Hepatitis C Virus Vaccines in the Era of New Direct-acting Antivirals

Chao Shi; Alexander Ploss

Disclosures

Expert Rev Gastroenterol Hepatol. 2013;7(2):171-185. 

In This Article

Unmet Demands

First, access to the new drugs is limited due to their high costs. Depending on the duration of treatment, a regimen of telaprevir or boceprevir costs US$30,000–50,000.[15] According to the current paradigms, peg-IFN/RBV, which costs $35,000 per course, still needs to be added to the treatment with either DAAs. Meanwhile, additional expenses for managing the side effects, among which are anemia, rash and depression, must be considered. Because HCV infection is prevalent among marginalized groups with lower incomes, who usually lack adequate coverage by medical insurance, the penetration of new treatment will probably be low. Moreover, since most new incidences of HCV infection in the USA are acquired through sharing of contaminated needles or syringes by IDUs, a low penetrance of treatment in this population will keep the number of new infections at a sustained level. Even if a certain rate of treatment can be achieved in the high-risk population of IDUs, frequent re-exposure and reinfection can still pose a problem, but may be ameliorated if an at least partially protective vaccine were available. Therefore, hepatitis C may become more of a social problem than a medical one. This critical issue will be difficult to tackle without sufficient political support.

Second, although HCV drug development is moving forward rapidly, the efforts to identify chronic HCV carriers lag behind. As 80% of people do not exhibit any symptoms following initial infection, most people with HCV are unaware of their infection status.[16] This is especially a problem for the high-risk population, which do not have access to routine medical screening. The low rate of diagnosis not only leads to an underestimation of overall HCV burden, but also limits the utilization of effective treatments.

Third, HCV infection will remain a global epidemic in the foreseeable future. Even if it will be possible to treat all the infected individuals in developed countries with new DAA regimens, HCV infection is likely to persist in the vast majority who live in the developing world, where the medical infrastructure cannot support and afford the treatment. Those developing countries also face the additional challenge of a high transmission rate owing to inadequate screening of blood products and an increasing number of IDUs.[17] Given the constant human migration, it is impossible for the developed countries to insulate themselves from the epidemic elsewhere. Furthermore, as most new drugs were designed to treat HCV genotype 1, because it is difficult to cure with peg-IFN/RBV, and it is predominant in developed counties, the effectiveness of those drugs for controlling infection with other genotypes remains to be tested. This is particularly problematic as nongenotype 1 viruses are widely distributed around the globe (Figure 1).

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