What is the risk of sexual transmission of hepatitis C virus and how should it be prevented, screened, and treated?

Hepatitis C Sexual Transmission: Risk Assessment and Prevention

Direct Answer

Hepatitis C can be transmitted sexually, but the risk is extremely low in monogamous heterosexual relationships (approximately 1.5% prevalence among long-term partners) and does not warrant routine barrier protection in stable partnerships. 1 However, sexual transmission risk increases substantially among persons with multiple sexual partners, HIV coinfection, men who have sex with men (MSM) with HIV, and those engaging in traumatic sexual practices. 1, 2, 3

Risk Stratification by Population

Low-Risk: Monogamous Heterosexual Couples

• Long-term monogamous heterosexual partners face negligible transmission risk (0-0.6% per year), and barrier protection is not recommended. 1, 2, 4
• Studies of steady spouses show average HCV prevalence of only 1.5% (range 0-4.4%). 1, 5
• The documented case of spousal transmission occurred through direct percutaneous blood exposure during home infusion therapy, not sexual contact. 5, 6

Moderate-Risk: Multiple Sexual Partners

• Persons with multiple sexual partners have 2-3 times higher risk (0.4-1.8% per year), and consistent latex condom use is recommended. 2, 3, 4
• Risk thresholds include: >2 partners in 6 months for acute hepatitis C cases, ≥5 partners/year for blood donors, or ≥10 lifetime partners. 1, 3
• Among high-risk sexual populations (STD clinic patients, sex workers), HCV prevalence averages 6% (range 1-10%) even without injection drug use history. 1, 3

High-Risk: HIV-Coinfected MSM

• HIV-infected MSM engaging in high-risk sexual practices face 4-5 times higher transmission risk compared to HIV-negative men, and barrier protection is strongly recommended. 2, 7, 8
• Traumatic sexual practices (fisting, sex toys, multiple partners) and genital ulcerative disease significantly increase transmission among HIV-positive MSM. 2, 7
• Phylogenetic analysis has documented transmission networks among HIV-infected MSM in urban centers. 8
• HIV-negative MSM without injection drug use have very low HCV prevalence (1.5%), similar to the general population, and do not require routine HCV screening based solely on sexual orientation. 9

Specific Sexual Risk Factors

Practices That Increase Transmission

• Anal intercourse carries higher risk than vaginal intercourse due to increased mucosal trauma and bleeding. 2
• Sexual activity with wounds or bleeding significantly elevates transmission risk. 2, 3
• Failure to use condoms consistently is associated with increased HCV positivity. 1, 3
• History of sexually transmitted infections increases risk. 1, 3

Gender-Specific Transmission Patterns

• Male-to-female transmission appears more efficient than female-to-male transmission (10% vs 3% prevalence when partner is HCV-positive). 1, 3

Prevention Recommendations by Risk Category

For Monogamous Couples (Low Risk)

• No barrier protection required; testing the uninfected partner provides reassurance but is optional. 1, 2
• Counsel to avoid sharing toothbrushes, razors, and any items that may contact blood. 1, 5
• Cover bleeding wounds to prevent blood exposure. 1

For Persons with Multiple Partners (Moderate-High Risk)

• Use latex condoms correctly and consistently for all vaginal and anal intercourse. 1, 2
• Reduce number of sexual partners. 1, 5
• Avoid sexual contact during menstruation or when wounds/bleeding present. 2

For HIV-Infected Individuals (High Risk)

• Mandatory barrier precautions for all sexual activity, particularly for HIV-positive MSM. 1, 2
• Annual HCV screening recommended for HIV-infected MSM engaging in high-risk sexual practices. 2
• Screen for concurrent STIs (syphilis, gonorrhea, chlamydia) which increase transmission risk. 5

Universal Counseling Points

Disclosure and Donation Restrictions

• All HCV-positive persons must inform prospective sexual partners of their status and never donate blood, organs, tissues, or semen. 2, 5

Vaccination

• Vaccinate against hepatitis A and B if not immune, particularly for persons with multiple partners or MSM. 1, 5

Screening Recommendations

• Men who have sex with men are listed as a risk behavior warranting HCV testing in current guidelines. 1
• Sexually active persons about to start HIV PrEP should be screened for HCV. 1
• Screen partners of HCV-positive individuals if they have other risk factors or multiple partners. 2

Critical Clinical Pitfalls

Common Misconception

• When evaluating apparent household or spousal transmission, always exclude direct percutaneous blood exposure first (shared razors, needles, accidental needlesticks), as these are far more likely than sexual transmission. 5, 6
• The documented case of "spousal transmission" in the literature was actually percutaneous exposure during home infusion therapy, not sexual contact. 6

Unacknowledged Risk Factors

• Persons reporting only sexual exposure may have unacknowledged injection drug use, which remains the dominant transmission route (68% of new cases). 1, 5
• 15-20% of acute hepatitis C cases report sexual exposure without other risk factors, but two-thirds have an HCV-positive partner. 1