Hepatitis B

Hepatitis B is a viral infection that causes inflammation of the liver and can lead to both acute and chronic disease. CDC estimates that approximately 640,000 people in the United States have chronic, or long-term, hepatitis B. While many people associate hepatitis B with severe symptoms, the reality is often different. Many people with hepatitis B do not have any symptoms, which is why the condition can go undiagnosed for years.

Most adults who get HBV infections have acute infections and recover fully, even if their symptoms are severe. However, the younger someone is when they get hepatitis B, the higher their risk of the condition becoming chronic, which is especially true for newborns or children younger than 5. Approximately 90% of infected infants and 30% of children infected between 1–5 years will remain chronically infected with HBV, while approximately 95% of infected adults recover completely from acute HBV infection. For those with chronic hepatitis B, the condition requires ongoing monitoring and may need treatment to prevent serious complications.

Hepatitis B is primarily spread when blood, semen, or certain other body fluids – even in microscopic amounts – from a person infected with HBV enter the body of someone who is not infected. The most common ways hepatitis B spreads include sexual contact, sharing needles or syringes, and transmission from mother to child at birth. In the United States, injection drug use is the most common risk factor among people with new HBV infections, followed by having multiple sexual partners.

Other risk factors may include living with someone who has hepatitis B, being born in countries where hepatitis B is common, working in healthcare settings with blood exposure, men who have sex with men, people on dialysis, and those with certain medical conditions like HIV. The virus can also be transmitted through exposure to infected blood on personal items like toothbrushes or razors. People with diabetes have higher rates of hepatitis B and may be at increased risk through sharing blood glucose meters, fingerstick devices, or other equipment.

CDC recommends all adults get screened for hepatitis B at least once in their lifetime through a blood test. Testing becomes particularly important if someone has risk factors such as a history of injection drug use, multiple sexual partners, being born in areas where hepatitis B is common, or having close contact with someone who has hepatitis B. Anyone who knows they've been exposed to the hepatitis B virus should contact a healthcare professional right away, as preventive treatment may lower the risk of infection if received within 24 hours of exposure.

Symptoms of acute hepatitis B, when present, appear an average of 90 days after exposure but can range from 60–150 days. Since many people with hepatitis B don't experience symptoms, regular testing is the only reliable way to know your status. Testing may also be recommended for pregnant individuals, healthcare workers, and anyone planning travel to areas where hepatitis B is more common.

A positive or reactive HBsAg test result indicates that a person is infected with hepatitis B. If someone tests positive, further testing may be needed to determine if this is a new acute infection or a chronic hepatitis B infection. A negative HBsAg result generally means no current hepatitis B infection, though there can be a "window period" early after exposure when the test might not yet detect the virus.

Liver function test results can help assess whether hepatitis B is affecting liver health. Some people develop chronic hepatitis with elevated liver enzymes, cirrhosis, or hepatocellular carcinoma (primary liver cancer), while others may have no evidence of liver disease or injury. Elevated liver enzymes might suggest active liver inflammation, while normal results don't rule out hepatitis B infection. It's important to discuss all test results with a healthcare provider for proper interpretation and to determine if additional testing or monitoring is needed.

Prevention remains the most effective approach to hepatitis B. Vaccination is highly effective and recommended for most people. For those with existing hepatitis B infections, certain lifestyle modifications can help protect liver health and reduce transmission risk. This includes avoiding alcohol, which can worsen liver damage, eating a healthy diet, and avoiding sharing personal items that might have blood on them like razors or toothbrushes.

For sexually active individuals, practicing safe sex and ensuring partners are tested and vaccinated can help prevent transmission. Those who inject drugs should use clean needles and equipment. Regular medical monitoring is important for people with chronic hepatitis B to watch for complications and determine if antiviral treatment is needed.