What Is Hepatitis B?
Hepatitis B is the most common serious liver infection in the world. It is caused by the hepatitis B virus that damages the liver. Two billion people (or 1 in 3) have been infected and more than 240 million people are living with a chronic hepatitis B infection. Each year up to 1 million people die from hepatitis B despite the fact that it is preventable and treatable.
The hepatitis B virus (HBV) is transmitted through blood and infected bodily fluids. It can be passed to others through direct contact with blood, unprotected sex, use of illegal drugs, unsterilized or contaminated needles, and from an infected woman to her newborn during pregnancy or childbirth.
Hepatitis B is a “silent epidemic” because most people do not show symptoms when they are newly infected or chronically infected. Thus, they can unknowingly spread the virus to others and continue the silent spread of hepatitis B. For people who are chronically infected but don’t show any symptoms, their livers are silently damaged and this later manifests inn form of serious liver diseases such as cirrhosis or liver cancer.
The good news is that hepatitis B is preventable and treatable. There is a simple blood test to diagnose a hepatitis B infection. Testing is the only way to know for sure if you are infected. There is a safe vaccine to prevent hepatitis B. There are effective drug therapies that can manage a chronic hepatitis B infection and a cure is within sight.
Hepatitis B and The Liver
The liver is a vital organ in that we can survive only one or two days if it completely shuts down - once the liver fails, the body fails too. Fortunately, the liver can function even when up to 80% of it is diseased or removed. This is because it has the amazing ability to regenerate - or recreate - itself from healthy liver cells that still exist.
If the body were an automobile, the liver would be considered the engine. It performs several functions that ensure that the rest of the body functions properly. These functions include but are not limited to:
- Stores vitamins, sugar and iron to help give your body energy
- Controls the production and removal of cholesterol
- Clears the blood of waste products, drugs and other poisonous substances
- Makes clotting factors to stop excessive bleeding after cuts or injuries
- Produces immune factors and removes bacteria from the bloodstream to combat infection
- Releases a substance called bile to help digest food and absorb important nutrients
The word “hepatitis” actually means inflammation of the liver. Thus, hepatitis B refers to inflammation of the liver caused by the hepatitis B virus. With early detection and appropriate follow-up medical care, people living with a chronic hepatitis B infection can expect to enjoy a long and healthy life.
About the Hepatitis B Virus
The hepatitis B virus is a DNA virus that belongs to the “Hepadnaviridae” family. Related viruses in this family are also found in woodchucks, ground squirrels, tree squirrels, Peking ducks, and herons.
Structure of the Hepatitis B Virus
The hepatitis B virus contains an outer envelope and an inner core.
The outer envelope of the virus is composed of a surface protein called the hepatitis B surface antigen or "HBsAg". The HBsAg can be detected by a simple blood test and a positive test result indicates a person is infected with the hepatitis B virus.
The inner core of the virus is a protein shell referred to as the hepatitis B core antigen or "HBcAg," which contains the hepatitis B virus DNA and enzymes used in viral replication.
Life Cycle of the Hepatitis B Virus
The hepatitis B virus (HBV) has a complex life cycle. The virus enters the host liver cell and is transported into the nucleus of the liver cell. Once inside the nucleus, the viral DNA is transformed into a covalently closed circular DNA (cccDNA), which serves as a template for viral replication (creation of new hepatitis B virus). New HBV virus is packaged and leaves the liver cell, with the stable viral cccDNA remaining in the nucleus where it can integrate into the DNA of the host liver cell, as well as continue to create new hepatitis B virus. Although the life cycle is not completely understood, parts of this replicative process are error prone, which accounts for different genotypes or “genetic codes” of the hepatitis B virus.
Facts and Figures
- Hepatitis B is a global public health threat and the world’s most common serious liver infection. It is up to 100 times more infectious than the HIV/AIDS virus. It is also the primary cause of liver cancer (also known as hepatocellular carcinoma or HCC), which is the 2nd leading cause of cancer deaths in the world. One million people die each year from hepatitis B and related diseases.
- 2 billion people have been infected with the hepatitis B virus (1 out of 3 people)
- 10-30 million people will become newly infected each year
- 240 million people are chronically infected
- 1 million people die each year from hepatitis B and related complications such as liver cancer
- Approximately 2 people die each minute from hepatitis B
Hepatitis B is called a silent infection because most people do not show any symptoms when they are first infected. Thus, they can unknowingly pass the virus to others and continue the silent spread of hepatitis B. Testing is the only way to know for sure if you are infected.
Most healthy adults do not experience any symptoms when they are first infected with the hepatitis B virus
Some people who are infected will have symptoms and seek medical attention, but many will think they just have the flu and ignore the symptoms
About 1 percent of those infected will develop a life-threatening condition called fulminant hepatitis, which can be fatal and result in liver failure and death. Although this response is rare, fulminant hepatitis develops suddenly and requires immediate medical attention.
Common signs and symptoms of hepatitis B infection:
- Fever, fatigue, muscle or joint pain
- Loss of appetite
- Mild nausea and vomiting
- Stomach pain
- Pale or light colored stools
- Dark, tea colored urine
- Serious symptoms that require immediate medical attention
- Severe nausea and vomiting
- Yellow eyes and skin (called jaundice)
- Bloated or swollen stomach
It is always a good idea to talk to health care provider or seek medical attention if one doesn’t feel well or if they are uncertain about whether they have been infected with hepatitis B. A simple hepatitis B blood test can easily diagnose whether or not they have an infection.
The hepatitis B virus is transmitted through blood and bodily fluids. This can most commonly occur in the following ways:
- Direct contact with infected blood
- Unprotected sex
- Use of illegal or “street” drugs
- Needles that are contaminated or not sterilized
- From an infected woman to her newborn during pregnancy and childbirth
Body piercing, tattooing, acupuncture and even nail salons are other potential routes of infection unless sterilized needles and equipment are used. In addition, sharing sharp instruments such as razors, toothbrushes, nail clippers, earrings and body jewelry can be a source of infection.
Hepatitis B is NOT transmitted casually. It cannot be spread through toilet seats, doorknobs, sneezing, coughing, hugging or eating meals with someone who is infected with hepatitis B.
The hepatitis B virus can infect infants, children, teens and adults. It is not a genetic disease – it is an infectious disease that is transmitted through blood. Although everyone may be at risk for a hepatitis B infection during their lifetime, there are groups of people who are at higher risk because of where they were born, their occupation or life choices.
The following is a guide for screening high-risk groups for hepatitis B, but the list certainly doesn't represent all potential risk factors.
- Health care providers and emergency responders
- Sexually active individuals (more than 1 partner in the past six months)
- Men who have sex with men
- Individuals diagnosed with a sexually transmitted disease
- Illicit drug users (injecting, inhaling, snorting, pill popping)
- Sexual partners or those living in close household contact with an infected person
- Individuals born in countries where hepatitis B is common (Asia, Africa, South America, Pacific Islands, Eastern Europe, and the Middle East)
- Individuals born to parents who have emigrated from countries where hepatitis B is common
- Children adopted from countries where hepatitis B is common
- Adoptive families of children from countries where hepatitis B is common
- Kidney dialysis patients and those in early kidney (renal) failure
- Inmates and staff of a correctional facility
- Residents and staff of facilities for developmentally disabled persons
- ALL pregnant women