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Explained: The discovery of Hepatitis C virus that helped three scientists win the Medicine Nobel

7th October, 2020 Health

Context: Three scientists share this year’s Medicine Nobel for the discovery and identification of the Hepatitis C virus.

  • This year’s Nobel Prize in Physiology or Medicine rewards an effort that eventually made blood transfusion safer for everyone.
  • Discovery of a new virus that was the cause of a vast majority of chronic hepatitis cases, or cases of serious liver inflammation, in patients who required blood transfusion. This virus was eventually called Hepatitis C virus.
  • Since the discovery and identification of the virus in the 1970s and 1980s, a cure has been found for the disease, and effective anti-viral drugs are now available.
  • Tests have been developed to identify blood that has this virus, so that infected blood is not given to any patient.
  • According to the World Health Organization, about 71 million people (6 -11 million of them in India) have chronic infection with the Hepatitis C virus, which also happens to be major cause of liver cancer.
  • In 2016, this viral infection led to the death of nearly 400,000 people across the world. A vaccine for the disease has still not been developed.

What was known about hepatitis before the discovery of the Hepatitis C virus?

  • Before the discovery of the Hepatitis C virus, two other viruses were known to cause hepatitis in patients.
  • The Hepatitis A virus was known to spread mainly through contaminated food and water, and caused a relatively milder form of liver inflammation.
  • Hepatitis B, discovered in the 1960s, was known to transmit mainly through infected blood, and caused a more serious form of the disease.
  • The discovery and identification of Hepatitis B virus facilitated the development of a diagnostic test to detect its presence in blood.
  • Thereafter, only blood sanitised from this virus would be given to patients, but it was observed that even this sanitised blood was able to prevent only 20% of the blood-borne hepatitis cases. It was then that the search for the new virus began.

Why is it significant?

  • The discovery of the Hepatitis C virus (HCV) was one of the important milestones in improvement in public health that had raised hopes for eliminating the disease.
  • “The discoveries of HBV and HCV, and the establishment of effective screening routines, have virtually eliminated the risk of transmission via blood products in many parts of the world.
  • Thanks to the development of highly effective drugs against HCV, it is now possible, for the first time in human history, to foresee a future where the threat of this virus infection is substantially reduced and hopefully soon eliminated.
  • “Three main causes of blood-borne infections — Hepatitis B, Hepatitis C and HIV — all have been identified, and they no longer infect the blood that is required by patients.

How is Hepatitis C treated?

  • “A vaccine for this has not been developed mainly because it’s a very fast-changing virus.
  • But it is possibly the only chronic virus for which a definitive cure is now available,”
  • “Anti-viral drugs could be developed based on the understanding of the biology of the virus to which Harvey’s lab contributed very significantly.

Indian effort

  • One of the important steps towards finding a vaccine was taken by an Indian company in the late 1990s.
  • Hyderabad-based Shantha Biotech, which produced the first recombinant DNA-based vaccine for Hepatitis B infection, had begun work on Hepatitis C as well.
  • It had funded the work of a US-based Indian-origin scientist who had succeeded in sequencing the entire genome of the Hepatitis C virus present in the Indian population. But no progress was made after that.