basrah governorate, southern Iraq, from October 2004 to the end of September2006 aimed at estimating the prevalence of HBs-antibody among four groups of individuals : Children under 15 years of age, medical personnel, barbers and unvaccinated adults, to determine HBV vaccination coverage in our area, also to evaluate the duration of vaccine induced immunity and the rate of waning immunity as well as the determination of the proportion of hepatitis type B among the other causes of hepatitis occurring in the community.

A total of 762 individuals were included in the study from whom blood samples were collected.

The overall vaccination coverage among the study population was 62.9% leaving 37.1% unvaccinated.

An enzymelinked Immunosorbent assay (ELISA) was used for the determination of anti-HBs-IgG antibody, showed a prevalence of 71.2%, 66.7%, 51.4%, and 8.7% for barbers, medical personnel (occupational exposure), children under 15years of age and unvaccinated adults respectively.

There was a clear effect for the number of vaccine doses administered on the levels of seroconversion, with no significant differences in antibody associated with sex or geographical distribution of vaccinees, but there was a difference in relation to occupation.

There was a significant decline in the levels of antibody overtime post vaccination and the losses of protective levels of antibodies were quite evident by 3-4 years post the primary vaccine doses which stress the need for booster doses.

In the primary vaccination schedule the time interval of 5-6 months between the 2nd and 3rd vaccine doses is suitable for better responses to HBV vaccine.

The proportion of icteric HB was 14.7% while 85.3% was due to other hepatitis causes, and the rate of hepatitis B among individuals with no history of hepatitis was 2.6% referring to the subclinical cases.