Most Common Virus Transmitted by Blood Transfusion
Hepatitis C virus (HCV) is the most common virus transmitted by blood transfusion, making option C the correct answer. 1
Evidence for HCV as the Leading Transfusion-Transmitted Virus
Hepatitis C virus has historically been the predominant virus transmitted through blood transfusions:
- Before implementation of donor screening, approximately 10% of transfusion recipients developed non-A, non-B hepatitis (later identified as primarily HCV) 1
- Studies demonstrated that 90% of post-transfusion hepatitis was not caused by hepatitis A or B viruses 1
- Historical transmission rates of HCV exceeded 20% in the 1960s 1
Comparison with Other Transfusion-Transmitted Viruses
When comparing the viruses listed in the options:
- Hepatitis A (Option A): Not typically transmitted by blood transfusion as it is primarily spread through the fecal-oral route
- Hepatitis B (Option B): While significant historically, HBV transmission rates were reduced to 0.3%-0.9% per transfusion recipient by the mid-1970s due to improved screening 1
- Hepatitis C (Option C): Historically the most common transfusion-transmitted virus 1
- HIV (Option D): While a serious concern, it has not been the most common transfusion-transmitted virus 2
- CMV (Option E): While transmissible through cellular blood components, it has not been the most common transfusion-transmitted virus 3
Current Risk Reduction Measures
The risk of transfusion-transmitted viral infections has dramatically decreased due to:
- Shift from paid to volunteer blood donors 1
- Implementation of anti-HCV antibody screening and nucleic acid testing (NAT) 1
- Use of surrogate markers like ALT and anti-HBc testing 1
Current risk estimates in the USA have been reduced to between one and four per million blood components transfused for major transfusion-transmitted viruses 2.
Clinical Implications
For clinical practice, it's important to note that:
- Patients with abnormal liver function tests after receiving blood products should be tested for HCV and other hepatitis viruses 1
- Despite advanced screening methods, zero risk has not been achieved, and rare transmissions still occur 4
- Newer technologies such as pathogen inactivation may further reduce transmission risks 4