Recent Canadian experience with targeted hepatitis C virus lookback

Area of Science:

• Transfusion Medicine
• Virology
• Public Health

Background:

• Hepatitis C virus (HCV) lookback studies have been conducted in Canada since 1995.
• The effectiveness of HCV lookback has not been re-evaluated since the implementation of advanced HCV screening methods.

Purpose of the Study:

• To determine the yield of targeted HCV lookback in Canada.
• To assess the impact of improved HCV screening tests on lookback efficacy.

Main Methods:

• Data from two Canadian blood suppliers were analyzed.
• HCV lookback data from 1999 to January 1, 2005, were examined for donors positive by antibody screening and/or nucleic acid testing (NAT).

Main Results:

• Lookback involved 498 donations; 160 components were traced to living recipients for HCV testing.
• Seventy-two percent of recipients from pre-second-generation EIA donations were HCV-seropositive.
• Only four recipients from donations tested with second- or third-generation EIA (with or without NAT) were HCV-seropositive, with most cases explained by pre-existing infection or non-infectious transfusion.

Conclusions:

• The yield of HCV lookback appears to be zero when donations were tested with second- or third-generation EIA.
• Coincident infections in recipients may be misattributed to transfusions due to the prevalence of HCV and lack of pretransfusion testing in Canada.
• The necessity of the regulatory requirement for HCV lookback warrants reassessment.