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in Physiology or Medicine 2020 was awarded to Har
vey J. Alter, Michael Houghton and Charles M. Rice for the discovery of the hepatitis C virus (HCV), a virus that can cause cirrhosis and liver cancer. Before this discovery the majority of blood-borne hepatitis cases remained unexplained. Thanks to their findings, the causes were revealed and blood tests and new effective medicines have been subsequently developed – saving millions of lives. HCV can cause both acute and chronic hepatitis, ranging in severity from a mild illness lasting a few weeks to a serious, lifelong illness. It is the major cause of liver cancer. The most common modes of infection are through exposure to small quantities of blood. This can be the result of injection drug use, unsafe injection practices, unsafe healthcare, transfusion of unscreened blood or blood products, or sexual practices that lead to exposure to blood. According to the World Health Organization (WHO), an estimated 71 million people globally have chronic hepatitis C virus infection. In 2016, for example, approximately 399 000 people died from hepatitis C, mostly as a result of cirrhosis and hepatocellular carcinoma (primary liver cancer). In the 1940s it became known that two main types of hepatitis exist, one form being an acute disease caused by hepatitis A that is transmitted by contaminated water or food, and one form transmitted through blood and bodily fluids, which was more dangerous since it could lead to a chronic condition with development of cirrhosis and liver cancer. The discovery of the blood borne hepatitis B virus was made by Baruch Blumberg in the 1960s, leading to diagnostic tests and a vaccine, and was also awarded a Nobel Prize (1976). The hepatitis B virus, however, was found to not be the cause in all patients suffering from hepatitis. At the same time as Blumberg’s discovery, Harvey Alter was studying the occurrence of hepatitis in patients who had received blood transfusions. He found that a large number of cases remained after both hepatitis A and B had been excluded and he demonstrated that blood from these patients could transmit the disease to chimpanzees, the only other susceptible host besides humans. The unknown infectious agent had the characteristics of a virus and the illness became known as “non-A, non-B” hepatitis. Niklas Björkström, MD, PhD, Karolinska University Hospital and Karolinska Institutet iklas Björkström, Associate Professor, MD, PhD, Center for Infectious Medicine, Karolinska University Hospital and Karolinska Institutet, is a clinical microbiologist working as a physician and also performing research. A main task and responsibility in this work is to diagnose different viruses, bacteria, parasites and fungus, he says. “For example we screen all blood donations for chronic viruses. I did not experience the era before the hepatitis C virus was discovered but I can only image how it would have felt knowing that an unknown virus existed that most probably could spread in healthcare settings through blood donations,” Niklas says, emphasizing the importance of the three Laureates’ Nobel winning discovery. After Harvey’s findings, Michael Houghton and his colleagues used an untested strategy to isolate the genome of the new virus. They created a collection of DNA fragments from nucleic acids found in the blood of an infected chimpanzee, and predicted that some NORDICLIFESCIENCE.ORG 65 PHOTO MARKUS MARCETIC