بررسی اثر واکسیناسیون هپاتیت B و نقش ایمنی‌زایی دوز یادآور در بیماران با تزریق خون مداوم

  Background & Aim: Hepatitis B vaccine is in national vaccination programs. In healthy individuals the immune response is complete d by three-dose injections in 95% of cases and remains complete with time. However, in patients with chronic transfusion this immune response may be incomplete . In such patients, it is advised to check HBs antibody periodically, and use booster dose in cases with low titer of HBs antibody. In the present study we studied the immune status of thalassemic patients for Hepatitis B Virus (HBV) and the booster effects of vaccine.   Patients and Method: Our cross-sectional study was conducted in Adult Thalassemia Clinic in Tehran.We checked Hepatitis B surface antigen (HBsAg), Hepatitis B surface antibody (HBsAb),and Hepatitis B core antibody (HBcAb). We classified the immune status of patients into four categories: 1) immune to HBV via the vaccination (positively vaccinated) if HBsAg:negative, HBsAb:positive, HBcAb:negative2) immune to HBV via the natural disease (past infection) if HBsAg:negative, HBsAb:positive, HBcAb:positive3) non-immune to HBV (negative) if all three parameters were negative4) carrier of HBV (carrier state) if HBsAg was positive and HBsAb and HBcAb were both negative.   We had grading of immunity to HBV vaccine through antibody (HBsAb) titration as below: positive if antibody level was more than 100 IU/mL,negative if antibody level was less than 10 IU/mL, and weakly positive if antibody level was 10-100 IU/mL. SPSS statistical software (version 10) was used for the analysis. We analyzed and compared variables using Pearson and Chi-square tests and p-value for meaningful correlations.   Results: We studied 416 patients including 302 (72.5 %) thalassemia major , 104 (25 %) thalassemia intermediate, 7 sickle thalassemia, and 3 Hb H disease. There were 247 (58.4 %) males and 169 (40.6 %) females with a mean age of 25.6. According to our classification, 289 (69.4%) were positively vaccinated, 80 (19.2 %) were immune to HBV from past infection, 40 (10.5 %) were negative and 3 (0.7 %) were carrier state of HBV. We had 319 (76.6%) cases of HBsAb level more than 100 IU/ml (positive), 77 (18.5 %) between 10-100 IU/mL (weakly positive) and 20 (4.8 %) less than 10 IU/mL (negative).   Conclusion: HBV is one of transfusion transmmitted infections with a high rate of infectivity via tear ,saliva, urine , semen, in addition to blood transfusion. HBV vaccination is obligatory for thalassemics and has been in national vaccination program since 1993. Response rate with vaccination is complete and it is not needed to use booster in healthy people, but for thalassemics it is advised to check the antibody level and administer booster dose for patients with low titer of HbsAb.This protocol can maintain immunity and prevent the decrease in antibody titer in the patients.