BACKGROUND: In East Asia, individuals systematically vaccinated at birth to hepatitis B virus (HBV) are an increasing part of the blood donor population. Their environment presents a high risk of contact with HBV. HBV vaccine efficacy and potential safety risk carried by vaccinated donors were examined. STUDY DESIGN AND METHODS: A total of 2028 vaccinated blood donors were recruited in 2012 and 2013 and tested for serologic (hepatitis B surface antigen [HBsAg], antibody to hepatitis B surface antigen [anti-HBs], and antibody to hepatitis B core antigen [anti-HBc]) and molecular (HBV DNA) markers of HBV. HBsAg, anti-HBs, and viral load were quantified. RESULTS: Donors 18 to 21 years systematically vaccinated at birth and 22 to 25 years and older donors had both 30.0% negative serology and 1.8% anti-HBc only but the latter group carried significantly higher prevalence of anti-HBc (p < 0.0001). Anti-HBc, mostly associated with anti-HBs, increased from 10.7% at age 18 to 31.5% at age 25. The level of anti-HBs was significantly higher in anti-HBc-positive donors than in anti-HBs-only donors (p < 0.0001). Samples from 24 donors contained low viral load (25 ± 22 IU/mL), half of them undetected by standard nucleic acid testing (NAT), and were classified as four recent infections, 17 occult HBV infections (OBI), and three primary OBIs. Eighteen of 24 carried anti-HBs; 14 of 15 strains were wild-type Genotype B and one was Genotype C. CONCLUSIONS: In an environment of frequent high Genotype B or C viremia, blood donors vaccinated at birth are frequently but mildly infected: asymptomatic and normal alanine aminotransferase level, identified by anti-HBc seroconversion and boosting of anti-HBs. Low viral load and frequent anti-HBs limit transfusion risk.
BACKGROUND: In East Asia, individuals systematically vaccinated at birth to hepatitis B virus (HBV) are an increasing part of the blood donor population. Their environment presents a high risk of contact with HBV. HBV vaccine efficacy and potential safety risk carried by vaccinated donors were examined. STUDY DESIGN AND METHODS: A total of 2028 vaccinated blood donors were recruited in 2012 and 2013 and tested for serologic (hepatitis B surface antigen [HBsAg], antibody to hepatitis B surface antigen [anti-HBs], and antibody to hepatitis B core antigen [anti-HBc]) and molecular (HBV DNA) markers of HBV. HBsAg, anti-HBs, and viral load were quantified. RESULTS: Donors 18 to 21 years systematically vaccinated at birth and 22 to 25 years and older donors had both 30.0% negative serology and 1.8% anti-HBc only but the latter group carried significantly higher prevalence of anti-HBc (p < 0.0001). Anti-HBc, mostly associated with anti-HBs, increased from 10.7% at age 18 to 31.5% at age 25. The level of anti-HBs was significantly higher in anti-HBc-positive donors than in anti-HBs-only donors (p < 0.0001). Samples from 24 donors contained low viral load (25 ± 22 IU/mL), half of them undetected by standard nucleic acid testing (NAT), and were classified as four recent infections, 17 occult HBV infections (OBI), and three primary OBIs. Eighteen of 24 carried anti-HBs; 14 of 15 strains were wild-type Genotype B and one was Genotype C. CONCLUSIONS: In an environment of frequent high Genotype B or C viremia, blood donors vaccinated at birth are frequently but mildly infected: asymptomatic and normal alanine aminotransferase level, identified by anti-HBc seroconversion and boosting of anti-HBs. Low viral load and frequent anti-HBs limit transfusion risk.