Generally, those who develop hepatitis C virus (HCV) are only infected with one of the six distinct genotypes of the virus. Of those six genotypes, genotype 1 is the most common. What’s more, it’s also the hardest to treat.

Hep C primarily spreads through contact with blood from an infected person. But treatment of the illness depends on which genotype is wreaking havoc.
Simply defined, genotype is a classification given to a virus based on genetic material found inside its strands. But each genotype also contains multiple subtypes.

One recent study published in the journal Hepatology checked the prevalence of hep C genotypes worldwide. Findings showed that genotype 1 accounted for 46 percent of all HCV infections.

This information, according to Jane Messina, MD, one of the study’s co-authors, is key to “developing new treatment strategies that may save millions of lives around the world.”

Of the remaining five genotypes, Messina and her colleagues found that HCV genotype 3 was the second highest among people worldwide. Next in order of prevalence were genotypes 2, 4 and 6.