Immune response to second vaccination series of hepatitis B virus among booster dose non-responders.

OBJECTIVE: To evaluate the response to second vaccination series among post-booster sero-negative children who had previously received compulsory HBV vaccination. SUBJECTS AND METHODS: After given a booster dose to 1070 children, 103 of them failed to generate anamnestic response (anti-HBs <10 IU/L). Only 91/103 children received additional two doses of recombinant HBV vaccine (i.e. 2(nd) vaccination series) after 1 and 6 months post-booster. Blood sample was withdrawn aseptically one month later for quantitative assessment of anti-HBs to detect development of protective immune response (≥10 IU/L). Immunological vaccination failure was assigned to children who did not develop protective immune response after 2(nd) vaccination series. RESULTS: Protective immune response was detected among 84/91 children (92.3%). While 7/91 (7.7%) whose age were ≥10 years did not respond and had post-booster undetectable anti-HBs. About 80% of children with post-booster detectable anti-HBs showed significant protective immune response (anti-HBs ≥100 IU/L) and higher GMT (299.1 ± 3.6 IU/L) compared to those with undetectable 60% and 106.2 ± 12.9 IU/L respectively (P<0.05). No significant difference was detected as regards gender or residence, P>0.05. All children with history of rheumatic fever (7 children) or diabetes mellitus (1 child) developed immune response after 2(nd) vaccination series. CONCLUSION: A booster dose of HB vaccine may be unable to induce sufficient immunological response in children who had undetectable anti-HBs titers. Revaccination for non-responders is an important procedure to increase HBV protection rate.

Effectiveness of hepatitis B virus vaccination program in Egypt: Multicenter national project.

AIM: To assess the effectiveness of hepatitis B virus (HBV) vaccination program among fully vaccinated children. METHODS: A national community based cross-sectional study was carried out in 6 governorates representing Egypt. A total of 3600 children aged from 9 mo to 16 years who were fully vaccinated with HBV vaccine during infancy were recruited. Face to face interviews were carried out and sera were evaluated for hepatitis B surface antigen (HBsAg), anti-HBV core antibodies (total) and quantitative detection of hepatitis B surface antibody using enzyme linked immunoassays techniques. Samples positive to HBsAg/anti-HBV core antibodies were subjected to quantitative HBV-DNA detection by real time polymerase chain reaction with 3.8 IU/L detection limit. RESULTS: Sero-protection was detected among 2059 children (57.2%) with geometric mean titers 75.4 ± 3.6 IU/L compared to 3.1 ± 2.1 IU/L among non-seroprotected children. Multivariate logistic analysis revealed that older age and female gender were the significant predicting variables for having non sero-protective level, with adjusted odds ratio 3.3, 9.1 and 14.2 among children aged 5 to < 10, 10 to < 15 and ≥ 15 years respectively compared to those < 5 years and 1.1 among girls compared to boys with P < 0.01. HBsAg was positive in 0.11% and breakthrough infection was 0.36% and 0.39% depending on positivity of anti-HBc and DNA detection respectively. The prevalence of HBV infection was significantly higher among children aged ≥ 7 years (0.59%) compared to 0.07% among younger children with odds ratio equal to 8.4 (95%CI: 1.1-64.2) and P < 0.01.The prevalence was higher among girls (0.48%) than boys (0.29%) with P > 0.05. CONCLUSION: The Egyptian compulsory HBV vaccination program provides adequate protection. Occult HBV infection exists among apparently healthy vaccinated children. Adherence to infection control measures is mandatory.

Knowledge of and risky behaviours towards hepatitis B virus infection among Egyptian school children.

BACKGROUND AND STUDY AIMS: Success in the prevention of hepatitis B virus (HBV) depends to a large extent on the adolescents' HBV knowledge and their risky behaviours. This study aims to assess the knowledge of and the risky behaviours towards HBV among school students and to determine the significant predictors affecting their knowledge. PATIENTS AND METHODS: A cross-sectional study was approved in four Egyptian governorates (Dakahleya, Gharbeya, Cairo, and Beni-Suef) on 574 students aged 11-17years. A questionnaire was filled through a face-to-face interview to collect data about the socio-demographic character, HBV knowledge, and risky behaviours among children who were chosen for this study. RESULTS: While 75% of students had poor levels of HBV knowledge, 1.7% had good levels of knowledge. As regards gender, more than 60% of students shared scissors and went to dental clinic with no significant difference. While boys reported a significant history of hospitalisation (50.2%) and wound stitches (36%), girls reported a lesser degree of the same (40.2% and 22.6, respectively), p<0.01. During logistic regression analysis, the most important predictors of poor HBV knowledge were age <15years and living in Cairo governorate, with adjusted odds ratio (AOR) 1.5 and 5.0, respectively. CONCLUSION: The majority of students chosen for the study had low levels of knowledge and high risky behaviours towards viral hepatitis. In order to minimise the risky behaviours among adolescents, health education programmes should be conducted concerning the mode of transmission and prevention of viral hepatitis.

Persistence of protection to hepatitis B vaccine and response to booster dose among children and adolescents in Dakahleya- Egypt.

The long-term protective effect of hepatitis B virus (HBV) vaccine and the need for booster dose vaccination remain doubtful. The study aimed to estimate the sero-protection rate and evaluate immune response to a booster dose in children and adolescents with complete HBV vaccination during infancy. According to study design, 902 children were recruited from 2 cities and 3 villages in Dakahleya Governorate by a cross-sectional study; 475 boys and 423 girls with age range 9 months to 16 years. All received the three doses of the compulsory HBV vaccination during infancy. Serum samples were tested for hepatitis B surface antigen (HBsAg) Hepatitis B core antibodies (total) (HBcAb) & quantitative detection of antibodies to hepatitis B surface antigen (anti-HBs) using ELISA. Positive samples for HBsAg/HBcAb were subjected to quantitative HBVDNA detection by real time polymerase chain reaction (PCR). Those proved to have non-seroprotective antibodies (anti-HBs titres < 10 IU/L) were given a booster dose and a blood sample was drawn one month later for evaluation. Results of HBcAb and DNA revealed that 4 children had HBV breakthrough infection (4/902, 0.4% and only one out of them was positive for HBsAg. Out of the 898 children, 57.7% demonstrated sero-protective titers of anti HBs (> or = 10 IU/L) with geometric mean titres (GMTs) of 68.5 +/- 3.5 LU/L. The number of those with non-seroprotective titers was significantly lower among children < 5 years (11.1%) compared to those > or = 10 years (64.8%, P < 0.05), while no significant difference was noticed as regards the gender at any age group. Multivariate logistic analysis revealed that age was the only significant predictor variable for having non- seroprotective antibody level, with adjusted odds ratio (AOR) 4.2 & 14.1 among children aged 5-10 and older respectively compared to those aged < 5 years. About 92% of booster recipients developed anamnestic response. The GMTs of anti-HBs increased significantly. (189.4 +/- 12.3 IU/L), with no gender difference. Multivariate logistic analysis revealed that the pre-booster anti-HBs level < 3.3 IU/L was the only significant predictor variable for non responder to booster dose with AOR 6.6. It is concluded that in spite of the significant decline of level of antibodies over time yet, about half of the studied children have seroprotective level of antibodies after primary compulsory vaccination. Moreover, the developed anamnestic response among children with non-seroprotective level, confirms immunological memory that can outlast the presence of protective level of antibodies.