Hepatitis C Genotypes
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 United States.
- Genotypes 1, 2, and 3 are found worldwide.
- Genotype 4 is found throughout northern Africa.
- Genotype 5 commonly is found in South Africa.
- 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 treatment starts.
The antiviral medicines peginterferon and ribavirin are more likely to work for people who have genotype 2 or 3. These medicines also are used to treat people who have genotypes 5 and 6.
For people who have genotype 1, another medicine, such as boceprevir or telaprevir, is used along with peginterferon and ribavirin to treat hepatitis C.
If blood tests show that you have responded to antiviral therapy (the virus is not detected in your blood) after 6 months, treatment may be:
- 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 benefit.
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.
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer W. Thomas London, MD - Hepatology
Current as ofJune 4, 2014
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