Genotypes

The hepatitis C virus (HCV) is an RNA virus related to the flavivirus family, which includes yellow fever, dengue fever, West Nile fever and Japanese encephalitis. RNA viruses are genetically less stable than DNA viruses, and are prone to mutate during replication. It’s a common misconception that hepatitis C is just one virus, but in reality (as a result of mutation over hundreds of years), it’s a group of very closely related strains. They are similar enough to be called HCV, but based on genetic differences, they can be classified into distinct groups called genotypes.

Treatment protocol for hepatitis C varies depending on the genotype of the hepatitis C virus that is being treated.

The most commonly used classification scheme for HCV was established by Dr P. Simmonds. This system classifies hepatitis C into major genotypes, numbered 1, 2, 3, 4, etc.

Within the major genotype groups there are more closely related strains called subtypes. These have a designated lower case letters, such as 1a, 1b, 1c, etc. There are at least six major genotypes (1-6) with many subtypes. Proposed types 7, 8, 9, 10 and 11 may be different to genotypes 1-6, or they may be subtypes of 1-6.