Current incidence and estimated residual risk of transfusion-transmitted infections in donations made to Canadian Blood Services

Transfusion. 2007 Feb;47(2):316-25. doi: 10.1111/j.1537-2995.2007.01108.x.


Background: New testing methods such as nucleic acid amplification testing (NAT) and chemiluminescent serologic assays have been introduced, more precise estimates for infectious window periods are available, and a new method for estimating the residual risk (RR) of transfusion-transmitted infections (TTIs) has been developed. Thus, available RR estimates for Canada need to be updated.

Study design and methods: Incidence rates for known TTI markers were determined for all allogeneic whole-blood donations made to Canadian Blood Services between 2001 and 2005; they were derived from NAT conversions or seroconversions of repeat donors with at least two donations in a 3-year period. RR estimates for human immunodeficiency virus (HIV)-1 and hepatitis C virus (HCV) derived from the classical incidence/window-period model were compared to those obtained by the new method that estimates incidence from NAT-positive, antibody-negative donations (NAT-yield cases) from all donors divided by person-years.

Results: With the classical method, the RR of HIV (1 per 7.8 million donations) and HCV (1 per 2.3 million) were low; HBV RR was higher (1 per 153,000). HCV RR was significantly lower when estimated with the new method (1 per 13 million). Eleven HCV NAT-yield cases were predicted by applying the classical method to our seroconversion data but only 2 were observed (p = 0.011). Observed HIV-1 NAT-yield cases (n = 1) matched those predicted (n = 0.7).

Conclusion: New tests have reduced an already low risk of TTI in Canada. HCV RR estimates by two different methods differed but both were low.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Banks / statistics & numerical data*
  • Blood Donors
  • Blood Transfusion / statistics & numerical data*
  • Canada / epidemiology
  • Databases, Factual
  • HIV Infections / blood
  • HIV Infections / epidemiology
  • HIV Infections / transmission
  • HIV Seropositivity
  • HIV-1
  • HIV-2
  • HTLV-I Infections / blood
  • HTLV-I Infections / epidemiology
  • HTLV-I Infections / transmission
  • Hepatitis B / blood
  • Hepatitis B / epidemiology
  • Hepatitis B / transmission
  • Hepatitis C / blood
  • Hepatitis C / epidemiology
  • Hepatitis C / transmission
  • Humans
  • Incidence
  • Risk Factors
  • Transfusion Reaction
  • Virus Diseases / blood
  • Virus Diseases / epidemiology*
  • Virus Diseases / transmission*