Background and objective: Transfusion-transmitted hepatitis
B virus (HBV) infection may originate from hepatitis B surface
antigen (HBsAg) false-negative blood donors, HBsAg negative
and anti-HBc positive blood donors and blood donors with both
tests negative. HBV DNA may be present in all these cases and
blood may be infectious. The aim of the study was to estimate
the risk of transfusion-transmitted HBV in Vietnam using a
stochastic Monte Carlo model.
Methods: A cross-sectional study of HBV prevalence in 1200
potential blood donors in rural Vietnam is used as basis for
the Monte Carlo model together with expert panel estimates of
occult hepatitis B infection (OBI) prevalence in blood donors.
Results: With 1 000 000 blood donors running in the model, the
potential OBI ranged from 658 to 747 blood units per million
at 5 percentile and from 1342 to 2507 blood units per million at
95 percentile resulting in the risk of post-transfusion hepatitis
ranging from 66 to 250 blood units per million assuming that
risk of post-transfusion from potential OBI is 10%. Using the
manufacturer’s HBsAg sensitivity, the mean rate of blood units
per million donations having false-negative HBsAg results was
298 (5–95 percentile: 14–893). When the test sensitivity was set
lower, false-negative tests was observed at a mean of 1087 per
million (5–95 percentile: 762–3220). The fraction of potential
OBI donors increased with the increasing age in both genders.
Conclusion Current HBsAg screening in Vietnam is insufficient
in eliminating the risk of transfusion-transmitted HBV infection.
The major risk factors are HBsAg false-negative results and OBI.
Increased test sensitivity and locally validated HBsAg assays are
recommended.