What is the most common disease transmitted through a drug user's needle?

• A. HIV
• B. Hepatitis C
• C. Hepatitis B
• D. Syphilis

Answer: (B)

Sharing needles exposes people to bloodborne pathogens, so the main risk comes from percutaneous exposure to infected blood. Hepatitis C stands out as the most commonly transmitted disease in this context because it is highly prevalent among people who inject drugs and is efficiently transmitted through a single contaminated needle. There is no vaccine for Hepatitis C, which makes prevention rely on harm-reduction practices like using clean needles and avoiding share gear.

HIV can be transmitted this way as well, but per exposure, it is less likely to be transmitted than Hepatitis C, and its overall prevalence in this particular context is typically lower. Hepatitis B is highly infectious and can be transmitted via needles too, but widespread vaccination programs have reduced its incidence among injecting drug users, so it is less commonly seen as the top infection in this group. Syphilis is primarily spread through sexual contact rather than through shared needles, so it isn’t the typical needle-transmitted disease in this scenario. Thus Hepatitis C is the best answer.