" HCV DIAGNOSTICS,DRUGS AND VACCINES HCV DIAGNOSTICS, DRUGS AND VACCINESHepatitis C is a serious liver disease that results from infection with Hepatitis C Virus (HCV).It was identified as a causative agent for non-A and non-B viral hepatitis in late 1970s. HCVaffects more than 200 million people worldwide. Patients are generally asymptomatic and getdiagnosed late. Besides research, the key for effective control and elimination of the virus isearly diagnosis which requires increase in awareness and broad diagnostic screeningprogramme. Due to its initial non-specific flu like symptoms the disease is not clinicallyrecognisable and requires broad healthcare screening programmes. Despite high levels ofHCV replication, the HCV-specific immune responses remain undetectable in most infectedindividuals for several weeks suggesting that the virus escapes from the immune system andimpair immune responses. HCV diagnosis plays a key role in determining and deciding thetreatment procedure and the duration of treatment. HCV diagnostic test include the serologicand the molecular diagnostic testing (Figure 1). The serologic testing detects humanantibodies generated against the HCV infection where as the molecular test detects the viralRNA.? Serologic Testing1. Enzyme Immunoassay - The third generation EIA is designed to detectantibodies that bind the core and the nonstructural regions of HCV.2. Point of Care Rapid Immunoassays- The OraQuick HCV Rapid antibody test(OraSure Technologies, Bethlehem, PA) was approved by FDA in 2010 as apoint-of-care test. The specimen type includes whole blood, serum or plasma.The nitrocellulose membrane is immobilised with synthetic peptides of core,NS3 and NS4 antigens. A reddish purple line is generated within 30 min in the presence of anti-HCV antibodies in the specimen on addition of colloidal gold1 labelled protein A. These rapid tests are cheap and fast? Molecular HCV RNA test- Molecular test detects the HCV RNA and is commonly called as Nucleic Acid Testing(NAT). The HCV RNA is detected 1-2 weeks after initial infection resulting in a positiveHCV NAT test. The quantitative HCV NAT test is ultrasensitive and can detect as few as5copies/mL. The detection and quantitative is important as it helps in -1. In diagnosing chronic HCV infection2. A guide to treatment decisions3. Used in monitoring response to therapyIt is also used to identify the stage of infection, if a NAT result is negative for a serologicpositive case then it indicates that the patient has a resolved infection or spontaneous2 resolution. However, in cases of chronic infection a second NAT test should be performed .Figure 1- Interpretation of HCV results Source: Centers for Disease Control and Prevention (CDC). Testing for HCV infection: anupdate of guidance for clinicians and laboratories. MMWR Morb Mortal Wkly Rep. 2013;62:362-5.? HCV Genotyping HCV is highly genetically diversified virus with seven distinct genotypes and numeroussubtypes of the virus. Genotype determination is important as it plays a direct role in3 determining the treatment and making correct therapeutic decisions . Methods to determinethe genotype include-1. The VERSANT HCV genotype assay is a probe based assay also called LiPA(Line Probe Assay), in this the 5’UTR is amplified using biotinylated primersfollowed by its hybridisation to genotype-specific probes impregnated on a4 membrane and the result is detected with streptavidin based on colorimetry .Thismethod determines the genotypes but can’t distinguish between the subtypes.2. Restriction Fragment Length Polymorphism (RFLP) of the highly conserved 5’UTR region. This technique is easy, affordable but has disadvantages like low5, 6 sensitivity for typing low RNA levels and cannot determine all the genotypes . 3. Nucleotide sequencing is the gold standard confirmatory test where nucleotidesequencing of the UTR or E1 gene or NS5B gene is compared with the knowngenotype databases by computational analysis (BLAST), these results willdetermine the genotype of the HCV patient. This method is expensive and time- 7 consuming but is necessary for therapeutic decisions 4. Abbott Real time PCR HCV assay uses the TaqMan technology to determine the8 genotype of the patients . However this is expensive, require expertise andcannot differentiate the subtypes.HEPATITIS C VIRUS VACCINE PROGESSHepatitis C Virus infection is still a major global burden. Since its discovery in the year 1989,till date there is no licensed vaccine for HCV. Development of vaccine for HCV has beenchallenging due to high genetic diversity of the virus, restricted humoral and cell mediatedresponses, limited potential of the adjuvant. Despite this, research on developing a successfulvaccine is ongoing. The different regimens for drug discovery include use of direct actingantiviral (DAA), targets inducing T cell response, developing neutralizing antibodies anddrugs targeting host proteins. The different strategies employed for vaccine developmentinclude the recombinant vaccines, DNA vaccines, Vector based vaccines and syntheticpeptide vaccines. A major outbreak in HCV treatment occurred with the discovery of the 2direct acting antivirals Teleprevir and Boceprevir, these protease inhibitors were FDAapproved in 2011 but due to their low genetic barrier and side effects, they are used merely incombinations. The discovery of these paved way for the discovery of several direct actingantiviral. In 2014 several DAA have been discovered and some of which have been FDAapproved and are currently used for treatment of HCV.? Direct Acting AntiviralsThe direct acting antivirals came into action when FDA approved the two NS3/4A proteaseinhibitors named telaprevir and boceprevir for treatment in combination with PEG-INF/RBV.The currently developed DAA are against HCV protease NS3, NS5A and NS5B ending with“-previr”, “– avir” and “–buvir” respectively and different combinations have been9 recommended by EASL (Listed in Table 1). "