What is Hepatitis B?
Hepatitis B screening for people at high risk, including people from countries with 2% or more Hepatitis B prevalence, and U.S.-born people not vaccinated as infants and with at least one parent born in a region with 8% or more Hepatitis B prevalence.
Hepatitis B: the hepatitis B screening test is called hepatitis B surface antigen. It detects a protein produced by the virus and can detect a hepatitis B infection even before it causes symptoms. If a woman who is considering getting pregnant tests positive for hepatitis B, she should talk to her healthcare practitioner about how long she should wait to allow the infection to resolve before becoming pregnant.
It is important to detect active hepatitis B infections in pregnant women because newborns are especially vulnerable to developing chronic infection; up to 90% of those who become infected with hepatitis B in utero will become carriers. If a hepatitis infection is detected in a pregnant woman, she can be monitored and the baby can receive treatment at birth to minimize the risk of it developing hepatitis B.
A negative test for the virus means either that there is no current infection or there is not yet a sufficient amount of the antigen to be detected. If a woman participates in high-risk activities that may transmit the hepatitis B virus (such as unprotected sexual contact or intravenous drug use), retesting later in the pregnancy is generally advised.
Approximately 700,000 to 2.2 million persons in the United States have chronic HBV infection 1–3. In the United States, persons considered at high risk for HBV infection include those from countries with a high prevalence of HBV infection, HIV-positive persons, injection drug users, household contacts of persons with HBV infection, and men who have sex with men 2.
The natural history of chronic HBV infection varies but can include the potential long-term sequelae of cirrhosis, hepatic decompensation, and hepatocellular carcinoma. An estimated 15% to 25% of persons with chronic HBV infection die of cirrhosis or hepatocellular carcinoma 2, 4. Those with chronic infection also serve as a reservoir for person-to-person transmission of HBV infection. Screening for HBV infection could identify chronically infected persons who may benefit from treatment or other interventions, such as surveillance for hepatocellular carcinoma.
Identification of chronic HBV infection based on serologic markers is considered accurate. Immunoassays for detecting hepatitis B surface antigen (HBsAg) have a reported sensitivity and specificity of greater than 98%.
HBV is a virus that infects the liver and is detected with a blood test. Long-term infection with HBV damages the liver and can lead to liver cancer, scarring of the liver called cirrhosis, liver failure, and even death. HBV is spread by coming into contact with body fluids, such as blood or semen, of a person who is infected.
HBV infection can be prevented with a three-shot vaccine series. Not all people with HBV infection need treatment for the infection, depending on the results of screening. Some may need regular testing to watch for a reactivation. Others may need treatment with drugs called antiviral medications to avoid reactivation.
Those at high risk for hepatitis B infection include:
- People who use injection drugs
- People with multiple sex partners or those diagnosed with a sexually transmitted disease
- Men who have sex with men
- People who have sexual contact with or live in the same household as someone who is already infected with HBV
- Infants who are born to mothers infected with HBV
- Infants and children of immigrants from areas with high rates of HBV infection, such as Eastern Europe, Asia, Africa, the Middle East, and the Pacific Islands
- Health care workers or other employees who come into contact with human blood
- Patients who are receiving hemodialysis for kidney disease
HBV and cancer
For people with cancer and HBV infection who need cancer treatment that lowers the immune system, there is a risk that an inactive, or latent, infection with hepatitis B can become active again. This is called reactivation, and it could lead to serious liver problems and complicate cancer treatment.
It is also not clear why some cancer treatments cause reactivation while others do not. Treatments that lower the immune system and have a high chance of leading to reactivation include the following:
- High-dose chemotherapy for a stem cell/bone marrow transplantation
- Treatments that lower the number of B cells, such as anti-CD20 therapy.
Recommendations for HBV screening and treatment
In the updated provisional clinical opinion, ASCO recommends the following:
- Right now, there is not enough scientific evidence to recommend screening every patient for HBV.
- Patients should receive HBV screening if they have a high risk of HBV infection or are going to receive a cancer treatment that increases the risk of HBV reactivation. These types of treatments include anti-CD20 therapy or stem cell/bone marrow transplantation.
- Testing should include two tests for HBV. One test looks for the hepatitis B surface antigen (HBsAg). The other test looks for the hepatitis B core antibody (anti-HBc). HBV reactivation can happen if both tests are positive or if only the anti-HBc test is positive.
Currently, there is no strong evidence to support either starting or stopping universal screening.
What this means for patients
Talk with your doctor about whether you need HBV testing given your health, risk factors for HBV infection, and cancer treatment plan. Having an HBV test and receiving antiviral therapy if you test positive can help you avoid HBV reactivation.
Patients who need antiviral medication may need to take it during cancer treatment and for six months to one year after cancer treatment. This additional treatment could add to the overall cost of treatment. In addition, patients receiving antiviral therapy may need to visit a hepatitis specialist. If you have a high risk of HBV and/or are going to receive cancer treatment that could reactivate the virus, talk with your doctor about HBV screening and any concerns you may have about managing your care.