What is the most common agent transmitted by blood transfusion: human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), or Cytomegalovirus (CMV)?

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From the Guidelines

The most common agent transmitted by blood transfusion is hepatitis C virus (option c). Despite significant improvements in blood screening procedures, hepatitis C virus remains the most frequently transmitted infectious agent through blood transfusions worldwide, as noted in studies such as 1. This occurs because the virus can have a prolonged window period during which infected donors test negative on screening tests. Hepatitis C virus primarily spreads through blood-to-blood contact, making transfusions a potential route of transmission. The virus causes chronic infection in approximately 75-85% of those infected and can lead to serious liver complications including cirrhosis and hepatocellular carcinoma. While HIV (human immunodeficiency virus), hepatitis B virus, and cytomegalovirus can also be transmitted through blood transfusions, their transmission rates have been significantly reduced through improved donor screening, nucleic acid testing, and other preventive measures, as discussed in 1 and 1. Modern blood banking practices have dramatically decreased the risk of all transfusion-transmitted infections, but hepatitis C remains the most common agent. Some key points to consider include:

  • The risk of transmission of HBV by transfusion of blood or blood products is rare due to routine screening of blood donors for HBsAg, as mentioned in 1.
  • The implementation of viral inactivation procedures and the use of recombinant clotting factor concentrates have eliminated the transmission of HBV via plasma-derived clotting factor concentrates, as noted in 1.
  • Despite these advancements, hepatitis C virus transmission remains a concern due to its prolonged window period and the potential for infected donors to test negative on screening tests. Overall, hepatitis C virus is the most common agent transmitted by blood transfusion, and continued vigilance and improvement in blood screening procedures are necessary to minimize the risk of transmission, as highlighted by the studies 1, 1, and 1.

From the Research

Transfusion-Transmitted Infections

The most common agent transmitted by blood transfusion is a significant concern in the field of transfusion medicine. According to various studies, the answer can be determined by examining the available evidence.

Common Agents

  • Hepatitis B virus (HBV) is a major risk of transfusion-transmitted infection due to the pre-seroconversion window period, infection with immunovariant viruses, and occult carriage of HBV infection 2.
  • Hepatitis C virus (HCV) is also a significant risk, with a residual risk of transmission due to the window period and occult infection 3, 4.
  • Human immunodeficiency virus (HIV) is another agent that can be transmitted through blood transfusion, although the risk has been significantly reduced with the implementation of nucleic acid testing (NAT) 3, 5.
  • Cytomegalovirus (CMV) is also a potential agent that can be transmitted through blood transfusion, although the risk is generally lower than that of HBV and HCV 3.

Prevalence of HBV

  • HBV is the most prevalent transfusion-transmitted infection, with a higher prevalence in countries with poorly developed healthcare systems and limited resources 6.
  • The risk of HBV transmission can be minimized by screening donors, excluding high-risk donors, and implementing NAT 2, 6.

Comparison of Risks

  • The risk of HBV transmission is higher than that of HCV, with an estimated risk of 1 in 63,000 units of blood compared to 1 in 125,000 units for HCV 4.
  • The risk of HIV transmission is significantly lower than that of HBV and HCV, with an estimated risk of less than 1 in 1,000 units of blood 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Transfusion-transmitted infectious diseases.

Biologicals : journal of the International Association of Biological Standardization, 2009

Research

Hepatitis B and blood safety.

Vaccine, 1998

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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