Hepatitis A, B and C are known as viral hepatitis, and that in itself is just one subcategory of the disorder. Hepatitis, which literally means inflammation of the liver, can occur in multiple other ways, including alcohol-related liver disease, metabolic-associated fatty liver disease and drug-induced liver injury. These are known as non-viral types of hepatitis and fatty liver disease (also known as non-alcoholic fatty liver disease) is the most common cause of chronic liver disease in the world, affecting one in every four people, according to research in the journal Hepatology. So there are viral and non-viral categories of hepatitis. Within the viral world, there are five common hepatitis types. Along with A, B and C, hepatitis D and E round out the picture. If you’ve never heard of hepatitis D or E, it might be because they are less common in the U.S. than in other parts of the world. Let’s take a look at each of these types—but first, let’s dive a little deeper into the nuts and bolts of this condition.

What Is Hepatitis?

In a nutshell, hepatitis means inflammation of the liver. This can happen due to excessive alcohol use, toxins in the environment, reaction to medications, certain other medical conditions or infection with a virus, according to the World Health Organization. In the case of viral hepatitis, once the virus makes its way to your liver, your immune system sounds the alarm, setting off a cascade of events. “The virus replicates within liver cells,” explains Dr. Norah Terrault, MD, a professor of medicine and chief of gastroenterology and liver diseases at the Keck School of Medicine at University of South California in Los Angeles. “The immune system recognizes that this is a foreign agent and attacks it to get rid of it. But in that effort, which is not usually successful, there is ongoing inflammation and injury to the liver itself.” That injury triggers the liver to start producing proteins known as collagen to repair the damage. But over time, an excess amount of collagen results in fibrosis—or scarring—of the liver, says Eugene R Schiff, M.D., the executive director of the Schiff Center for Liver Diseases at the University of Miami Health System. “On a microscopic level, you begin to lay down collagen in your liver at a rate that exceeds your body’s ability to break it down,” Dr. Schiff explains. Left unchecked, the scarring results in a condition known as cirrhosis, which prevents your liver from performing its normal role in your body. Though it’s not an organ you probably spend a whole lot of time thinking about, your liver is responsible for some important functions, including processing nutrients, filtering blood, removing waste and fighting infection, per the CDC. It’s the loss of those functions—technically caused by cirrhosis, not hepatitis—that most people picture when they think of symptoms of hepatitis A, B or C.

What Is Hepatitis A?

The term hepatitis A first came into the public sphere in 1947, as a way to distinguish it from hepatitis B after scientists established there were two different viruses that were responsible for causing similar physical symptoms in outbreaks that were occurring at that time. The hepatitis A virus causes a disease that is usually acute (meaning symptoms don’t last for more than a few months) and it’s typically transmitted through contaminated food or water. And the main thing to know: There’s a vaccine for it! “Most children are vaccinated for hepatitis A,” says Dr. Schiff. Still, the CDC estimates there are about 24,900 new cases of hepatitis A every year in the U.S, although most people recover without any lasting damage to their livers (in rare cases, however, hepatitis A can be deadly). There is currently no cure for hepatitis A, but a new study published just this month by researchers at the University of North Carolina School of Medicine in Chapel Hill found for the first time a drug that can halt the replication of the hepatitis A virus in the liver in lab studies, meaning in the distant future, a cure may be possible. (While exciting, this drug likely won’t be available for human use for several years.)

What Is Hepatitis B?

While the CDC puts the number of people living with hepatitis B in the U.S. at just under one million, other organizations like the Cleveland Clinic estimate that number to be significantly higher. Either way, hepatitis B is a serious, life-threatening disease that is transmitted largely through blood, semen and other bodily fluids. The virus can be asymptomatic in early stages, and for that reason, about two-thirds of people in the U.S. who have hepatitis B don’t know it. (About 50% of diagnosed cases are in the Asian American population.) Unlike hepatitis A, which frequently clears on its own, people who are infected with hepatitis B likely will go on to develop a chronic form of the disease. The good news? There is a vaccine for hepatitis B, which all children can receive.

What Is Hepatitis C?

Hepatitis C is a disease caused by a bloodborne virus that infects your liver. (If you’re wondering about the alphabet soup we have going, there’s no significance to the letters, it’s just the order in which scientists discovered the specific viruses that cause liver inflammation.) “In fact, until the exact virus causing it was identified in 1989, hepatitis C used to be referred to as ‘non-A, non-B hepatitis,”’ says hematologist Dr. Ype de Jong, MD, PhD, an assistant professor of medicine in gastroenterology and hepatology at Weill Cornell Medicine and NewYork-Presbyterian in New York City. Today, experts say hepatitis C affects between 2.5 and 4.7 million Americans, a wide spread that accounts for a large percent of the population who have been infected by the virus but do not know it, due to a lack of symptoms. (By the time symptoms appear with hepatitis C, it means cirrhosis of the liver has occurred.) There is no vaccine for C, but there are effective direct-acting antiviral drug treatments for it.

What Is Hepatitis D?

OK, so that’s A, B and C. As for D, there’s good news and there’s bad news. The good news is that you can’t contract hepatitis D unless you first get hepatitis B. The reason? “Delta [the name for hepatitis D] requires the covering or envelope of the B virus in order to get inside your liver cells and replicate,” explains Dr. de Jong. The bad news, then, is that if you are diagnosed with hepatitis D it means you likely also have B, even if you were unaware of the infection. Approximately 5 percent of people worldwide who have hepatitis B also have hepatitis D, according to the World Health Organization. Cases have been going down in recent years, as the number of people vaccinated for hepatitis B has increased. (Delta itself has no vaccine.) You can contract hepatitis D through contact with blood or bodily fluids from someone who has the virus.

What Is Hepatitis E?

Last but not least, hepatitis E is responsible for an estimated 20 million infections worldwide every year, but only slightly more than three million of those cases are likely to have symptoms, per the World Health Organization. As with hepatitis A, hepatitis E is generally transmitted through contaminated water and food. (Complicating matters, there are actually four subtypes of hepatitis E—two of which are found in humans and two of which are found in animals that can then infect humans.) The virus is what’s referred to as “self-limiting” and usually clears itself in the body within two to six weeks. There is no vaccine and no targeted medication for hepatitis E, and it is less common in the U.S. than other types.

Which Type of Hepatitis Can You Get From Food?

While hepatitis B, C and D cause infection through contact with bodily fluids including semen and blood (or just blood, in the case of hepatitis C), the viruses A and E are typically contracted by eating contaminated food or drinking contaminated water. Typically, that food or water supply has come in contact with the feces of an infected person—often through poor hygienic practices. In the case of hepatitis A, the virus may be spread when a family member who has hepatitis A prepares food for the family without washing his or her hands. Hepatitis E, on the other hand, is more likely to be transmitted when water comes in contact with the feces of someone who has the virus and the entire drinking supply for an area becomes contaminated. (This is more likely to occur in less-developed areas of the world.) It’s also possible to get hepatitis E from eating undercooked pork or other meat from animals that have been infected with the virus.

Which Hepatitis Is Curable?

To recap, hepatitis A and B have vaccines. Unvaccinated people who contract either of these viruses can be treated (and hepatitis A usually clears up on its own), but not cured. Hepatitis C, on the other hand, has no vaccine, but recent treatments for the virus, known as direct-acting antiviral medications, can cure people of the disease (i.e., remove all traces of the virus in their system) in around 95 percent of the cases. These medications include: Epclusa, Harvoni, Mavyret, Vosevi and Zepatier. The important thing to know, however, is that the cure is not permanent. If you go back to the same behaviors that caused you to contract hepatitis C in the first place (mainly, shared needles), you can get it again.

Which Hepatitis Is Not Curable?

If you are not vaccinated and contract hepatitis B, treatment can be a challenge. For some, the virus may clear after a few weeks or months without any medical intervention (known as acute hepatitis B). But many other people will go on to develop chronic hepatitis B, with or without symptoms (like all types of hepatitis, symptoms appear once the liver becomes impaired). There are medications to ease symptoms of hepatitis B, but not cure them, and because they may have side effects not everyone will be able to take them for the long term.

Which Hepatitis Is Worst?

Although you probably don’t want to be infected with any of these types of hepatitis, it’s the combination of the hepatitis B and D viruses that can do the greatest damage to your health. A rapid progression toward liver-related deaths and liver cancer make hepatitis B and D the most severe form of chronic viral hepatitis, according to the World Health Organization.

Which Hepatitis Has a Vaccine?

“The good news is that there is a vaccine for both hepatitis A and hepatitis B, and they are very effective,” says Dr. Schiff. The CDC recommends all infants and young children receive both of these vaccines. It is recommended that adults who were not vaccinated as children receive them if they are 59 years old or younger. There is also a combination A and B vaccine for adults, given as three separate doses over a six-month period.

Is Hepatitis an STD?

Hepatitis A, B and C are all capable of being transmitted through sexual activity, according to the CDC, although technically only hepatitis B can be transmitted through semen and vaginal fluids. (Hepatitis A and C can be transmitted during sex if there is contact with blood or feces of an infected person.) Vaccination against hepatitis A and B is your best bet for preventing infection from sex, but the use of condoms as barrier protection may also help in the case of hepatitis B.

Hepatitis A and E viruses are transmitted primarily through food or water that has been contaminated with the feces of a person infected with one of these viruses. Even the smallest amount of contamination can lead to a new infection, according to the World Health Organization. Inadequate sanitation in communities and poor personal hygiene contribute to the spread of these viruses, which are not blood-related.

Which Hepatitis Is Deadly?

According to the latest data available from the World Health Organization, roughly 1.5 million people worldwide contracted hepatitis B in 2019, and the same estimated number contracted hepatitis C. Meanwhile, about 820,000 people died from hepatitis B-related causes in 2019, while 290,000 deaths were attributed to hepatitis C-related causes. (Remember, hepatitis itself just means inflammation—it’s when the disease progresses to cirrhosis or liver cancer that it can turn deadly.) The lower number of hepatitis C deaths may be due to the highly effective medications that are now available to treat it. The most important thing for you to know is this: Viral hepatitis of any type does not need to be deadly. It is preventable and treatable, and you can—and should—get screened for it since symptoms usually don’t show up until things are getting serious with your liver. If you think you may have come in contact with an infected person, food or water supply, talk with your doctor about getting tested. The sooner you have an answer, the faster you can be on your way back to better health. Up next: Top Signs of Liver Cancer—Plus Everything You Need to Know About Screening and Treatment

Sources

Norah Terrault, M.D., professor of medicine and chief of gastroenterology and liver diseases at the Keck School of Medicine at University of South California in Los AngelesEugene R Schiff, M.D., executive director of the Schiff Center for Liver Diseases at the University of Miami Health SystemYpe de Jong, M.D., Ph.D., assistant professor of medicine in gastroenterology and hepatology at Weill Cornell Medicine and NewYork-Presbyterian in New York CityMedicine Today: “Nonviral Hepatitis: Common Causes and Their Management.”Hepatology: “Global Perspectives on Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis.”Centers for Disease Control and Prevention: “What Is Viral Hepatitis?”World Health Organization: “Hepatitis.”Antiviral Research: “A Historical Perspective on the Discovery and Elucidation of the Hepatitis B Virus.”Proceedings of the National Academy of Sciences: “The ZCCHC14/TENT4 complex is required for hepatitis A virus RNA synthesis.”Cleveland Clinic: “Hepatitis B: Symptoms, Causes, Tests and Treatment.”World Health Organization: “Hepatitis D.”National Institute of Diabetes and Digestive and Kidney Disorders: “Hepatitis D.”World Health Organization: “Hepatitis E.”Centers for Disease Control and Prevention: “Hepatitis B Questions and Answers for the Public.”Centers for Disease Control and Prevention: “Sexual Transmission and Viral Hepatitis.”Centers for Disease Control and Prevention: “Hepatitis B Virus (HBV) Infection.”World Health Organization: “Hepatitis A.”

World Health Organization: “Global Progress Report on HIV, Viral Hepatitis and Sexually Transmitted Infections, 2021.”