Hepatitis B is an infection of the liver caused by the hepatitis B virus (HBV). It can be acute and resolve without treatment. However, some forms can be chronic, and these could lead to cirrhosis and liver cancer.

HBV is a major global health concern. In fact, in 2015, HBV-related liver disease caused around 887,000 deaths worldwide.

As of 2016, the Centers for Disease Control and Prevention (CDC) estimate that 862,000 people in the United States are living with a chronic HBV infection.

For most adults, HBV is a short term condition that causes no permanent damage. However, 2–6% of adults with HBV go on to develop a chronic infection that can potentially lead to liver cancer.

Around 90% of infants with the virus will develop a chronic infection.

In this article, learn more about HBV, including transmission, early symptoms, and treatment.

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Sometimes, acute hepatitis B can resolve without treatment.

HBV can cause infection and inflammation of the liver. A person can have HBV and transmit the virus to others without knowing that they have it.

Some people experience no symptoms. Some only have the initial infection, which then resolves. For others, the condition becomes chronic. In chronic cases, the virus continues to attack the liver over time without detection, resulting in irreversible liver damage.

In 2017, 3,407 people reported an HBV infection to the CDC. However, accounting for people who do not report that they have the infection, the number of acute HBV infections may have been closer to 22,100.

Many HBV infections occur during infancy or childhood. This is because a mother can pass HBV to her child during childbirth. However, doctors rarely diagnose HBV in childhood, as it causes few obvious symptoms.

Symptoms of a new HBV infection may not be apparent in children under 5 years of age or in adults with a suppressed immune system. Among those aged 5 years and over, around 30–50% will show initial signs and symptoms.

Acute symptoms appear around 60–150 days after exposure to the virus, and they can last from several weeks to 6 months.

A person with a chronic HBV infection may have ongoing episodes of abdominal pain, persistent fatigue, and aching joints.

Early symptoms

If HBV does cause symptoms early on, they may include:

  • fever
  • joint pain
  • fatigue
  • nausea
  • vomiting
  • loss of appetite
  • abdominal pain
  • dark urine
  • clay colored stools
  • jaundice, or yellowing of the skin and whites of the eyes

HBV is transmissible when blood, semen, or another bodily fluid from a person with the virus enters the body of an individual who does not have it.

More specifically, infection can occur:

  • when a woman with HBV gives birth
  • during sexual activity
  • as a result of sharing needles, syringes, or other drug injection devices
  • as a result of practicing unsafe tattoo techniques
  • by sharing personal hygiene items, such as razors and toothbrushes

Health workers may be at risk through unsafe medical practices, such as reusing medical equipment, not using personal protection, or incorrectly disposing of sharps.

HBV cannot spread through:

  • food or water
  • shared eating utensils
  • breastfeeding
  • hugging
  • kissing
  • holding hands
  • coughing
  • sneezing
  • insect bites

The virus can survive outside the body for at least 7 days. During this time, it can still cause infection if it enters the body of a person who has not received vaccination against it.

There is currently no cure for HBV, but receiving the vaccine can prevent initial infection.

Antiviral medication can treat chronic infections. If chronic HBV starts causing permanent liver damage, undergoing a liver transplant can help improve long term survival.

However, receiving an effective vaccine and taking antiviral medications means that fewer people may end up needing a liver transplant as a result of chronic HBV.

There is no specific treatment, cure, or medication for an acute HBV infection. Supportive care will depend on the symptoms.

Treatment for suspected exposure

Anyone who has had potential exposure to HBV can undergo a postexposure "prophylaxis" protocol.

This consists of HBV vaccination and hepatitis B immunoglobin (HBIG). Healthcare workers give the prophylaxis after the exposure and before an acute infection develops.

This protocol will not cure an infection that has already developed. However, it decreases the rate of acute infection.

Treatment for chronic HBV infection

For chronic HBV infection, antiviral medications are available.

This is not a cure for chronic HBV. However, it can stop the virus from replicating and prevent its progression into advanced liver disease.

A person with a chronic HBV infection can develop cirrhosis or liver cancer rapidly and without warning. If a person does not have access to adequate treatment or facilities, liver cancer can be fatal within months of diagnosis.

People with a chronic HBV infection require ongoing medical evaluation and an ultrasound of the liver every 6–12 months. This monitoring can help doctors determine if liver damage is progressing or the condition is getting worse.

The cause of HBV is the hepatitis B virus infecting the body.

The virus occurs in the blood and bodily fluids. HBV is transmissible via semen, vaginal fluids, and blood. It can also pass from a mother to a newborn child during delivery. Sharing needles and having sex without contraception both increase the risk.

People can also contract HBV when they visit a part of the world in which infection is more common.

A person can spread the virus without being aware, as it may not cause any symptoms.

Screening is available for people at higher risk of an HBV infection or complications due to an undiagnosed HBV infection. If a person has HBV, the doctor may assess their liver for damage.

Hepatitis B test

A blood test can help a doctor diagnose acute and chronic HBV infection.

If the test confirms the presence of HBV, the doctor may request follow-up blood tests to confirm:

  • whether HBV infection is in its acute or chronic stage
  • the person's risk of liver damage
  • whether or not treatment is necessary

A doctor will recommend regular testing for people with chronic HBV. Once the condition reaches a chronic stage, it can change over time.

Hepatitis has many different types. HBV and the hepatitis C virus (HCV) have both acute and chronic forms.

The main difference between HBV and HCV is how they spread from person to person. Although HCV is transmissible via sexual activity, this is rare. HCV usually spreads when blood that carries the virus comes into contact with blood that does not.

Here, learn more about the differences between HBV and HCV.

If a woman with HBV becomes pregnant, they may transmit the virus to their baby. Women should inform the doctor who delivers their baby that they have HBV.

The infant should receive an HBV vaccine and HBIG with 12–24 hours of birth. This significantly reduces the risk that they will develop HBV.

The HBV vaccine is safe to receive while pregnant.

People with a high risk of HBV include:

  • the infants of mothers with HBV
  • the sexual partners of people with HBV
  • people who engage in sexual intercourse without contraception and those who have multiple sexual partners
  • men who have sex with men
  • people who inject illicit drugs
  • those who share a household with a person who has a chronic HBV infection
  • healthcare and public safety workers who are at risk of occupational exposure to blood or contaminated bodily fluids
  • people receiving hemodialysis, which is a type of kidney treatment
  • people taking medications that suppress the immune system, such as chemotherapy for cancer
  • people with HIV
  • those who come from a region with a high incidence of HBV
  • all women during pregnancy

People can prevent HBV infection by:

  • wearing appropriate protective equipment when working in healthcare settings or dealing with medical emergencies
  • not sharing needles
  • following safe sexual practices
  • cleaning any blood spills or dried blood with gloved hands using a 1:10 dilution of one part household bleach to 10 parts water

A vaccine against HBV has been available since 1982.

People who should receive this vaccine include:

  • all infants, children, and adolescents without a previous vaccination
  • all healthcare workers
  • those who may have had exposure to blood and blood products through work or treatment
  • people undergoing dialysis and the recipients of solid organ transplants
  • residents and staff of correctional facilities, halfway houses, and community residences
  • those who inject drugs
  • people who share a household or engage in sexual intercourse with someone who has a chronic HBV infection
  • those with multiple sexual partners
  • people who travel to countries where HBV is common

Schedule

The HBV vaccine takes the form of three injections. A person can receive the first injection at any age, but babies should receive the first injection soon after birth. The second shot should occur at least 1 month after the first.

Adults can receive the third dose at least 8 weeks after the second dose and 16 weeks after the first. Infants should not receive the third dose before 24 weeks of age.

Learn more about the benefits of the hepatitis B vaccine for newborns here.

How long does it last?

According to the World Health Organization (WHO), "the complete vaccine series induces protective antibody levels" in over 95% of the infants, children, and adolescents who receive it.

Immune memory induced by the HBV vaccine can last for at least 30 years in healthy people. That said, studies into the duration of the protection that the vaccine offers are ongoing.

Side effects

Many people tolerate the HBV vaccine well.

According to the CDC, the most common side effects of the HBV vaccine are fever and soreness at the injection site. A person may also experience swelling, redness, and hard skin in this area.

Very rarely, HBV vaccination can induce a serious type of allergic reaction called anaphylaxis.

Learn more about the possible effects of the HBV vaccine here.

Is it live?

The HBV vaccine contains no live virus. This makes it safe for women to receive during pregnancy and lactation.

HBV infections can cause a range of life threatening complications, including:

  • Cirrhosis. This causes scarring on the liver and inhibits liver functions. It can lead to liver failure.
  • Liver failure. Also known as end stage liver disease, this can progress either rapidly or over a longer period. The liver cannot replace damaged cells or function.
  • Liver cancer. Chronic HPV increases the risk of liver cancer.

Although HBV is a significant health concern around the world, for most people, the vaccine offers effective protection against the virus.

Q:

What is the most dangerous type of hepatitis?

A:

There are five types of viral hepatitis: hepatitis A through hepatitis E. All of these are dangerous in that they can potentially cause liver damage.

Some types, including hepatitis A and E, cause predominantly short term infections that the immune system will eventually clear. Others types, such as hepatitis B, C, and D, can cause both acute and chronic infections.

In chronic hepatitis, the immune system cannot clear the virus, so it can continue to cause liver damage. This can lead to serious complications, such as cirrhosis, liver failure, and even liver cancer.

To prevent potentially dangerous illnesses or complications from any type of hepatitis, be sure to practice proper preventative measures and receive hepatitis vaccinations, which are available for hepatitis A and B.

Jill Seladi-Schulman, PhD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.