People take part in clinical trials for several reasons. Some people do so in order to get a new and otherwise unavailable treatment. Some people participate in order to get free laboratory tests. Also, one of the most common reasons is that participation helps scientists find better treatments for viral hepatitis.
Conversely, there may be reasons not to participate in a clinical trial. For instance, the treatments in the trial may have side effects or be unsafe. Other treatments you may want to take in the future may not work as well because of drugs you took in a clinical trial. Studies may also require hospital stays or invasive tests or procedures. Or you may just not have the time and energy that a study might require.