[Antibodies persistence after revaccination with three doses of hepatitis B vaccine in non-responsive adults: results from 8-year follow-up study]

Objective: To evaluate the persistence of HBsAg-specific antibodies eight years after revaccination with hepatitis B vaccine (HepB) among adults who were non-responsive to primary immunization. Methods: From August to September 2009, rural communities in Zhangqiu district of Ji'nan city were selected as the study site. The subject's inclusion criteria were 18 to 49 years old, local resident population, without HBV infection history and HepB vaccination history, and good health status. Antibodies against hepatitis B surface antigen (anti-HBs) were detected in adults following the standard primary vaccination. Those who were non-responders (anti-HBs titer <10 mIU/ml) were revaccinated with three doses of HepB and included in the study. Blood samples were collected from all of them at one month (T₁), two years, four years, and eight years after revaccination. The three indexes of anti-HBs, hepatitis B surface antigen (HBsAg), together with antibody against hepatitis B core antigen (anti-HBc), were measured by chemiluminescence microparticle immunoassay (CMIA). Results: The proportion of subjects with anti-HBs titers ≥10 mIU/ml was 85.12% (549/645) at T₁, 60.60% (283/467) at two years, 55.90% (199/356) at four years and 55.09% (222/403) at eight years after revaccination. The first two years' annual decline rates, three to four years and five to eight years, were 15.62%, 3.96%, and 0.36%. The GMC of anti-HBs was 153.92 mIU/ml at T₁, 21.43 mIU/ml at two years, 15.02 mIU/ml at four years, and 13.68 mIU/ml at eight years. In the first two years, three to four years and five to eight years, the annual decline rate of GMC was 62.69%,16.28%, and 2.31%, respectively. Multivariable analysis showed that the titer of anti-HBs at T₁ was independently associated with the persistence of anti-HBs at eight years after revaccination. Compared with anti-HBs titer <100 mIU/ml , those whose anti-HBs titers were 100-mIU/ml and ≥1 000 mIU/ml at T₁ had a higher positive rate of anti-HBs (OR=14.13, P<0.001; OR= 62.91, P<0.001) and a higher probability of anti-HBs titer (β=1.88, P<0.001; β=3.24, P<0.001) at 8 years after revaccination. Nobody was found seroconversion of HBsAg, and the anti-HBc positive rate was 14.14% (57/403). Conclusions: Following revaccination with three doses of HepB in adults who were non-responsive to primary immunization, anti-HBs titers declined rapidly within the first four years. They then maintained a stable level after the fifth year. More than half still kept anti-HBs protective titer at eight years after revaccination. The immunity persistence was associated with anti-HBs titer at one month after revaccination.

[Anti-HBs persistence after revaccination with three doses of hepatitis B vaccine among non-responsive adults: a 4-year of follow-up study]

OBJECTIVE

To explore anti-HBs persistence four years after revaccination with hepatitis B vaccine (HepB) among adults who were non-responsive to HepB primary immunization.

METHODS

A total of 24 237 healthy adults who had no history of hepatitis B infection and hepatitis B vaccination, resided in the local area for more than six months and aged 18-49 years were selected from 79 villages of Zhangqiu County, Shandong Province, China in 2009. Blood samples were obtained and hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected using ELISA method. A total of 11 590 persons who were negative for all of these indicators were divided into four groups by cluster sampling methods. Each group was vaccinated with one of the following four types of HepB at 0-1-6months schedule: 20 μg HepB derived in Saccharomyces cerevisiae (HepB-SC), 20 μg HepB derived in Chinese hamster ovary cell (HepB-CHO), 10 μg HepB-SC and 10 μg HepB derived in Hansenula polymorpha (HepB-HP). Blood samples were collected one month after the third dose of primary immunization and tested for anti-HBs using chemiluminescence microparticle immunoassay (CMIA). The non-responders were followed up and their basic information and the histories of hepatitis B infection, HepB vaccination, smoking and drinking were investigated. Then they were revaccinated with three doses of HepB with the same schedule as the primary immunization. Blood samples were collected from all of them one month (T1), two years and four years after revaccination and anti-HBs, anti-HBc and HBsAg were detected by CMIA. A total of 356 participants were followed up from 645 low-responders four years after revaccination, and the ratio was 55.2%. The risk factors associated with the positive rate and geometric mean concentration (GMC) of anti-HBs after four years of revaccination were analyzed using multivariate unconditional logistic regression model and multivariate linear regression model, respectively.

RESULTS

Among 356 participants, 172 (48.3%) were males and 184 (51.7%) were females. The anti-HBs positive rate was 90.4% (322 cases) at T1 and was 55.9% (199 cases) four years after revaccination. The GMC of anti-HBs was 240.5 (95% CI: 186.4-310.4)mU/ml at T1 and decreased to 15.0 (95%CI: 12.2-18.5) mU/ml four years after revaccination. The average annual decreasing rate of GMC was 50.63% from one month after revaccination to four years after revaccination. The corresponding rate was 64.89% in the first two years, which was 2.12 times the rate in the latter two years (30.57%). When compared with those whose anti-HBs titer was less than 99 mU/ml at T1, the significantly higher anti-HBs four years after revaccination was observed in those whose anti-HBs titer at T1 was 100-999 mU/ml and those whose anti-HBs titer at T1 was ≥1 000 mU/ml. The OR (95%CI) was 7.14 (3.90-13.05) and 28.40 (13.16-61.30) respectively. When compared with those whose anti-HBs titer was ≤99 mU/ml at T1, the GMC of anti-HBs four years after revaccination was also significantly higher among those whose anti-HBs titer at T1 was 100-999 mU/ml and those whose anti-HBs titer at T1 was ≥1 000 mU/ml. The b (95%CI) was 1.66 (1.26-2.05) and 3.16 (2.72-3.60), respectively.

CONCLUSION

The positive rate and GMC of anti-HBs decreased four years after revaccination among non-responsive adults, but still kept anti-HBs above protective level. The immunity durability after revaccination is mainly associated with anti-HBs titer one month after revaccination.