HBV VACCINATION PROGRAM IN ITALIAN BLOOD DONORS: EFFECTIVENESS AND POTENTIAL THREAT OF VACCINATION FAILURES TO THE SAFETY OF BLOOD SUPPLY
(Abstract release date: 05/19/16)
EHA Library. Spreafico M. 06/09/16; 135384; LB2273
Dr. Marta Spreafico
Contributions
Contributions
Abstract
Abstract: LB2273
Type: Eposter Presentation
Background
In Italy, vaccination against HBV in newborns, extended to 12-year-old children, was mandated in 1991. Recombinant HBsAg of A2 genotype, aimed to protect across all genotypes, is used. However, occasional reports of infection with non-A2 HBV genotype in vaccinated blood donors presenting with occult HBV infection (OBI: HBsAg negative, HBV DNA positive) raised concerns about the broad genotype efficacy of vaccines as well as to the safety of blood supply. OBI is a potential risk factor for post-transfusion hepatitis, hepatocellular carcinoma, cirrhosis and HBV reactivation.
Aims
The aim of the study was to investigate the efficacy of HBV vaccination in Italy, where HBV D genotype is prevalent.
Methods
In March 2015 we started 12 month project among Italian blood donors vaccinated at 12 years of age (group A) or in infancy (group B). Donors were enrolled and tested for HBsAg, anti-HBc, anti-HBe, anti-HBs titre and HBV DNA. Dilution and avidity tests were performed on anti-HBc positive samples to confirm true positive results. The persistence of anti-HBs according to the time elapsed from vaccination was also evaluated.
Results
Out of 1055 enrolled blood donors, 295 were vaccinated in infancy (28%) and 760 (72%) at 12 years. No anti-HBc positive result was found in group B, whereas 5 donors (0,7%) in group A were anti-HBc positive, HBsAg and HBV DNA negative (p=0.3). Avidity testing confirmed the anti-HBc positivity in 3/5 donors (anti-HBc specificity: 99.72%), all with high avidity. None of them have detectable circulating HBV DNA. One of them, vaccinated at 13 years of age, was also anti-HBe positive. Anti-HBs titres were<10 IU/mL in 381 (36%) subjects, corresponding to 64% of donors vaccinated in infancy (n=189) and 25% of vaccinated at 12 years of age (n=192). Age at vaccination was an independent predictor of low anti-HBs titer (R2: 0.048; 95% CI: 11.14-19.24) by logistic regression analysis.
Conclusion
In Italy, HBV vaccination program in newborns seems to be effective to ensure protection against HBV infection. The prevalence of anti-HBc positivity among donors vaccinated at 12 years of age was low, but further studies are needed to clarify whether vaccinated anti-HBc positive donors are threat for transfusion safety. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy, reflecting a more developed immune system.
Session topic: E-poster
Keyword(s): Hepatitis B virus
Type: Eposter Presentation
Background
In Italy, vaccination against HBV in newborns, extended to 12-year-old children, was mandated in 1991. Recombinant HBsAg of A2 genotype, aimed to protect across all genotypes, is used. However, occasional reports of infection with non-A2 HBV genotype in vaccinated blood donors presenting with occult HBV infection (OBI: HBsAg negative, HBV DNA positive) raised concerns about the broad genotype efficacy of vaccines as well as to the safety of blood supply. OBI is a potential risk factor for post-transfusion hepatitis, hepatocellular carcinoma, cirrhosis and HBV reactivation.
Aims
The aim of the study was to investigate the efficacy of HBV vaccination in Italy, where HBV D genotype is prevalent.
Methods
In March 2015 we started 12 month project among Italian blood donors vaccinated at 12 years of age (group A) or in infancy (group B). Donors were enrolled and tested for HBsAg, anti-HBc, anti-HBe, anti-HBs titre and HBV DNA. Dilution and avidity tests were performed on anti-HBc positive samples to confirm true positive results. The persistence of anti-HBs according to the time elapsed from vaccination was also evaluated.
Results
Out of 1055 enrolled blood donors, 295 were vaccinated in infancy (28%) and 760 (72%) at 12 years. No anti-HBc positive result was found in group B, whereas 5 donors (0,7%) in group A were anti-HBc positive, HBsAg and HBV DNA negative (p=0.3). Avidity testing confirmed the anti-HBc positivity in 3/5 donors (anti-HBc specificity: 99.72%), all with high avidity. None of them have detectable circulating HBV DNA. One of them, vaccinated at 13 years of age, was also anti-HBe positive. Anti-HBs titres were<10 IU/mL in 381 (36%) subjects, corresponding to 64% of donors vaccinated in infancy (n=189) and 25% of vaccinated at 12 years of age (n=192). Age at vaccination was an independent predictor of low anti-HBs titer (R2: 0.048; 95% CI: 11.14-19.24) by logistic regression analysis.
Conclusion
In Italy, HBV vaccination program in newborns seems to be effective to ensure protection against HBV infection. The prevalence of anti-HBc positivity among donors vaccinated at 12 years of age was low, but further studies are needed to clarify whether vaccinated anti-HBc positive donors are threat for transfusion safety. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy, reflecting a more developed immune system.
Session topic: E-poster
Keyword(s): Hepatitis B virus
Abstract: LB2273
Type: Eposter Presentation
Background
In Italy, vaccination against HBV in newborns, extended to 12-year-old children, was mandated in 1991. Recombinant HBsAg of A2 genotype, aimed to protect across all genotypes, is used. However, occasional reports of infection with non-A2 HBV genotype in vaccinated blood donors presenting with occult HBV infection (OBI: HBsAg negative, HBV DNA positive) raised concerns about the broad genotype efficacy of vaccines as well as to the safety of blood supply. OBI is a potential risk factor for post-transfusion hepatitis, hepatocellular carcinoma, cirrhosis and HBV reactivation.
Aims
The aim of the study was to investigate the efficacy of HBV vaccination in Italy, where HBV D genotype is prevalent.
Methods
In March 2015 we started 12 month project among Italian blood donors vaccinated at 12 years of age (group A) or in infancy (group B). Donors were enrolled and tested for HBsAg, anti-HBc, anti-HBe, anti-HBs titre and HBV DNA. Dilution and avidity tests were performed on anti-HBc positive samples to confirm true positive results. The persistence of anti-HBs according to the time elapsed from vaccination was also evaluated.
Results
Out of 1055 enrolled blood donors, 295 were vaccinated in infancy (28%) and 760 (72%) at 12 years. No anti-HBc positive result was found in group B, whereas 5 donors (0,7%) in group A were anti-HBc positive, HBsAg and HBV DNA negative (p=0.3). Avidity testing confirmed the anti-HBc positivity in 3/5 donors (anti-HBc specificity: 99.72%), all with high avidity. None of them have detectable circulating HBV DNA. One of them, vaccinated at 13 years of age, was also anti-HBe positive. Anti-HBs titres were<10 IU/mL in 381 (36%) subjects, corresponding to 64% of donors vaccinated in infancy (n=189) and 25% of vaccinated at 12 years of age (n=192). Age at vaccination was an independent predictor of low anti-HBs titer (R2: 0.048; 95% CI: 11.14-19.24) by logistic regression analysis.
Conclusion
In Italy, HBV vaccination program in newborns seems to be effective to ensure protection against HBV infection. The prevalence of anti-HBc positivity among donors vaccinated at 12 years of age was low, but further studies are needed to clarify whether vaccinated anti-HBc positive donors are threat for transfusion safety. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy, reflecting a more developed immune system.
Session topic: E-poster
Keyword(s): Hepatitis B virus
Type: Eposter Presentation
Background
In Italy, vaccination against HBV in newborns, extended to 12-year-old children, was mandated in 1991. Recombinant HBsAg of A2 genotype, aimed to protect across all genotypes, is used. However, occasional reports of infection with non-A2 HBV genotype in vaccinated blood donors presenting with occult HBV infection (OBI: HBsAg negative, HBV DNA positive) raised concerns about the broad genotype efficacy of vaccines as well as to the safety of blood supply. OBI is a potential risk factor for post-transfusion hepatitis, hepatocellular carcinoma, cirrhosis and HBV reactivation.
Aims
The aim of the study was to investigate the efficacy of HBV vaccination in Italy, where HBV D genotype is prevalent.
Methods
In March 2015 we started 12 month project among Italian blood donors vaccinated at 12 years of age (group A) or in infancy (group B). Donors were enrolled and tested for HBsAg, anti-HBc, anti-HBe, anti-HBs titre and HBV DNA. Dilution and avidity tests were performed on anti-HBc positive samples to confirm true positive results. The persistence of anti-HBs according to the time elapsed from vaccination was also evaluated.
Results
Out of 1055 enrolled blood donors, 295 were vaccinated in infancy (28%) and 760 (72%) at 12 years. No anti-HBc positive result was found in group B, whereas 5 donors (0,7%) in group A were anti-HBc positive, HBsAg and HBV DNA negative (p=0.3). Avidity testing confirmed the anti-HBc positivity in 3/5 donors (anti-HBc specificity: 99.72%), all with high avidity. None of them have detectable circulating HBV DNA. One of them, vaccinated at 13 years of age, was also anti-HBe positive. Anti-HBs titres were<10 IU/mL in 381 (36%) subjects, corresponding to 64% of donors vaccinated in infancy (n=189) and 25% of vaccinated at 12 years of age (n=192). Age at vaccination was an independent predictor of low anti-HBs titer (R2: 0.048; 95% CI: 11.14-19.24) by logistic regression analysis.
Conclusion
In Italy, HBV vaccination program in newborns seems to be effective to ensure protection against HBV infection. The prevalence of anti-HBc positivity among donors vaccinated at 12 years of age was low, but further studies are needed to clarify whether vaccinated anti-HBc positive donors are threat for transfusion safety. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy, reflecting a more developed immune system.
Session topic: E-poster
Keyword(s): Hepatitis B virus
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