What are genotypes?

There are several different strains of Hepatitis C, called genotypes.

In order to survive, the Hepatitis C virus mutates or evolves so that our immune systems are less able to recognise and destroy it. In this way, different strains or genotypes are formed.

Currently, throughout the world, there are 11 recognised Hepatitis C genotypes. These are numbered simply 1-11. The most common genotypes found in Scotland are genotypes 1, 2 and 3.

Although very rare, it is possible to be infected with more than one genotype.

Depending on which genotype you have, your treatment duration and the drugs you have to take may vary. Your genotype subtype may also have an effect on how likely treatment is to work and the duration of your treatment.

Subtypes

Genotypes also have subtypes (different strains of the same genotype) including:

Genotype 1a, 1b, 1c
Genotype 2a, 2b, 2c
Genotype 3a, 3b
Genotype 4a, 4b, 4c, 4d and 4e
Genotype 5a
Genotype 6a
Genotype 7a, 7b
Genotype 8a, 8b
Genotype 9a
Genotype 10a
Genotype 11a

Genotype subtypes around the world

Certain genotypes are more prevalent in certain parts of the world, but the most common genotype is 1. Genotypes mainly found in different parts of the world are as follows:

Genotype 1a - mostly found in North and South America, also common in Australia
Genotype 1b - mostly found in Europe and Asia
Genotype 2a - most common genotype 2 in Japan and China
Genotype 2b - most common genotype 2 in the US and Northern Europe
Genotype 2c -most common genotype 2 in Western and Southern Europe
Genotype 3a - highly prevalent in Australia and South Asia
Genotype 4a - highly prevalent in Eygpt
Genotype 5a - highly prevalent only in South Africa 
Genotype 6a - restricted to Hong Kong, Macau and Vietnam
Genotypes 7a and 7b - common in Thailand
Genotypes 8a, 8b and 9a - prevalent in Vietnam
Genotypes 10a and 11a - found in Indonesia