If some of these candidate vaccines make it to large-scale clinical trials, scientists will then face the next hurdle: how to test them on the general population. Because HCV prevalence is low in the U.S., testing a vaccine's ability to prevent infection would probably require thousands of U.S. volunteers or conducting the trial in high-incidence areas such as China, India or Egypt. Liang says that many groups involved in HCV vaccine development will probably first test their vaccine as a therapeutic vaccine to cure people chronically infected with HCV.
Even if one of the vaccine candidates is a success, it could take years to demonstrate its effectiveness, leaving time for the anti-HCV drugs to finish moving through the development-to-market pipeline. Alamo's Lawitz predicts that "in 2011 three drugs will be the standard treatment [for HCV]." The addition of telaprevir and other pending anti-HCV drugs to the armory would make the treatment of HCV more customized, similar to how antiretroviral treatment has become for HIV.
McHutchison hopes that by early 2010, people who are diagnosed with HCV will be tested to see which mutations they possess in the immune genes that predict response to interferon and ribavirin treatment. The people who bear the least likelihood of responding to the current treatment, those of African-American descent, may want to hold off for more promising treatments like telaprevir. On the flip side, "if you're genetically predisposed to have [a higher] chance, maybe you only need eight to 12 weeks [on therapy]," McHutchison says.
He adds, "To be able to go from saying [to a patient that you have a 40 percent chance of clearing the virus] to sitting down and saying that we're going to have to treat you for six months and you have a two-thirds chance is a very different conversation."