Acquired Immunodeficiency Syndrome (AIDS)
The term AIDS describes the most serious stage of HIV infection when the immune system is severely impacted and too weak to defend itself against life-threatening infections and cancers.
Antiretroviral Therapy (ART)
Antiretroviral therapy, commonly referred to by its acronym ART, is an HIV treatment regimen. Highly active antiretroviral therapy stops the virus from making copies of itself in the body, therefore controlling the infection. It helps the immune system restore itself, halts disease progression, and prevents opportunistic infections from developing. ART is able to reduce HIV to such small quantities that it can no longer be detected by standard blood tests, nor can it be transmitted to others.
CD4 Cells
CD4 cells are an important part of the immune system. A CD4 count indicates how strong the immune system is, more specifically, how strong the immune system is to fight off infections. HIV affects the immune system by destroying CD4 cells and if a CD4 count drops too low, the risk of serious opportunistic infections increases. However, CD4 count recovery is possible with ART, meaning CD4 levels can go back to higher levels to keep people healthy.
Co-Infection
Co-infection is the simultaneous invasion of the body by two pathogens. In this study, the term co-infection is referring to the presence of the human immunodeficiency and hepatitis C viruses in the body at the same time.
Cohort
A cohort is any designated group of people who are followed or traced over a period of time. For example, all of the students in a class, everyone born in Canada in 1984, or a group of individuals participating in a study.
Cohort Study
A cohort study is an observational study in which a group of subjects are followed over time. Information is collected about the subjects’ characteristics and exposures and then they are followed to see which subjects experience the health outcome of interest. For example, the outcome of interest could be a heart attack, cancer or liver disease. The number of people who experienced the outcome is compared between those who were exposed to a factor and those who were not exposed. For example, the exposure of interest may be alcohol, medication or high cholesterol. It is very important that the investigator is not involved in choosing whether or not a subject is exposed, and instead only observes what happens.
Direct Acting Antivirals (DAAs)
Direct acting antivirals (DAAs) are medications used to treat hepatitis C. They block the ability of the hepatitis C virus to replicate. Treatment consists of taking one to three pills per day for eight or 12 weeks.
End-Stage Live Disease (ESLD)
End-stage liver disease occurs when the liver has minimal function. The only treatment for ESLD is liver transplantation.
Highly Active Antiretroviral Therapy (HAART)
Highly active antiretroviral therapy was introduced in the mid-1990’s and consists of a combination of at least 3 antiretroviral medications; 2 nucleoside reverse transcriptase inhibitors (NRTIs) plus either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI).
Hepatitis C (HCV)
Hepatitis C is an RNA virus that is transmitted through blood and attacks the liver. Those who are infected often do not show symptoms for a long time. It is possible for the body to clear the virus however, those who have a weakened immune system are less likely to do so. Chronic infection with HCV may lead to scarring of the liver, liver cancer or liver failure.
Hepatic Fibrosis
Hepatic fibrosis refers to the accumulation of scar tissue in the liver. The scar tissue is the result of repair after injury due to infection, alcohol consumption, toxins or other factors.
Human Immunodeficiency Virus (HIV)
Human immunodeficiency virus is a retrovirus that is transmitted through blood, semen, vaginal fluids and breast milk. HIV attacks the immune system and causes Acquired Immune Deficiency Syndrome (AIDS).
Opportunistic Infection
Opportunistic infection or disease occurs when pathogens that are normally fought off by a person’s immune system cause illness because a person’s defenses are weakened by factors such as a poor diet or HIV infection.