An antibody is a substance found in the blood that the body produces in response to a virus. If someone has an antibody blood test done to detect hepatitis C, the test is identifying if a person has antibodies to the virus, which would indicate that they were infected at some point. Another test is then needed to determine if the person is currently carrying the virus.
A genotype is the strain of the virus that a person was exposed to when first infected. About 75 percent of Americans with hepatitis C have genotype 1 (subtypes 1a and 1b). About 20 to 25 percent have genotypes 2 and 3 and a small number of people are infected with genotypes 4, 5 or 6. Genotype 4 is more common in Africa and genotype 6 is more common in Southeast Asia.
In 1957 scientists discovered the antiviral properties of interferon, which is a protein produced in the body in response to infection. Three different types were identified; alfa, beta and gamma, and they work by interfering with viral replication within host cells. In the 1990s, the first alfa interferon was approved by the FDA to treat hepatitis C.
Pegylation is a process that binds certain compounds to interferon molecules, That allows it to stay in the body longer and leads to better viral suppression. In the early 2000s, the first pegylated interferon was approved by the FDA to treat hepatitis C.
Ribavirin is used in combination with interferon and other drugs to treat hepatitis C. It is not effective at treating the virus on its own, but boosts treatment by inhibiting the ability of the hepatitis C virus to replicate.
The most current treatments involve interferon-free therapy, as interferon causes a host of undesirable side effects. In 2013, the FDA approved a drug called Sovaldi that can be used with Ribavirin but without interferon. It has a cure rate greater than 90 percent for genotype 2 and a good cure rate for genotype 3. In the future, interferon-free therapy should also be available for genotype 1.