A report has warned that drugs used to treat one type of hepatitis may be considered dangerous because of their capacity to trigger another type of the disease. The cure for hepatitis C may activate hepatitis B in people carrying both infections.

The European Medicines Agency said that medicines including Harvoni, Exviera, Daklinza, Olysio, Viekirax, Sovaldi, which are used to treat hepatitis C, may activate its latent counterpart. These drugs were found to be effective in treating 90 percent of individuals with infection.

"Cases of the return of previously inactive hepatitis B infection, which can be fatal, have been reported in patients treated," the report said. Meanwhile, the Pharmacovigilance Risk Assessment Committee (PRAC) has noted that the activation of hepatitis B may be linked to a reduction of its counterpart as the latter can suppress the other virus.

The report said that there have been approximately 30 cases of the activation of hepatitis B out of thousands of individuals prescribed with hepatitis C (HCV) drugs. To prevent cancer risks, the agency encouraged all individuals to have themselves tested for hepatitis B (HBV) before taking the aforementioned drugs. Manufacturers have also been instructed to add a warning on the information leaflets sold alongside their drugs. 

Hepatitis is a condition that results in the inflammation of the liver. HBV is acquired when a person comes in contact with the body fluids of an infected individual, including semen and blood. It can also be transmitted by mothers to their child during birth. Individuals exposed to patients are also at risk of acquiring the infection through contaminated injections or transfusion of contaminated blood. Meanwhile, HCV is usually acquired through contact with infected blood. There is also a possibility of sexual transmission although it is not common. There is currently no vaccine for hepatitis C.

The activation of hepatitis B by hepatitis C drug needs to be confirmed through further studies.