Hi CNN,
Joan is absolutely correct that in HCV once daily oral therapy with the latest generation DAAs for 8-12 weeks does lead to a sustained virologic response (SVR) of HCV infection (no detectable HCV RNA in the absence of therapy) from which relapse is very rare (< 1% relapse rate 5 years after therapy). However, the term “cure” is still debated in the field since what we are really trying to “cure” by treatment is not the viral infection itself but the underlying liver disease. For HCV, the there is a clear improvement in liver disease in HCV following successful treatment but many persons achieving SVR still have progression of liver disease and or HCC, particularly if they had advanced liver disease before therapy. These issues are still evolving in the field today. Also HCV “cure” does not protect you from getting infected again.
A good reference on this is https://www.hepatitisc.uw.edu/pdf/evaluation-treatment/treatment-goals-predicting-response/core-concept/all.
For functional cure of HBV, HBsAg loss means that integrated HBV DNA has been removed from the liver (the cause of HBV-mediated HCC) and cccDNA is silent (which is the source of the bulk of inflammatory driven fibrosis and cirrhosis). Thus the functional cure of HBV is actually a better cure of overall liver disease in HBV than SVR is with HCV, with very low rates of HCC and reversal of fibrosis even when this advanced liver disease is pre-existing before treatment. Also the immune control which comes with functional cure of HBV will protect you from future HBV infection.