Six major strains (genotypes) of the
hepatitis C virus (HCV) cause infection. You may be
infected with more than one genotype at a time.
Genotype 1 is the most common strain in the
Genotypes 1, 2, and 3 are found
Genotype 4 is found throughout northern
Genotype 5 commonly is found in South
Genotype 6 is common in Asia.
Genotype testing is done with a blood test.
How genotype affects treatment
Although genotype tests are not used to diagnose HCV infection,
they may be done before treatment begins. Knowing the genotype may help a
doctor choose the best treatment plan. You should know your genotype before
Antiviral medicines are more likely to work for people who have
genotype 2 or 3.
If blood tests show that you have responded to antiviral therapy
(the virus is not detected in your blood) after 6 months, treatment may
Continued for another 6 months, if you are
infected with genotype 1.
Stopped, if you are infected with
genotype 2 or 3. Prolonging treatment does not seem to provide any more
The genotype of HCV does not appear to have any effect on the
severity of HCV infection or to affect your risk of developing cancer of the
liver (hepatocellular carcinoma).
How this information was developed to help you make better health decisions.