Persistence of immunity 18–19 years after vaccination against hepatitis B in 2 cohorts of vaccinees primed as infants or as adolescents in Italy

Abstract

This study was aimed at assessing the anti-HBs persistence and immune memory 18-19 y after vaccination against hepatitis B in healthy individuals primed as infants or adolescents. We enrolled 405 teenagers (Group A) vaccinated as infants, and 409 young adults (Group B) vaccinated as adolescents. All vaccinees were tested for anti-HBs and anti-HBc antibodies; those found anti-HBc positive were further tested for HBsAg and HBV DNA. Eight individuals belonging to Group B were positive for anti-HBc alone, and were excluded from analysis. Individuals with anti-HBs concentration 10 mIU/ml were considered protected while those with anti-HBs concentration <10 mIU/ml were offered a booster dose and re-tested 2 weeks later. Overall, 67.9% individuals showed anti-HBs concentrations 10 mIU/ml (48.9% in Group A vs 87.0% in Group B, p < 0.001). The antibody geometric mean concentration (GMC) was higher in Group B than in Group A (102.5 mIU/ml vs 6.9 mIU/ml; p < 0.001). When boosted, 94.2% of vaccinees with anti-HBs <10 mIU/ml belonging to Group A and 94.7% to Group B showed an anamnestic response. Post-booster GMCs were similar in both groups (477.9 mIU/ml for Group A vs 710.0 mIU/ml for Group B, p D n.s.). Strong immunological memory persists for at least 18-19 y after immunization of infants or adolescents with a primary course of vaccination. Thus, booster doses are not needed at this time, but additional follow up is required to assess the long-life longevity of protection.

Immune persistence 17 to 20 years after primary vaccination with recombination hepatitis B vaccine (CHO) and the effect of booster dose vaccination

“…A series of studies reported a satisfactory anti-HBs seroconversion, which was approximately 84.0 and 98.0%, after a booster dose was achieved [7, 12–16]. In our study, a dramatic increase in the anti-HBs antibody positive rate was measured.…”

“…Several studies have reported the persistence of anti-HBs levels after primary vaccination and found that protective anti-HBs antibodies were maintained up to 20 years in approximately 37–77% of vaccinees [7–10]. The persistence of anti-HBs is related to a variety of factors, including the mother’s carrying status, regimens and type of vaccine used, time interval between the first and last injection of primary vaccination, and anti-HBs antibody peak level after full course of primary immunization [10–12].…”

Long-term persistency of hepatitis B immunity: an observational cross-sectional study on medical students and resident doctors

“…Furthermore, the higher the antibody response after the primary vaccination cycle, the longer the persistence of an anti-HBs concentration above the 10 mIU/mL threshold [1]. The results arisen in this study reinforce the importance of age at vaccination, as highlighted by the statistical significance in the multivariate analysis (OR 0.2; 95% CI = 0.1-0.8).…”

“…Factors such as age at vaccination, vaccine dosage [1, 3] and host genetic factors [28] play a fundamental role in maintaining the anti-HBs concentration. Furthermore, the higher the antibody response after the primary vaccination cycle, the longer the persistence of an anti-HBs concentration above the 10 mIU/mL threshold [1].…”

“…HBV is one of the main causes of chronic and acute hepatitis, leading to a high risk of death for cirrhosis and liver cancer [1, 2]. …”