Current status of hepatitis B immunization and strengthened immune memory among first-year middle school students in Tianjin / 中华预防医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the immunization status of hepatitis B vaccine who were inoculated at birth, HBV infections and the vaccine booster effect in the first-year middle school students (12 - 14 years old).</p><p><b>METHODS</b>A cluster, stratified simplified random sampling method was administrated. The sample size was at least 218, which was calculated by Epi Info 3.3.2 software at 53% the minimum acceptable anti-HBs positive rate and 95% confidence level. A total of 250 and 236 students participated in the infection status and booster immunization effects investigation. The HBsAg, anti-HBs and anti-HBc IgG were detected by Enzyme-linked immunosorbent assay (ELISA). HBV DNA was detected by fluorescence quantitative PCR, and the diagnostic test kit were produced respectively by ABBOTT, Diasorin and Beijing Wantai Biological Pharmacy Enterprise Co.</p><p><b>RESULTS</b>For the immunization status before booster the positive rate of anti-HBs was 62.80% (157/250), the GMT was 73.79 IU/L; the currently HBV infection rate (HBsAg and anti-HBc positive) was 2.80% (7/250). After injection, the anti-HBs positive rate was 94.92% (224/236). Compared with the before booster results, the significant difference was observed (χ(2) = 73.92, P = 0.00). The GMT was 521.15 IU/L, comparing with the before booster results, there was significant difference (t = 15.98, P = 0.00). The anti-HBs conversion rate (from negative to positive) was 91.86% (79/86) after immune-enhancement; of which, 11 students got the second dose of booster vaccine who are no-responders after first injection, in addition 8 students got the anti-HBs.</p><p><b>CONCLUSION</b>It is an effective method to put the first-year middle school students into the immune-enhancement program, so as to improve the immunization memory effect and avoid the loss of protective antibodies.</p>