A 28-year-old male with opioid use disorder is admitted to hospital following a near-fatal overdose. On investigation, he is found to be co-infected with multiple blood-borne pathogens. Which is the most common blood-borne infection associated with intravenous opioid use in India?

Explanation

## Most Common Blood-Borne Infection in IV Opioid Users **Key Point:** Hepatitis C virus (HCV) infection is the most common blood-borne pathogen among intravenous opioid users in India, with prevalence rates of 40–70% in treatment-seeking populations. ### Prevalence of Blood-Borne Infections in IV Opioid Users | Pathogen | Prevalence in India | Transmission Risk | Chronicity | | --- | --- | --- | --- | | Hepatitis C | 40–70% | Very high (needle-sharing) | 75–85% chronic | | HIV | 5–15% | High (needle-sharing, sexual) | 100% if untreated | | Hepatitis B | 10–20% | Moderate (needle-sharing) | 5–10% chronic in adults | | Hepatitis A | <1% | Fecal-oral (not needle) | Self-limited; no chronicity | **High-Yield:** HCV has the highest prevalence and chronicity among IV drug users. The virus persists in 75–85% of infected individuals, leading to progressive liver disease. ### Why HCV Dominates in IV Opioid Users 1. **Transmission efficiency:** HCV is highly transmissible through blood-to-blood contact via shared needles and injection equipment 2. **Viral persistence:** 75–85% of acutely infected individuals develop chronic HCV infection 3. **Asymptomatic course:** Many infected individuals remain unaware of their status, perpetuating transmission 4. **Needle-sharing behaviour:** Opioid-dependent populations have high rates of equipment sharing due to: - Rapid drug preparation under time pressure - Lack of access to sterile injection equipment - Social and economic factors ### Clinical Implications **Clinical Pearl:** HCV in IV opioid users often progresses to cirrhosis and hepatocellular carcinoma within 20–30 years if untreated. Co-infection with HIV accelerates liver disease progression. **Warning:** Acute HCV infection is often asymptomatic or presents with mild, non-specific symptoms (fatigue, jaundice), leading to delayed diagnosis and continued transmission. ### Comparison with HIV While HIV is more clinically severe and has higher mortality if untreated, HCV is MORE COMMON in the IV opioid population because: - HCV requires only blood-to-blood contact - HIV transmission via needle-sharing is less efficient (~0.63% per needle stick) - HCV has higher seroprevalence in established drug-using networks ### Comparison with Hepatitis B Hepatitis B is less common than HCV in IV opioid users because: - Vaccination programmes have reduced susceptibility - HBV requires higher viral load for transmission - Chronic infection rate is much lower (5–10% in adults) **Mnemonic: HCV-IV** — Hepatitis C is the most common Virus in Intravenous drug users. [cite:World Health Organization (WHO) Hepatitis C Fact Sheet; National AIDS Control Organization (NACO) India HIV Epidemiology]