CURABLE BLOOD-BORNE VIRAL INFECTION / CARE & TRANSMISSION
Hepatitis C virus (HCV)
Hepatitis C is primarily blood-borne and is now usually curable. Sexual transmission is less efficient than blood exposure but can occur, especially when blood, mucosal injury or certain overlapping risks are present. A positive antibody test alone does not establish current infection. [46][47][66]
Transmission risk
Risk by type of contact
Bottom line. HCV sexual transmission is usually inefficient in long-term HIV-negative heterosexual couples, but that estimate does not describe every sexual network or traumatic anal exposure. Blood exposure and the source being currently viremic are central.
General
Oral
Vaginal
Anal
Kissing
What changes the risk (4)
- HIV, ulcerative STIs and traumatic anal practices. LOW for a portable multiplier: CDC identifies associations with HIV, proctitis, mucosal trauma and group-sex/chemsex contexts. No universal adjusted per-act factor is available. Sources 2
- Menstruation and ejaculation. LOW: blood exposure is biologically relevant, but no validated menstruation or ejaculation multiplier is available. The small number of transmissions in the heterosexual cohort cannot support one. Sources 1, 2
- Treatment. HIGH for cure evidence: modern direct-acting antivirals cure more than 95% of infections; this is not 95% per-act prevention. Cleared infection does not confer reliable immunity against reinfection. Sources 3
- Vaccination / PEP. LOW for a risk figure: no licensed HCV vaccine or established postexposure antiviral prophylaxis; HIV PrEP/PEP does not prevent HCV. Sources 2
Condoms and dental dams
Condoms are used to reduce potentially infectious blood/body-fluid exposure in relevant contexts, but HCV-specific route-stratified effectiveness has not been quantified adequately for a percentage. Evidence: Low Sources 2
Sources for this risk profile (4)
- Terrault NA et al. Hepatology, 2013. Sexual transmission of hepatitis C virus among monogamous heterosexual couples: the HCV Partners Study. DOI: 10.1002/hep.26164. pubmed.ncbi.nlm.nih.gov
- CDC CDC, 2021. Hepatitis C - STI Treatment Guidelines. cdc.gov
- CDC CDC, 2025. About Hepatitis C. cdc.gov
- CDC CDC, 2024. About STI Risk and Oral Sex. cdc.gov
* How to read these figures. Each is a published estimate under the conditions shown beside it, usually an untreated partner and a single act or partnership. It is not a prediction of your personal risk.
- Evidence: High
- Several prospective studies or a systematic review broadly agree.
- Evidence: Medium
- One or two studies, wide uncertainty, or a model.
- Evidence: Low
- Guideline judgment, case reports, or extrapolation.
Where no risk level is shown, the evidence cannot rank it. That is not the same as low.
Evidence reviewed through 2026-10-27. For reference only; not medical advice.
When to test after a possible exposure
RNA can usually be detected about 1-2 weeks after exposure; antibodies usually take 8-11 weeks.
When to be seen sooner. Suspected acute hepatitis or a significant blood exposure warrants evaluation without waiting for the antibody window.
-
HCV RNA NAT
RNA usually becomes detectable about 1-2 weeks after exposure.
Use RNA when recent infection is suspected, even if antibody testing is negative; early testing may still need follow-up.
Specimens: Blood
Sources 1
-
HCV antibody, with reflex RNA if reactive
Antibodies usually become detectable about 8-11 weeks after exposure.
A positive antibody test needs RNA to identify current infection; recent exposure may require RNA despite a negative antibody result.
Specimens: Blood
Sources 1
Early negatives, after treatment, and screening limits
An early negative result. For a defined occupational exposure, CDC uses RNA at 3-6 weeks and antibody with reflex RNA at 4-6 months if needed. That schedule is not a requirement for every sexual encounter; the clinician adapts follow-up to the exposure and immune status.
After treatment. Antibodies can remain positive after cure. RNA-based assessment, not disappearance of antibody, evaluates current infection or reinfection.
Screening limits. An antibody-positive result does not establish current viremia. Do not equate the earliest RNA-detectable week with a reliable rule-out date.
Kissing and body sites. Blood testing, not a routine throat swab, evaluates HCV. Ordinary kissing is not a typical exposure indication.
Treatment
Oral direct-acting antivirals cure more than 95% of people in typical eight- to twelve-week courses. The regimen depends on liver status, prior therapy and drug interactions. Cure is confirmed with follow-up HCV RNA, not disappearance of antibodies. Cure does not create reliable protection against reinfection. [47][66]
Actions
1. Confirm current infection. An antibody test should be followed by HCV RNA when reactive. Recent exposure or immune suppression may require RNA testing even when antibodies are negative. Tell the clinician about the date and route of contact. [66]
2. Talk with relevant contacts. Current sexual partners, and anyone who shared blood or injection equipment, can be offered a conversation and testing. How far back to look depends on the likely infection period and route, not a fixed window. [46]
3. Follow through after cure. Complete treatment and confirm sustained clearance with the clinician. Future exposure testing uses RNA because antibodies often remain positive. Avoid sharing needles, syringes, drug preparation equipment or items carrying blood. [46][47][66]
SCIENCE & CONTEXT
Hepatitis C / the evidence
History
The virus was molecularly identified in 1989 after years of investigation of non-A, non-B hepatitis. Treatment evolved from prolonged, poorly tolerated interferon-based regimens to short oral direct-acting antiviral courses with high cure rates. The remaining challenges include diagnosis, access, liver damage and reinfection, not a lack of effective treatment. [47][48]
Impact
HCV can stay in the liver for years without symptoms, and over time it can scar the liver. Treatment cures most people, though anyone with advanced scarring may still need regular checks. Tiredness or normal liver tests alone cannot confirm or rule out infection. [46][47]
Antibody positivity means previous exposure or, occasionally, a false-positive result. Detectable RNA establishes current infection. Using antibody prevalence as though every antibody-positive partner can transmit HCV would overestimate the relevant source population. [66]
Probability at a glance
| Finding | What it establishes |
|---|---|
Antibody positive; RNA detectable | Current infection |
Antibody positive; RNA not detected | No current infection detected; may reflect cure or clearance |
Recent contact; antibodies negative | May be too early; consider RNA and follow-up |
Successful antiviral course | More than 95% cure in typical treatment settings |
The relevant probability input would be current RNA-positive infection in a genuinely comparable partner population. A universal multipartner-network value is not established here. [46][66]
The practical conclusion: focus on blood exposure, accurate RNA-based diagnosis and treatment. A history of cured HCV is not equivalent to current infection.