There are 11 different Genotypes to Hepatitis C and at least 50 different Sub-types. These numbers seem to grow as researchers find more and more Genotypes and sub-types around the world. The Genotype is now used, in conjunction with a liver biopsy, to help determine if treatment is necessary and is used in deciding how long the treatment regime should be.
Genotype 1 is the most difficult to treat, therefore if you have this genotype you should be on treatment for 48 weeks. Any other genotype should be treated for 24 weeks.
No matter which genotype you have, you should be given an HCV RNA PCR Quantitative test at the 24 week mark during your treatment. If you are any other genotype than 1, and you still have viral load at the 24 week mark, you should discontinue treatment, as you most likely won't get an UNDETECTED reading after this point. If you are a Genotype 1 (either a or b) you should continue with treatment for a full 48 weeks, as studies have shown that Genotype 1 is a slow responder, but does respond if treatment is extended for a longer period. Recent studies have suggested that a person's HCV subtype (or subtypes) may influence their possible response to interferon, or interferon-ribavirin combination treatment.
Current scientific belief is that factors such as duration of a person's HCV infection, their HCV viral load, age, grade of liver inflammation or stage of fibrosis may play an important role in determining response to interferon treatment. This said, it may also be true that none of this is a factor in whether a person will go on to cirrhosis or not. Many people have proved this theory wrong. HCV is a very individual disease and progresses with the individual which makes it difficult for the researchers.
It
is believed that the hepatitis C virus has evolved over a period time since
coming to the attention of medical personnel in 1942. This would explain
the current general global patterns of genotypes and subtypes:
| 1a | Found most often in the US, United Kingdom, and Europe. |
| 1b | Found mostly in Japan and Europe. Common in US. |
| 2a,2b,2c,2d | Found mostly in Japan and China. Common in US. |
| 3a,3b,3c,3d,3e,3f | Found mostly in Scotland & other parts of the United Kingdom. Common in US. |
| 4a,4b,4c,4d,4e,4f,
4g,4h,4i,4j |
Found mostly in the Middle East and Africa |
| 5a | Found mostly in Canada and South Africa |
| 6a | Found Mostly in Hong Kong and Macau |
| 7a,7b | Common in Thailand |
| 8a,8b | Common in Vietnam |
| 9a | Common in Vietnam |
| 10a | Common in Indonesia |
| 11a | Common in Indonesia |
Having
one of these genotypes does not necessarily mean you have been to one of
these countries. Donated blood for transfusions comes from all over the
world. If you got HCV through shared needles, there is no telling what
genotype you may wind up with.