for Veterans and the Public
Frequently Asked Questions
Q: What is the difference between "relapse" and "nonresponse?"
The goal of treating chronic hepatitis C is to completely clear the virus. This means that your "viral load" (the number of virus copies detected from your blood test) is zero or so low that the virus can't be detected with standard blood tests.
Without treatment, the hepatitis C virus in liver cells constantly makes copies of itself, and the virus ends up not just in liver cells but also in the bloodstream. Treatment is intended to completely stop reproduction of the virus so that it doesn't continue to enter the bloodstream or cause any more injury to liver cells.
Successful treatment results in a "sustained virological response." This means the virus becomes completely undetectable (the blood test cannot find any virus at all) before the treatment is finished, and it remains undetectable for 6 months after treatment is stopped.
A "relapse" means the viral load drops to an undetectable level before treatment is completed, but becomes detectable again within 6 months after treatment is stopped. Even if the virus returns at a level that is lower than it was before treatment, a relapse is still considered to have occurred. A relapse can be determined if the viral load starts to rise during treatment, or at any time after the virus becomes undetectable.
A "nonresponse" means the viral load never drops significantly and the virus remains detectable throughout the course of treatment.
A rapid response can occur as early as 4 weeks into treatment. However, a nonresponse is not determined until after 6 months of treatment. If the viral load has not dropped significantly or the virus has not become undetectable by that time, treatment probably would be stopped because it is very unlikely that a sustained virologic response could be achieved after that point.