Viral hepatitis and sexual transmission
Hepatitis A, B and C: how they transmit sexually, and what prevents them.
Hepatitis A
Transmitted faecal-orally, which in a sexual context means oral–anal contact (rimming), fingering followed by hand-to-mouth contact, and shared toys. Large outbreaks among men who have sex with men have been documented repeatedly across Europe and the Americas, including a substantial multi-country outbreak from 2016 to 2018 tracked by ECDC and WHO.
It causes an acute illness — jaundice, fatigue, nausea, abdominal pain — lasting weeks to months. It does not become chronic. Most people recover fully; it is more severe in older adults and in people with existing liver disease.
Prevention: vaccination. Two doses give protection lasting at least 25 years and probably for life. It is recommended for men who have sex with men, people with chronic liver disease, people who inject drugs, and travellers to endemic areas. It is one of the clearest, cheapest interventions in sexual health and is significantly under-taken.
Hepatitis B
Transmitted through blood, semen and vaginal fluid. It is substantially more infectious than HIV by the same routes — historically estimated at 50–100 times more infectious per exposure. Sexual transmission is a major route in low-prevalence countries; mother-to-child transmission dominates globally.
Around 90–95 percent of adults who acquire it clear it spontaneously and become immune. The remainder develop chronic infection, which carries a long-term risk of cirrhosis and hepatocellular carcinoma. Acquisition in infancy produces chronic infection in around 90 percent of cases, which is why birth-dose vaccination matters so much.
Prevention: vaccination, given universally to infants in most countries since the 1990s and available to adults. Three doses; a post-vaccination antibody check is recommended for people at ongoing risk. Condoms reduce transmission. Anyone starting PrEP is tested for hepatitis B first, because tenofovir treats it and stopping abruptly can cause a flare.
Treatment: chronic hepatitis B is suppressed, not usually cured, with antivirals such as tenofovir or entecavir, with monitoring for liver damage and cancer.
Hepatitis C
Primarily bloodborne — historically through unscreened transfusion and now mainly through injecting drug use. Sexual transmission was long considered negligible in heterosexual monogamous couples, and that remains broadly true, with cohort studies finding very low rates.
The exception is significant. Since around 2000, a well-documented epidemic of sexually transmitted hepatitis C has occurred among men who have sex with men, particularly those living with HIV and those on PrEP. The associated factors are consistent across studies: condomless anal sex, group sex, fisting, shared lubricant pots, rectal trauma, chemsex and shared injecting equipment (slamming), and concurrent ulcerative STIs.
Prevention: no vaccine exists. Gloves changed between partners, single-use lubricant, not sharing toys without barriers, not sharing injecting or snorting equipment, and regular testing for those at risk.
Treatment: direct-acting antivirals cure over 95 percent of cases in 8–12 weeks with few side effects — a transformation since 2014, when interferon-based therapy was long, toxic and often ineffective. Reinfection after cure is possible; cure confers no immunity.
Practical summary
| Vaccine | Sexual route | Chronic | Cure | |
|---|---|---|---|---|
| Hepatitis A | Yes | Oral–anal | No | Self-limiting |
| Hepatitis B | Yes | Semen, blood, vaginal fluid | Sometimes | Suppressed, rarely cured |
| Hepatitis C | No | Blood via mucosal trauma | Usually | Yes, over 95 percent |
Get vaccinated against A and B. Test for C if any risk factor applies. Neither PrEP nor condoms alone address hepatitis C in high-risk settings.
Sources
- WHO. Global hepatitis reports and hepatitis A, B and C fact sheets, current editions.
- ECDC. "Hepatitis A outbreaks in the EU/EEA mostly affecting men who have sex with men." Rapid risk assessments, 2017–2018.
- Hagan H et al. "Incidence of sexually transmitted hepatitis C virus infection in HIV-positive men who have sex with men: a systematic review and meta-analysis." AIDS, 2015.
- van de Laar TJW et al. "Evidence of a large international network of HCV transmission in HIV-positive men who have sex with men." Gastroenterology, 2009.
- BASHH. UK national guidelines on the management of viral hepatitides, current edition.
- Van Damme P et al. Long-term protection after hepatitis A and B vaccination, review evidence.
Last reviewed: August 2026.
Educational reference, not medical advice. Every article is community-edited and cites its sources; verify anything that affects your health with a clinician who knows your history.