What are the transmission rates of HIV (Human Immunodeficiency Virus), Hepatitis B (HBV), and Hepatitis C (HCV) through a needle stick injury?

Needlestick Transmission Rates of HIV, Hepatitis B, and Hepatitis C

The transmission risk after a single needlestick injury from infected blood is approximately 0.3% for HIV, 1.8% for Hepatitis C, and up to 30% for Hepatitis B (when the source is HBeAg-positive). 1

HIV Transmission Risk

• The risk of HIV transmission after percutaneous exposure to HIV-infected blood is approximately 0.3% (or 0.36% in some studies), which translates to roughly 3 per 1,000 exposures. 1
• This risk is considerably lower than Hepatitis B transmission risk, making HIV the least transmissible of the three bloodborne pathogens via needlestick injury. 1
• The relative infectivity of HIV varies among individuals and over time for a single individual, but no readily available laboratory test exists to measure increased HIV infectivity. 1

Hepatitis C Transmission Risk

• The average transmission risk for Hepatitis C after percutaneous exposure to infected blood is 1.8%, with a reported range of 0-7%. 2
• HCV transmission risk falls between HIV and Hepatitis B in terms of likelihood. 2
• No post-exposure prophylaxis is currently available for Hepatitis C, making early identification through testing the primary management approach. 2, 3

Hepatitis B Transmission Risk

• The risk of HBV transmission after a single percutaneous exposure to HBeAg-positive blood may exceed 30% without prophylaxis, making it the most transmissible of the three bloodborne pathogens. 1, 4
• The presence of HBeAg in serum is associated with higher levels of circulating virus and therefore greater infectivity. 1
• For healthcare workers who have been fully immunized against Hepatitis B and have shown an immune response after vaccination, the risk of transmission is virtually zero. 1
• Without prophylaxis, an estimated 40% of American surgeons become infected during surgery at some point during their lifetime, with 4% becoming carriers. 1

Critical Context for Risk Assessment

• These transmission rates apply specifically to percutaneous injuries (needlestick or sharps injuries) involving hollow-bore needles with vascular access, which represent the highest risk exposure type. 1
• The actual risk in any given exposure depends on multiple factors including the volume of blood involved, the depth of injury, the viral load of the source patient, and whether the needle was used for vascular access. 1
• Mucous membrane exposure or exposure to intact skin carries substantially lower risk than percutaneous injury for all three pathogens. 1, 3

Important Clinical Pitfalls

• Do not assume equal transmission risk across all three pathogens—Hepatitis B is approximately 100 times more transmissible than HIV via needlestick injury. 1
• Do not delay post-exposure prophylaxis decisions while waiting for source patient testing—the window for effective intervention is narrow, particularly for HIV (ideally within hours) and Hepatitis B (within 24 hours, though up to 7 days may still be beneficial). 2, 3
• Do not overlook vaccination status for Hepatitis B—this is the single most important factor determining actual transmission risk for HBV, as vaccinated individuals with documented antibody response have virtually no risk. 1, 2