Periodically, someone mistakenly tells me that hepatitis C is not curable. Most of the time, they are happy to learn that hepatitis C can be cured. However, some people just want to hang on to what they believe is true, even if it is wrong. There are still people who believe that the earth is flat and that a man never walked on the moon. There is no sense in arguing with people over beliefs.
However, saying hepatitis C is curable is a little more complicated than saying the earth is round. First, the earth is always round, whereas hepatitis C is not always curable. Second, even when the hepatitis C virus is eliminated, some people still have liver disease. The virus may be gone, but they still have a liver disease. We call that virologically cured.
The scientific term for “cured” is SVR. When hepatitis C is undetectable in the blood for six or more months after treatment ends, we say that person had a sustained virological response to treatment or an SVR. Early studies repeatedly found that nearly 100% of the time, hepatitis C does not return once there is an SVR. (Mark Swain and colleagues, Sarah Maylin and colleagues)
SVR24 means that hepatitis C is gone 24 weeks after the treatment drugs were stopped. SVR12 means that the virus is gone 12 weeks after the treatment ended. Patients with an SVR12 are 98% likely to have an SVR24. Patients who do not have an SVR12 are 99% likely NOT to have an SVR24.
What about SVR4, in which hepatitis C is gone 4 weeks after treatment ended? A study by Chen and colleagues in the June 2013 Gastroenterology (Earlier Sustained Virologic Response End Points for Regulatory Approval and Dose Selection of Hepatitis C Therapies) found that patients with an SVR4 were 91% likely to have an SVR24. Patients who do not have an SVR4 are 98% likely NOT to have an SVR24.
So, if you are going through hepatitis C treatment, your viral loads during the post-treatment are important indicators. They may not be certain predictors of your treatment outcome, but they are good enough to give you a glimpse of your treatment outcome. If your viral load comes back negative, take comfort in the fact that new drugs are around the corner. If it is positive, have a quiet, preliminary celebration. Go dancing on the round earth.