Hepatitis C (HCV) - Comprehensive Overview

1. The Virus

• Genotype 1a: predominates in North America
• Genotype 1b: predominates in Europe
• Genotypes 4 & 5: unique to Africa
• Genotypes 1 and 4 are more resistant to interferon-based therapy (requiring 48 vs. 24 weeks)

2. Epidemiology & Transmission

• ~1% of the world population infected; ~70 million chronic carriers worldwide; >3 million in the US
• Egypt has one of the highest prevalences (~20%), linked to mass schistosomiasis injection campaigns in the 1950s-1980s with reused needles
• High-risk populations (in order of prevalence):
  • Injection drug users (~80% of new cases)
  • Hemophiliacs treated before 1987
  • Blood transfusion recipients before 1990 (blood screening introduced)
  • Hemodialysis patients (~10%)
  • High-risk sexual practices
  • Healthcare workers (~1%)

• Primarily percutaneous blood-to-blood contact
• Mother-to-child vertical transmission: 3-10% (higher if high viral load or HIV co-infection)
• Sexual transmission: inefficient, but accounts for ~10% of new cases; multiple partners is a risk factor
• No risk from breastfeeding
• Average incubation period: 6-7 weeks; seroconversion by ~8-9 weeks; 90% anti-HCV positive within 5 months

3. Pathogenesis & Natural History

• 80% of acute infections are asymptomatic or sub-clinical
• Only 20-30% develop jaundice; 10-20% have nonspecific symptoms (anorexia, malaise, abdominal pain)
• ~75% progress to chronic infection (vs. ~5% for HBV)
• About 50% of chronically infected patients will have persistently elevated ALT; symptoms typically absent for the first 2 decades
• ~20% of chronic patients progress to cirrhosis
• In patients with cirrhosis, risk of hepatocellular carcinoma (HCC) is 1-5% per year
• HCC in HCV is seen almost exclusively in patients who have developed cirrhosis

4. Diagnosis

Serologic Tests

• Window period: Average 10-12 weeks before anti-HCV appears on 2nd-gen EIA
• SVR (Sustained Virological Response): Undetectable HCV RNA 12 weeks after completing treatment - considered a "cure"
• Note: LTT tubes give significantly higher viral load readings than PPTs - collection tube standardization matters for monitoring

5. Treatment

Historical Context

• Old standard: Peginterferon (PEG-IFN) + Ribavirin (RBV) - high side-effect burden (flu-like symptoms, depression, hemolytic anemia, teratogenicity, autoimmune disorders)

Direct-Acting Antivirals (DAAs)

• Sofosbuvir/velpatasvir (Epclusa)
• Glecaprevir/pibrentasvir (Maviret) - 8-12 weeks; SVR >95% across all genotypes
• Sofosbuvir/velpatasvir/voxilaprevir - for treatment-experienced or DAA-failure patients

• SVR rates >95% regardless of genotype
• SVR results in: decreased mortality (HR = 0.27), decreased hepatic decompensation (HR = 0.26), lowered HCC rates (HR = 0.29)
• 5-year survival of 88.6% with SVR achieved in 50.5% of treated patients

Latest Updates (2025-2026)

• Glecaprevir/pibrentasvir (Maviret) received FDA label expansion in 2025 for acute HCV infection (8-week treatment, 96% cure rate) - previously only approved for chronic HCV
• In May 2026, the EMA's CHMP issued a positive opinion for Maviret for acute HCV in adults and children aged 3+ years
• 2025 KASL (Korean) guidelines updated to incorporate pan-genotypic DAA evidence

6. Liver Transplantation Considerations

• HCV was previously the #1 indication for liver transplantation (LT) in the US; after DAAs, it has fallen to the 3rd most common non-neoplastic indication (after alcohol-related liver disease and NAFLD)
• Recurrent HCV post-LT: Previously a major problem; without treatment, leads to accelerated fibrosis and cirrhosis
• DAA-based interferon-free regimens are now highly effective post-LT
• Fibrosing cholestatic hepatitis (FCH): A severe post-LT HCV manifestation (5-10% of cases), characterized by dense portal fibrosis, ductular proliferation, and cholestasis; treatment requires reduced immunosuppression + DAA initiation
• Predictors of severe recurrence include: HCV genotype 1b, high pre/post-LT viral load, multiple rejection episodes, older donor age

7. Complications Summary

8. Key Differences from Other Hepatitis Viruses

• A 2024 systematic review/meta-analysis [PMID 39361017] analyzed drug resistance-associated substitutions following pan-genotypic DAA failure, relevant for managing the small minority with virological failure
• A 2025 review [PMID 40125767] provides an updated summary of HCV epidemiology, treatment, and diagnosis

Sources: Jawetz, Melnick & Adelberg's Medical Microbiology 28e; Henry's Clinical Diagnosis and Management by Laboratory Methods; Sleisenger & Fordtran's Gastrointestinal and Liver Disease; 2025 KASL Clinical Practice Guidelines; FDA/EMA 2025-2026 regulatory updates

• HCV electron micrograph (CDC/Wikimedia)
• HCV structural diagram (Wikimedia)
• Acute hepatitis liver histopathology H&E stain (Wikimedia)