What to Know About Hepatitis C Genotypes

Medically Reviewed by Gabriela Pichardo, MD on June 12, 2022
3 min read

"Hepatitis" means inflamed liver. The virus known as hepatitis C, or hep C, is the most common cause.

Scientists call the different types of hepatitis c “genotypes.” Each hepatitis C genotype has a different genetic makeup that helps define it.

There are six basic genotypes. Scientists break down each of these numbers into subtypes by letters, like 1a, 1b, etc. Some genotypes are more common in certain parts of the world and respond better to a particular treatment.

In the U.S., genotype 1 is the most common. It makes up about 75% of all U.S. cases. The other 25% are mostly genotypes 2 or 3. A few Americans may have genotypes 4, 5, or 6. Genotype 4 is most common in Africa, while genotype 6 is most common in Southeast Asia.

Your doctor can test your blood to find out whether you have hepatitis C and which genotype it is. Most people have one. But some have more than one. Your doctor might call this “mixed infection.”

You’re more likely to have a mixed infection if you:

  • Got blood products like platelets, plasma, red cells, or whole blood many years ago
  • Received blood products in a place that doesn’t check blood for hep C
  • Are on kidney dialysis
  • Inject drugs with shared or unsterilized needles

Keep in mind that you might carry the hep C virus even if you don’t have symptoms of hepatitis. Once you know your status and genotype, you and your doctor can decide on a treatment plan.

Medications known as direct acting antivirals, or DAAs, stop the hep C virus from making copies of itself. Some DAAs appear to work well on all hepatitis C genotypes. Others work on only one or some.

Your doctor will probably prescribe some combination of these medications:

Some pills combine two drugs into one pill.

You'll probably take these meds for anywhere from 8 to 12 weeks. But they may not be right for everyone because of things like cost or other illnesses.

Your specific genotype can tell your doctor important things about how to use those medications, what to watch for, and other drugs you might need.

For example, you may have a higher chance for cirrhosis (serious liver scarring) if you have genotype 1.

Genotype 3, the second most common subtype worldwide, may not respond as well to DAAs alone. In addition, this type might suggest that:

  • Liver disease may progress more quickly.
  • Liver cancer is more likely.
  • Insulin resistance might happen. When your body resists or doesn't respond to insulin as well as normal, you have a higher chance of heart disease and diabetes.
  • You might need longer, more challenging treatment (especially if you have cirrhosis or liver disease, or if you've had a previous treatment)

Your doctor might adjust or change your DAA treatment if you have: