Hepatitis A, B, and C are three different liver viruses with different routes. Hepatitis A spreads mainly fecal-orally — including through oral-anal sexual contact — and clears completely. Hepatitis B and C spread through blood and bodily fluids during sex and can become chronic. Vaccines prevent A and B; condoms and testing cut the risk for all three.
| Item | Reported cases |
|---|---|
| 2020 | 9,952 |
| 2021 | 5,728 |
| 2022 | 2,265 |
| 2023 | 1,648 |
How hepatitis A, B, and C are actually transmitted
The three viruses share a target, the liver, but reach it by different paths, and that difference shapes how you protect yourself. Knowing the mechanism keeps you from worrying about the wrong thing while the real risk goes unaddressed. For a plain-language overview of all three side by side, start with our guide to hepatitis a, b, c's: hepatitis a, b, c's.
Hepatitis A
Hepatitis A is a viral liver infection caused by the hepatitis A virus (HAV), and unlike B and C it does not cause chronic infection — people recover completely CDC, About Hepatitis A. It spreads by the fecal-oral route, which means the virus has to be swallowed, even in microscopic amounts, through contaminated food or water or close personal contact. Sexually, that translates to oral-anal contact (rimming) and to fingers or objects that move from the anal area to the mouth. Because it takes only a tiny dose, outbreaks have hit men who have sex with men, people who use drugs, and people experiencing homelessness. The illness ranges from no symptoms at all to weeks of fatigue, nausea, and jaundice — see hepatitis a symptoms and how long they last for the full timeline: hepatitis a symptoms and how long they last.
Hepatitis B
Hepatitis B is a bloodborne and sexually transmitted liver virus that travels in blood, semen, and vaginal fluids. During sex it enters through tiny breaks in the lining of the genitals, anus, or mouth, which makes it far more efficiently transmitted than HIV through the same exposures. It can also pass by sharing needles or other drug equipment. Some adults clear it; others develop a chronic infection that quietly damages the liver over years, raising the risk of cirrhosis (permanent scarring that stops the liver working) and liver cancer. A vaccine prevents it.
Hepatitis C
Hepatitis C is primarily bloodborne, and sharing needles or other injection equipment is the dominant route. Sexual transmission does happen, mostly through practices that involve blood contact, such as condomless anal sex or sex during menstruation, and it's seen more often among men who have sex with men living with HIV. Most people who get hepatitis C develop a chronic infection if untreated, but modern oral medications cure the great majority. There is no vaccine for hepatitis C, so prevention rests on avoiding blood contact and getting tested.
How these viruses are NOT spread
Worry tends to attach to the wrong things. None of these viruses spreads through ordinary, non-sexual contact. You will not catch hepatitis A, B, or C from:
- Toilet seats, doorknobs, or other surfaces in normal daily use.
- Sharing towels, dishes, cups, or utensils in passing.
- Hugging, holding hands, or sitting beside someone.
- Coughing or sneezing — these are not airborne respiratory viruses.
- Saliva alone from casual contact such as a closed-mouth greeting.
Hepatitis A is the one exception to be precise about: it isn't airborne, but it can ride on contaminated food, water, or unwashed hands that reach the mouth. Handwashing after using the bathroom and before eating actually interrupts spread, and isn't just a token gesture.
Who's at higher risk
Risk clusters around specific exposures rather than around any "type" of person. The groups carrying the highest burden include:
- Men who have sex with men, particularly for hepatitis A (oral-anal contact) and for hepatitis C among those living with HIV.
- People who inject drugs or share any injection equipment — the leading route for hepatitis C and a major one for hepatitis B.
- People experiencing homelessness, who featured heavily in recent hepatitis A outbreaks.
- Anyone with multiple partners or a partner who has hepatitis B or C.
- Infants born to a parent with hepatitis B, who can be infected during birth.
Reducing the risk
Two tools do most of the work: vaccines and barriers. Hepatitis A is vaccine-preventable, and vaccination is the single best way to prevent it; good hand hygiene helps limit spread on top of that. Hepatitis B has its own vaccine, and the combined twinrix vaccine covers both A and B in one series, which is a sensible choice if you're at risk for both: twinrix vaccine.
For the sexually transmitted routes, condoms used every time lower risk, and barriers like dental dams reduce oral-anal exposure for hepatitis A. There's no vaccine for hepatitis C, so there prevention means never sharing needles, razors, or anything that contacts blood. Routine testing matters too, because these infections often cause no symptoms. You can carry hepatitis B or C for years feeling fine. If you're sexually active or have any risk factor, make screening part of your normal care and get tested: get tested.
How the risk profile compares
| Feature | Hepatitis A | Hepatitis B | Hepatitis C |
|---|---|---|---|
| Main route | Fecal-oral (incl. oral-anal sex) | Blood, semen, vaginal fluid | Blood (sharing needles) |
| Becomes chronic? | No — full recovery | Sometimes | Usually if untreated |
| Vaccine available? | Yes | Yes | No |
| Sexual transmission | Yes (oral-anal) | Efficient | Less common, blood-linked |
If you think you've been exposed
Don't guess. Exposure to any of these has a window before a test turns positive, and for hepatitis A and B there are post-exposure steps that work best when done promptly. Check the timing in our guide on when to test after exposure and arrange screening: when to test after exposure.
When to see a clinician
See a clinician if you notice yellowing of the skin or eyes (jaundice), dark urine, pale stools, persistent nausea, or right-sided belly pain — classic signs the liver is inflamed. Go promptly if you've had a known exposure, share injection equipment, or have a partner diagnosed with hepatitis B or C, even with no symptoms. Reported acute hepatitis A fell from nearly 10,000 cases in 2020 to about 1,600 in 2023 as the large person-to-person outbreaks waned CDC AtlasPlus, 2023, but cases still occur, and most people recover completely with no lasting liver damage when they get care. Clinics handle this daily.