Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). The virus spreads from person to person through bodily fluids, including blood or semen. Hepatitis B can be acute or chronic.

Acute hepatitis B may have no symptoms or may present with symptoms that develop into jaundice. This can progress to chronic hepatitis B if the virus doesn't clear after 6 months.

Chronic hepatitis B lasts for at least 6 months. People with this type of hepatitis can carry the virus for life. In some cases, chronic hepatitis B develops from the acute form.

Most people with acute hepatitis B recover fully. Some may not experience any symptoms. Conversely, people with chronic hepatitis B often require treatment to manage the infection. Chronic hepatitis B also increases the risk of cirrhosis and certain types of liver cancer.

The risk of developing chronic hepatitis B depends on when the virus is diagnosed. Children with hepatitis B, especially those under 5 years old, have a higher risk of developing the chronic form. Adults are less likely to develop chronic hepatitis B. The virus can remain dormant for years before symptoms appear.

Hepatitis B is often spread through sexual contact, sharing needles, and accidental needlesticks. While there's no cure, the disease is preventable through several measures:

Use condoms or other protective measures during sex.

Get tested for hepatitis B regularly.

Don't share personal items that may be contaminated with blood, such as razors or toothbrushes.

Don't share needles or syringes.

Get the hepatitis B vaccine. This is one of the most effective ways to prevent hepatitis B. The vaccine is usually given in three doses, and in many countries, newborns receive their first dose at birth.

The US Centers for Disease Control and Prevention (CDC) recommends that newborns receive their first dose of the vaccine at birth and complete all doses between 6 and 18 months of age.

At-risk adults should also receive the hepatitis B vaccine. This includes individuals who:

Travel to or live in areas where hepatitis B is common.

Have sex with more than one partner or with a partner who has hepatitis B.

Work in healthcare or other settings with frequent exposure to bodily fluids.

Use intravenous drugs and share injection equipment.

Have chronic liver disease, human immunodeficiency virus (HIV) infection, hepatitis C infection, diabetes, or kidney disease requiring dialysis.

If you've been exposed to the hepatitis B virus and haven't been vaccinated, seek immediate medical attention for testing. Based on the test results, your doctor may administer the first dose of the vaccine and schedule follow-up doses.

Your doctor may also prescribe a medication called hepatitis B immunoglobulin. This medication provides rapid protection against the virus for short-term defense. Both options are most effective when started as soon as possible after exposure.

Bao Bao (Healthline)