Needlestick Injury - Risk

Risk

While needlestick injuries have the potential of transferring bacteria, protozoa, viruses and prions, from a practical point the transmission of the hepatitis B and hepatitis C viruses and the human immunodeficiency virus (HIV) is important. It is estimated that annually as a consequence there are 66,000 infections with HBV, 16,000 with HCV, and 1,000 with HIV worldwide. In addition, a needlestick injury may lead to significant stress and anxiety for the affected injured person. Taking care of a needlestick injury is costly, estimated to be about $2,500 in the short term in the US.

Hepatitis B carries the greatest risk of transmission, with 37 to 62% of exposed workers eventually showing seroconversion and 22 to 31% showing clinical Hepatitis B infection. The hepatitis C transmission rate has been reported at 1.8%, but newer, larger surveys have shown only a 0.5% transmission rate. The overall risk of HIV infection after percutaneous exposure to HIV-infected material in the health care setting is 0.3%.

The specific risk of a single injury depends on a number of factors when the patients harbor the virus of concern. Injuries with a hollow-bore needle, deep penetration, visible blood on the needle, a needle that was located in a deep artery or vein, or with blood from terminally ill patients are known to increase the risk for HIV infection.

Estimates of the risk of a single injury indicate a risk of 300 HBV infections (30% risk), 30 HCV infection (3% risk) and 3 HIV infections (0.3% risk) per 1,000 respective exposures.

While the vast majority of needlestick injuries occur when the source-person does not carry the HBV, HCV, and HIV and thus do not carry a risk of infection, these events nevertheless cause stress and anxiety and signal a breakdown in protocol and prevention.