Bringing viral hepatitis out of the shadows!

WHO aims to achieve hepatitis elimination by 2030. But to get there, there is an urgent need to bring hepatitis care closer to communities. And for that to happen, WHO recommends early diagnosis to identify people who may be at an increased risk of infection

Hepatitis, as we all know is an inflammation of the liver and can be caused due to alcohol abuse, medications, and certain medical conditions. However, hepatitis is often caused by a virus and is a matter of concern as it can lead to severe disease and liver cancer.

Elimination of viral hepatitis – a global concern

Did you know that viral hepatitis is three times more deadly than HIV and nine times more than malaria? It’s no wonder then that WHO is focusing its efforts to diagnosis, treat and prevent chronic viral hepatitis by bringing hepatitis care closer to the primary health facilities so that people get better access to early diagnosis and treatment.

WHO aims to achieve hepatitis elimination by 2030. To get there, WHO calls on countries to achieve specific interim targets by 2025:

To reduce new infections of hepatitis B and C by 50 %, and
To reduce deaths from liver cancer by 40 %
To ensure that 60% of people with hepatitis B and C virus are diagnosed
And 50% of those eligible receive appropriate treatment

In India, hepatitis C in particular is an emerging infection and an important pathogen causing liver disease. The high risk of chronicity of this blood-borne infection and its association with hepatocellular carcinoma underscores its public health importance.

Hepatitis C and blood transfusion

Blood transfusion is an easy mode for transmission of hepatitis C infection as it allows transmission of a large quantum of infective virions to the susceptible patient. In developed countries, the rapid improvement of healthcare conditions and the introduction of HCV screening for blood donors have led to a sharp decrease in the incidence of hepatitis C, but the epidemic continues to spread in developing countries, where the virus is still transmitted through unscreened blood transfusions.

Virological tools for diagnosis

Virological diagnosis of HCV infection is based on two categories of laboratory tests, namely

Indirect assays: Serologic assays detecting specific antibody to HCV (anti-HCV) (indirect tests)
Combined assays:Serologic assays detecting specific antibody to HCV (anti-HCV) and core antigen to hepatitis C
Direct assays:Assays that can detect, quantify, or characterize the components of HCV viral particles, such as HCV RNA and core antigen.

Generations in serological assays (ELISA):

The different generations of immunoassays for anti-HCV:

Generation	Significance
1^st Generation	Detection of antibodies to NS4 antigen only
2^nd Generation	Detection of antibodies to NS3, NS4 and core antigen
3^rd generation	Detection of antibodies to NS3, NS4, NS5 and core antigen

The window period has been documented to decrease from approximately 16 weeks to 10 weeks and finally to 8 weeks with the introduction of first-, second-, and third-generation anti-HCV ELISAs, respectively.

The 4^th generation assays

The latest, fourth generation of tests simultaneously detect HCV capsid antigen as well as antibodies to the core, NS3, NS4, and NS5 regions of the virus. These assays are also known as combination assays and offer a higher sensitivity and specificity.

In fact, owing to its reliability, the technical committee of NACO has reviewed specification for kits to be used in blood banks and encouraged the procurement of fourth generation assays.

Features	HCV 4^th Generation ELISA	HCV 3^rd generation ELISA
Detects HCV Antigen	✓	✕
Detects Anti-HCV IgG Antibody	✓	✓
Detects Anti-HCV IgM Antibody	✓	✕
Window period	< 28 days	> 66 days
Accuracy	Highly accurate due to antigen detection	Accurate

A window period is the time between the first infection and when the test can reliably detect the infection. Any third generation kit usually offers a window period in the reported range of 15 – 180 days. The simultaneous detection of antigen and antibodies with ErbaLisa HCV Gen4 Ag+Ab will greatly aid in screening HCV more accurately, as the window period for HCV detection will be reduced to less than 28 days.

Most of the analytical studies and research publications also suggest that the HCV core Ag assay is a potentially useful assay for screening blood donors. It greatly helps to minimize the risk of using HCV positive blood from a patient in the window period of HCV infection. The HCV core Ag assay may well be an alternative to the molecular techniques.

References:

Authored by:

Ajinkya Upasani

Asst. Product Manager – Immunology (Reagents)

Transasia Bio-Medicals Ltd.

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