In 2015, the World Health Organization (WHO) estimated 71 million people affected by hepatitis C virus (HCV) worldwide that represents about 1% of the world inhabitants (
1). This pathology is the cause of more than 400000 death per year because of complications related to the progression of the disease, such as cirrhosis and its complications or hepatocellular carcinoma (HCC) (
1). The distribution of HCV prevalence, which is different among several considered geographical areas, is currently known. However, many of these data represent only a theoretical evaluation rather than the real-life situation because of a large number of patients living in the world areas where it is difficult to get epidemiological information. Italy, Romania, Spain, Germany, France, United Kingdom, Poland, Greece, and Bulgaria are the countries in which there are more than 80% of the patients affected by HCV in Europe (
2). Currently, a small number of data sets are available on the epidemiology of HCV infection in Italy (
3-
6). However, the known data demonstrate a prevalence of seropositivity for HCV that is higher in the Southern areas (7.3%), Central island (6.1%), and Northern ones (about 1.6%) (
4). In this setting, Campania represents a region with a high prevalence of HCV infection, as demonstrated by data concerning the number of direct-acting antiviral (DAA) prescriptions since the beginning of their use (http://www.aifa.gov.it/content/aggiornamento-epatite-c). The population size of the Campania region is about six million inhabitants and the main risk factors for HCV transmission are a history of surgical interventions or dental surgery and at least one previous blood transfusion or injective drug use. Few patients had an anamnesis of accidental puncture or tattoo/piercing. Finally, another little percentage of patients were born from an HCV-positive mother (
7).
The history of HCV therapy in recent past years has been characterized by a succession of pharmacological innovations, which led us to obtain high healing rates. The association of Interferon (IFN) and Ribavirin (RBV) has been essential for the treatment of people affected by this pathology for a long time (
8,
9). However, the therapeutic achievement was limited: in fact, it worked in about 50% of the patients affected by HCV genotype 1.80% of those affected by HCV genotype 2, and 65% of those affected by genotype 3. Moreover, a higher rate of side effects related to the use of IFN was present. For these reasons, there was a difficulty in treating ill people with these drugs. In fact, the identification of predictive factors of therapy response has been often necessary. For example, some daily dietary components, evaluated by a nutritional assessment, such as unsaturated fatty acids, iron, zinc, vitamin A, and niacin and alcohol intake, were significantly different between responder and non-responder patients to IFN therapy. Genotype, age, body mass index, steatosis, and fibrosis were independent predictors of therapy outcomes (
10).
Furthermore, the rapid virological response (RVR) was demonstrated to be the strongest predicting factor of sustained virological response (SVR) and infection with HCV genotype 2 was significantly associated with high RVR rate (
11). In 2011, DAAs non-structural protein (NS) 3/4A proteases inhibitors, Telaprevir and Boceprevir, were approved to treat HCV genotype 1 infection along with pegylated IFN and RBV (
12) reaching eradication rates of about 70% in chronic hepatitis C infected patients. However, this therapy has caused a dramatically significant increase in side effects in addition to those that were already associated with IFN and RBV use, particularly anemia and skin adverse events (
13). The second and third generation DAA introduced in 2013 - 2014 improved the efficacy and the tolerance of anti-HCV treatment (
14,
15), with SVR rates of 90 - 95%. The evolution of antiviral regimens has led to the development of pangenotypic drugs and a shorter treatment with a small number of tablets (up to daily mono-administration). Therefore, an elevated efficacy is the reason why it is possible to accept the pharmacoeconomic model elaborated to cure the infection (
16). Even if new DAA regimens are characterized by SVR percentages, obtained by recording trials and real-life ones, which include 90 - 95% of the treated patients, the question concerning 5 - 10% of patients who fail the first line treatment is yet open. HCV is able to modify its genetic structure in order to acquire resistance against new generation drugs, especially during antiviral therapy (
17-
19). The most frequent mutations occur in the genic region, which codifies for NS5A, infrequently for the NS3 and NS4A regions and NS5B ones. Therefore, it is necessary to start a second line treatment according to information obtained through specific resistance tests. In fact, NS3 mutations can persist for a limited time after the therapeutic failure; on the other hand, other mutations can also persist for several years after its resolution (
17).