Two hepatitis vaccines exist in the U.S. , one for hepatitis A and one for hepatitis B, plus Twinrix, a combined shot that covers both. There's no vaccine for hepatitis C. The CDC now recommends hepatitis B vaccination for all adults aged 19–59, and for older adults with risk factors.
At a glance
- Hepatitis A vaccine
- 2 doses
- 6–18 months apart
- Hepatitis B vaccine
- 2–3 doses
- >90% effective; lifelong protection
- Twinrix (A+B)
- 3 doses
- 0, 1, 6 months; combined option
- Hepatitis C
- no vaccine
- prevention + curable with DAAs instead
| Item | Value |
|---|---|
| Hepatitis A vaccine | 2 doses: 6–18 months apart |
| Hepatitis B vaccine | 2–3 doses: >90% effective; lifelong protection |
| Twinrix (A+B) | 3 doses: 0, 1, 6 months; combined option |
| Hepatitis C | no vaccine: prevention + curable with DAAs instead |
The hepatitis vaccines that exist (A and B), and why there's none for C
Three vaccine letters get conflated, and only two are vaccine-preventable. Hepatitis A and hepatitis B both have safe, long-tested vaccines. Hepatitis C has none, and that gap is a hard biological problem we'll get to below.
The two viruses spread differently, which is why the vaccines target different people. Hepatitis A is shed in stool and spreads through contaminated food, water, and close personal or sexual contact. Hepatitis B is blood-borne and sexually transmitted, moving when blood, semen, or other body fluids enter an uninfected person through sex, shared needles, or from parent to baby at birth. Hepatitis B does not spread through sneezing, hugging, sharing utensils, or food and water CDC.
Vaccination matters most for hepatitis B because the stakes change so sharply with age. Caught in adulthood, hepatitis B becomes a lifelong chronic infection in fewer than 5% of people. Caught at birth, about 90% of infants become chronically infected CDC. A vaccine up front sidesteps a disease that, once chronic, can be controlled but rarely cured. For the bigger picture on how these viruses behave silently, see our overview of hepatitis b and c.
Hepatitis B vaccine: schedule, who needs it, how effective
The hepatitis B vaccine is a recombinant shot. It contains a piece of the virus's surface protein (HBsAg) made in the lab, not live virus, so it can't give you hepatitis. Your immune system learns to recognize that protein and builds protective antibodies (anti-HBs). It's given as a series of injections in the upper arm over a span of months, depending on the product used.
In 2024, ACIP updated its guidance to recommend hepatitis B vaccination for all adults aged 19–59 years, and for adults 60 and older who have risk factors, and it remains the principal way to prevent HBV infection MMWR Updated Hepatitis B. Risk factors include sexual exposure, injection drug use, certain medical conditions, and occupational blood contact ACIP, but most adults under 60 simply qualify across the board now.
The vaccine is highly effective once you complete the series, and most people who finish it develop lasting immunity. After the full course, a blood test for anti-HBs can confirm you responded, which matters for healthcare workers and people with weakened immune systems.
If you've already been exposed to someone who is HBsAg-positive, the vaccine alone isn't enough. Post-exposure prophylaxis combines hepatitis B immune globulin (HBIG, ready-made antibodies) with the vaccine, given as soon as possible, ideally within 24 hours CDC. If you're worried about a recent exposure, our guide to when to test after exposure explains the timing.
Hepatitis A vaccine: schedule, who needs it
The hepatitis A vaccine is an inactivated (killed-virus) shot given as a series of injections over several months. Hepatitis A causes an acute liver illness and doesn't become chronic the way hepatitis B can, but it can make you sick for weeks and, rarely, cause liver failure.
It's routinely recommended for children and for adults with elevated risk: people traveling to areas where hepatitis A is common, men who have sex with men, people who use drugs, people experiencing homelessness, and those with chronic liver disease ACIP. Anyone who wants protection can ask for it even without a listed risk factor.
Outbreaks among gay and bisexual men have made this vaccine especially relevant in that community. We cover indications and access in detail in our piece on hep A & B vaccines for MSM.
Twinrix: the combined A+B option
Twinrix is a single vaccine that protects against both hepatitis A and hepatitis B. For an adult who needs both, a common situation, since the risk factors overlap heavily, it folds two series into one set of appointments, which means fewer total visits and shots.
It's an option, not a requirement. If you've already completed one series, say you got hepatitis B as an infant, you'd typically just get the single missing vaccine rather than the combined one. A clinician can check your records and figure out the cleanest path.
| Vaccine | Protects against | Becomes chronic? | Typically recommended for |
|---|---|---|---|
| Hepatitis A vaccine | Hepatitis A only | No: acute illness only | Children, travelers, MSM, drug use, chronic liver disease |
| Hepatitis B vaccine | Hepatitis B only | Yes, can be lifelong | All adults 19–59; newborns; adults 60+ with risk factors |
| Twinrix | Hepatitis A + B | , | Adults who need both series |
| Hepatitis C | No vaccine exists | Yes, but curable | Prevention via testing & harm reduction |
Why hepatitis C has no vaccine (and what to do instead)
Hepatitis C is the virus people most often ask about, and the one with no shot. The virus mutates rapidly and exists as many different genetic variants, so the immune system struggles to mount a single response that covers them all. Decades of research haven't yet produced a vaccine that holds up against that variability.
There's a real upside. Unlike chronic hepatitis B, which is controlled but rarely cured, hepatitis C is now curable in most people with a short course of oral antiviral pills CDC. The strategy shifted from prevention-by-vaccine to find-and-treat: routine screening identifies infections, and treatment clears the virus.
Until a vaccine exists, prevention for hepatitis C, and a backstop for hepatitis B, comes down to the basics. Don't share needles or injection equipment, use condoms every time, and test routinely, because these infections often have no symptoms. You can get tested for the bloodborne infections through a clinic or an at-home option.
Catch-up and adult vaccination
Plenty of adults missed these vaccines as kids, since the universal infant hepatitis B program is relatively recent and hepatitis A wasn't routine for a long time. Catch-up is straightforward: you don't restart a series you partly completed years ago, you simply finish it. There's no maximum interval that forces you to begin again.
For hepatitis B specifically, the 2024 universal recommendation for adults 19–59 means most people no longer have to justify why they want it; it's the default. Pair vaccination with knowing your status. The CDC recommends every adult 18 and older be screened for hepatitis B at least once in their lifetime, using a panel that checks for active infection, immunity, and past exposure CDC, 2023. Vaccinating someone already immune does no harm, but screening tells you where you actually stand.
When to talk to a clinician
Bring it up at a routine visit if you've never been vaccinated against hepatitis A or B, if you're unsure of your childhood records, or if you've had a possible exposure. Time-sensitive situations, a needlestick, sex with someone who has hepatitis B, or a planned trip to a high-risk area, warrant a same-week call rather than waiting.
Pregnancy is its own conversation. Every pregnancy is screened for hepatitis B because the virus can pass to the baby at birth, and newborn prophylaxis prevents most of that transmission. We cover that fully in our guide to hepatitis and pregnancy.
A hepatitis diagnosis is common and manageable. Clinics handle it daily, and it says nothing about you as a person.
Keep exploring on EasySTD: your risk of an STD, STD vaccines and Hepatitis A testing.