Efficacy of individual nucleic acid amplification testing in reducing the risk of transfusion-transmitted hepatitis B virus infection in Switzerland, a low-endemic region.
BACKGROUND
The risk of transfusion-transmitted hepatitis B virus (HBV) in Switzerland by testing blood donors for hepatitis B surface antigen (HBsAg) alone has been historically estimated at 1:160,000 transfusions. The Swiss health authorities decided not to introduce mandatory antibody to hepatitis B core antigen (anti-HBc) testing but to evaluate the investigation of HBV nucleic acid testing (NAT).


METHODS
Between June 2007 and February 2009, a total of 306,000 donations were screened routinely for HBsAg and HBV DNA by triplex individual-donation (ID)-NAT (Ultrio assay on Tigris system, Gen-Probe/Novartis Diagnostics). ID-NAT repeatedly reactive donors were further characterized for HBV serologic markers and viral load by quantitative polymerase chain reaction. The relative sensitivity of screening for HBsAg, anti-HBc, and HBV DNA was assessed. The residual HBV transmission risk of NAT with or without anti-HBc and HBsAg was retrospectively estimated in a mathematical model.


RESULTS
From the 306,000 blood donations, 31 were repeatedly Ultrio test reactive and confirmed HBV infected, of which 24 (77%) and 27 (87%) were HBsAg and anti-HBc positive, respectively. Seven HBV-NAT yields were identified (1:44,000), two pre-HBsAg window period (WP) donations (1:153,000) and five occult HBV infections (1:61,000). Introduction of ID-NAT reduced the risk of HBV WP transmission in repeat donors from 1:95,000 to 1:296,000.


CONCLUSIONS
Triplex NAT screening reduced the HBV WP transmission risk approximately threefold. NAT alone was more efficacious than the combined use of HBsAg and anti-HBc. The data from this study led to the decision to introduce sensitive HBV-NAT screening in Switzerland. Our findings may be useful in designing more efficient and cost-effective HBV screening strategies in low-prevalence countries.
Stolz
Martin
M
Blood Transfusion Service SRC Berne, Berne, Switzerland.
Tinguely
Caroline
C
Graziani
Mauro
M
Fontana
Stefano
S
Gowland
Peter
P
Buser
Andreas
A
Michel
Martine
M
Canellini
Giorgia
G
Züger
Max
M
Schumacher
Philippe
P
Lelie
Nico
N
Niederhauser
Christoph
C
D000328:Adult; D000368:Aged; D000465:Algorithms; D001803:Blood Transfusion / Q000706:statistics & numerical data; D003362:Cost-Benefit Analysis; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D017598:Efficiency, Organizational; D019353:Endemic Diseases / Q000517:prevention & control* / Q000706:statistics & numerical data; D005260:Female; D005820:Genetic Testing / Q000191:economics / Q000379:methods / Q000592:standards; D005843:Geography; D006509:Hepatitis B / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission*; D006514:Hepatitis B Surface Antigens / Q000032:analysis / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D021141:Nucleic Acid Amplification Techniques / Q000191:economics / Q000379:methods* / Q000592:standards; D015995:Prevalence; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology; D065227:Transfusion Reaction
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens