More than 83 million people worldwide are infected with hepatitis C (HCV) genotype 1, and accounts for 46 percent of al HCV cases. A recent study analyzed 1,217 studies that reported on all HCV genotypes between 1989 and 2014. The study included 117 countries and represents 90 percent of the world population.
Genotype 1 is the most difficult to treat
Treating hepatitis C depends on the genotype, and genotype 1 has proven to be the most difficult to treat. But new medications, such as simeprevir and sofosbuvir, have been able to show high cure rates for genotype 1.
Genotype 3 is the second most prevalent
Genotype 3 was found to affect about 54.3 million people, and account for 30 percent of all HCV cases worldwide. Genotypes 2, 4 and 6 combined account for 23 percent of all HCV cases, and genotype 5 accounts for 1 percent of cases.
Genotypes 4 and 5 more prevalent in lower income countries
Though genotypes 1 and 3 are most dominant worldwide, lower income countries have a higher rate of genotypes 4 and 5. Researchers say that other genotypes can increase if they find efficient transmission routes, such as in Egypt where genotype 4a is widespread due to unsafe injections.
Most genotypes have epidemic potential
Researchers suggest that under the right circumstances most or all of the genotypes could have the potential to become epidemic. They say that social, behavioral and demographic factors are more important than genetic variation of the virus in determining the global presence of the genotypes.