Which statement about HIV transmission risk to healthcare workers is true?

• A. HIV seroconversion rate after a needlestick exposure is about 0.5%, while HBV risk is about 25%
• B. Transmission can occur via casual contact in the hospital
• C. HIV seroconversion rate after exposure is about 50%
• D. HIV cannot be transmitted by needles

Answer: (A)

The main concept is that the risk of acquiring HIV after a percutaneous exposure is relatively low, especially compared with hepatitis B. After a needlestick from an HIV-infected source, the chance of seroconversion is about a few tenths of a percent—roughly 0.3% to 0.5%. In contrast, hepatitis B transmission from a needlestick can be about 25% in an unvaccinated person, because HBV is highly infectious and more likely to persist in blood and on surfaces. This difference in infectiousness explains why the HIV risk is much lower than the HBV risk for needlestick exposures.

Casual contact in a hospital cannot transmit HIV, so that statement is not true. The seroconversion rate is not as high as 50%—that would vastly overstate the risk. And HIV can be transmitted by needles, so that statement is also false.

In practice, despite the low per-exposure risk for HIV, healthcare workers should follow post-exposure procedures promptly, including risk assessment and, when indicated, post-exposure prophylaxis, to minimize any remaining risk.