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This article waslast modified on July 10, 2017.

All patients diagnosed with hepatitis C and starting treatment with direct-acting antiviral (DAA) drugs should be tested for hepatitis B co-infection, advises the U.S. Food and Drug Administration (FDA). Co-infected patients require monitoring during treatment and post-treatment to make sure their hepatitis B infection doesn't worsen when their hepatitis C infection is treated. The American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) issued similar recommendations in a recently released update to their HCV Guidance.

In the U.S., about 1.4% of people who are infected with hepatitis C virus (HCV) are also infected with hepatitis B virus (HBV). Like HCV, HBV infects and damages the liver and is spread through contact with blood or body fluids from an infected person. Some people with chronic HBV infection remain symptom-free and may not know they are infected.

HCV can be treated with DAAs to prevent progression of liver disease, to reduce symptoms, and to clear HCV from the body. These drugs have greatly improved the cure rate of HCV compared to older therapies. In people co-infected with HBV, the hepatitis B viral load can be low, while HCV is actively multiplying and damaging the liver. When hepatitis C is treated with DAAs in co-infected individuals, HBV can reactivate and cause severe liver damage. In some cases, this can occur very quickly and lead to liver failure and death.

To increase awareness of this risk, the FDA has issued a new safety warning. It is requiring a Boxed Warning—it's most prominent warning—about the risk of HBV reactivation to be added to the drug labels of DAAs. The Boxed Warning directs healthcare practitioners to screen and monitor for HBV in all patients receiving DAA treatment. This warning will also be included in the patient information leaflet or medication guides for DAA medicines. To view a list of drugs that will require a Boxed Warning, visit the FDA's Safety Announcement.

In their updated HCV guidance, the AASLD and IDSA recommend blood tests to detect HBV co-infection. (For details on these tests, see Hepatitis B Testing.) Patients who test positive and are not already receiving antiviral medications for hepatitis B should have their HBV viral DNA levels (viral load) monitored during and immediately after DAA therapy. HBV viral DNA tests detect hepatitis B viral genetic material in the blood. If the HBV viral load gets too high, patients may need to start treatment for hepatitis B.

Patients should tell their healthcare practitioners if they have a history of hepatitis B infection or other liver conditions before starting treatment for hepatitis C. They should report any side effects from their medications and contact their healthcare practitioner right away if they experience signs or symptoms that may indicate serious liver problems, such as fatigue, weakness, loss of appetite, nausea and vomiting or yellow eyes or skin (jaundice).

Those who have already started on DAA therapy for hepatitis C should not stop taking their medications without first talking to their healthcare provider. Stopping treatment early could result in the virus becoming less responsive to other hepatitis C treatments.


U.S. Department of Health and Human Services. FDA Drug Safety Communication: FDA warns about the risk of hepatitis B reactivating in some patients treated with direct-acting antivirals for hepatitis C. Available online at Accessed October 19, 2016.

American Association for the Study of Liver Disease and Infectious Diseases Society of America. HCV Guidance: Recommendations for Testing, Managing, and Treating Hepatitis C. Available online at Accessed October 18, 2016.

European Association for the Study of the Liver. EASL Recommendations on Treatment of Hepatitis C 2016. Journal of Hepatology. Article in press 2016: jhep.2016.09.001.

Mayo Clinic Staff. Hepatitis C Treatment. Available online at Accessed October 18, 2016.

DeMonte A, Courjon J, Anty R, et al. Direct-acting Antiviral Treatment in Adults Infected with Hepatitis C Virus: Reactivation of Hepatitis B Virus Coinfection as a Further Challenge. Journal of Clinical Virology. 2016;78:27-30.

Liu C. Treatment of Patients With Dual Hepatitis C Virus and Hepatitis B Virus Infection: Resolved and Unresolved Issues. Journal of Gastroenterology and Hepatology. 2014;29(1):26-30.