Hepatitis C is the Most Common Virus Transmitted by Blood Transfusion
The answer is C. Hepatitis C (HCV) is historically the most common virus transmitted by blood transfusion, accounting for the majority of post-transfusion hepatitis cases. 1
Historical Transmission Rates and Evidence
- HCV transmission rates exceeded 20% in the 1960s before modern screening methods were implemented 1
- Before donor screening implementation, approximately 10% of transfusion recipients developed non-A, non-B hepatitis (later identified primarily as HCV) 1
- Studies demonstrated that 90% of post-transfusion hepatitis was not caused by hepatitis A or B viruses, but rather by HCV 1
Comparison with Other Transfusion-Transmitted Viruses
- Hepatitis B (HBV) transmission rates were reduced to 0.3%-0.9% per transfusion recipient by the mid-1970s due to improved screening 1
- While HIV, HTLV, HBV, and HCV are all important transfusion-transmitted viruses, HCV has historically been the most common 2
- The risk of transmission for these viruses has been dramatically reduced to between one and four per million blood components transfused in the USA 2
Risk Reduction Measures
- The shift from paid to volunteer blood donors contributed significantly to reducing transmission rates 1
- Implementation of multiple screening methods has dramatically reduced HCV transmission:
- Anti-HCV antibody screening
- Nucleic acid testing (NAT) for HCV
- Surrogate markers like ALT and anti-HBc testing 1
Current Screening Recommendations
- The European Association for the Study of the Liver (EASL) recommends that blood donor services screen blood donors for hepatitis viruses using NAT, informed by local risk assessment 1
- Patients with abnormal liver function tests after receiving blood products should be tested for HCV and other hepatitis viruses 1
Important Clinical Considerations
- Despite modern screening methods, the risk is not zero, and false negatives can still occur 3
- Current risks of transfusion-associated hepatitis due to HCV are approximately 1 in 125,000 per unit 4
- Background rates of viral hepatitis now greatly exceed the risk of transmission via transfusion, so other sources of infection should be considered when evaluating a patient with hepatitis 4