Journal of Human Virology & Retrovirology HCV Vaccine: How Far are We? Submit Manuscript | http://medcraveonline.com Volume 3 Issue 2 - 2016 Varun Chauhan 1 , Kapil Goyal 2 and Mini P Singh 1 * 1 Department of Virology, Postgraduate Institute of Medical Education and Research, India 2 Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, India *Corresponding author: Mini P Singh (MD), Additional Professor, Department of Virology, Postgraduate Institute of Medical Education and Research, Chandigarh, India-160012, Tel: +91-172-2755199; Fax: 0091-0172-2744401; E-mail: Received: February 17, 2016 | Published: March 02, 2016 Mini Review J Hum Virol Retrovirol 2016, 3(2): 00084 Abstract Worldwide, hepatitis C (HCV) is considered as an important public health problem as it is associated with severe complications and high morbidity and mortality. Majority of infections are usually asymptomatic during initial phases, however majority of the infected individuals develop symptomatic disease during the latter phase of illness. Hepatitis C virus has seven genotypes and 67 subtypes and also different quasispecies are known to circulate in one particular individual. The diagnosis is usually established by serology/ molecular tests. HCV is a RNA virus, which is associated with high mutations rate. At present newer antivirals are available that are associated with good sustained virologic response, but these are very costly and are beyond the reach of common man in developing countries. Thus, vaccine candidates are required for preventing the infection. Though, different vaccine candidates are present, but all are in clinical trials and at present no commercially available vaccine is available. In the present mini- review, recent vaccine candidates have been discussed along with a summary of challenges being faced in the development of an ideal HCV vaccine. Keywords: HCV; Vaccine; Immune response; Animal models; Hepatitis C virus; VIPs Abbreviations: HCV: Hepatitis C Virus; HBV: Hepatitis B Virus; HCC: Hepatocellular Carcinoma; DAA: Directly Acting Antivirals; SVR: Sustained Virologic Response; NS5: Non-Structural Protein 5; ABIR: Antibody-Mediated Immune Response; CMIR: Cell- Mediated Immune Response; HIV: Human Immunodeficiency Virus; VLPs: Virus Like Particles; Th: T Helper Cells; HADV6: Human Adeno Virus Rare Serotype 6; Chad3: Chimpanzee Ad 3; CMV: Cytomegalovirus Commentary Worldwide, hepatitis C (HCV) is an important public health problem. Earlier, it was mainly associated with transfusion of HCV infected blood in the developing countries. However, due to intravenous drug abuse, now it is well recognized in developed countries also. As per World Health Organization (WHO) data, approximately 170-185 million people are globally suffering from chronic HCV infection [1,2]. More than 3,50,000 individuals are expected to die every year from hepatitis C related liver diseases [3]. HCV causes more severe clinical complications as compared to other viral causes of hepatitis. Hepatitis B virus (HBV) and Hepatitis C virus shares similarity in that both are transmitted parenterally. However, the two viruses are totally dissimilar in their genetic properties, course of infection, treatment options and availability of effective vaccine. Among majority of the patients, HCV during the initial period illness is usually asymptomatic and it is only during the later course of infection that patient develops clinical manifestations. About 15-45% of acute cases spontaneously clear the virus and around 55-85% in later period of their lives progress to chronic HCV infection, which further leads to liver fibrosis, cirrhosis and eventually hepatocellular carcinoma (HCC) in 15-30% of those having chronic hepatitis C [4]. In suspected patients diagnosis is confirmed by serology and/or molecular methods. However, majority of the patients are not diagnosed during acute phase that contributed to a pool of patients who transmit the infection via high-risk behavior, intravenous drug abuse, blood transfusion and organ donations. The most common indication of liver transplantation is the decompensating chronic HCV infection that alone accounts for 40-50% of liver transplants [5]. There are seven different genotypes (1-7) of HCV and 67 subtypes exist in nature [6]. The genotyping is important for deciding the treatment regimen as response to treatment and duration of treatment depends upon the specific genotype. Super infection with more than one genotype can also occur especially among high-risk groups, like injection drug users. However, genotyping methods are not widely available in developing countries and are also not affordable by all in developing countries due to limitation of resources [7,8]. Thus, research is required in the field of developing newer diagnostic tests for detecting different genotypes and nanotechnology and micro fluidics can be used to develop a point-of-care test [9,10]. Recent advances have been made in the treatment options due to the availability of new direct acting antiviral (DAA) drugs, which help in achieving sustained virologic response (SVR - a marker for cure) among 80-90% of patients after 12-24 weeks of therapy [11]. The newly approved two new DAA drugs are Sofosbuvir and Simeprevir [11]. Former drug acts by inhibiting HCV NS5B polymerase enzyme and latter one is a protease inhibitor that blocks specific protein needed by the hepatitis C virus to replicate. Moreover, efficacy of Simeprevir is markedly reduced in patients infected with HCV genotype 1a with an NS3 Q80K polymorphism. Thus, prior to initiation of therapy, screening for this mutation