VAX Glossary
African AIDS Vaccine Programme.
A substance that increases an immune response but is not specific. Adjuvants are used in many vaccines.
African Coalition of AIDS Service Organizations.
Immune defense proteins which block virus, bacteria and microorganisms that are “free” in the blood, and have not infected any of the body’s cells.
A group of genetically-related forms of HIV. Clades are also called genetic subtypes and generally have geographic distribution patterns. For example, clades A and D are most common in east Africa; clade B HIV is found in North America and Europe.
A group of people who are followed over the course of a scientific study.
An immune response (immune cells or antibodies) that corresponds to a high degree of vaccine protection. We do not yet know which type or level of immune response indicates protection against new HIV infection. A correlate will be identified by testing vaccines in human trials and studying the immune responses from people who are protected from HIV infection.
A DNA vaccine against HIV consists of a molecule that closely resembles a fragment of the HIV genome (the genetic material that contains all of the information HIV needs to make copies of itself.) The fragment cannot cause HIV infection, but when it is introduced into the body it may still cause immune responses that can fight HIV.
gp120 is a molecule found on the outer surface (envelope) of HIV. gp120 binds to the CD4 molecule on helper T cells during infection. It has been studied as an experimental AIDS vaccine because the outer envelope is the first part of the virus "seen" by immune defenses called neutralizing antibodies.
International Council of AIDS Service Organizations.
Experimental treatments or vaccines given to people infected with HIV to improve their ability to fight the virus; at present, no effective immune based therapies have been identified.
A complex system of cells and substances that work together to protect the body from infections and illnesses.
The strength of the immune responses produced by a vaccine; these immune responses are measured through laboratory tests on a sample of the volunteer’s blood.
The rate of new infections per year, measured by determining the number of new infections in a specific population over a given period of time. HIV incidence rates are often expressed as percentages (the percentage of people in the population who acquired HIV in one year).
Physical structures and supplies that form the foundation for delivering services. Vaccine-related infrastructure includes refrigeration systems and storage facilities to keep the vaccines at correct temperatures, transport systems to deliver the vaccines, inventory systems to keep track of vaccine supplies, as well as clean water, electrical power, and communications facilities.
Kenya AIDS NGO Consortium.
A change in genetic material. This may occur at a single point (an individual nucleotide) or it may involve a partial loss or gain of stretches of genetic material.
Immune defenses that coat the surface of foreign invaders (such as HIV) in the blood. Neutralizing antibodies prevent the invader from multiplying itself or infecting cells.
A large study that is designed to determine the ability of a vaccine to protect against HIV infection or disease. Phase III trials usually include hundreds or thousands of volunteers and can also gather additional information about safety needed to evaluate the overall benefits and risks of the vaccine.
An inactive substance given to some study participants, while others receive the test substance (e.g., a vaccine or a drug). Placebos provide a more accurate basis for evaluating the activity of the test substance.
Post-exposure prophylaxis (PEP):
Prophylaxis means disease prevention. The goal of PEP for HIV is to prevent HIV infection by taking antiretroviral medications (for roughly 28 days) starting as soon as possible (usually within hours) after high risk contact. PEP is not 100% effective.
The number of cases of infection in a population at a given time. This figure is generally given as a percentage or as the number of cases per 100,000 people.
Recombination is the process by which pieces of genetic material from two different sources are joined (spliced) together. A recombinant is the new genetic material that is formed or the protein(s) that it produces.
A process by which pieces of genetic material from two different sources are joined (spliced) together.
The process of “reading” genetic material, which is composed of building blocks called nucleotides. Sequencing reveals the order of nucleotides in a given chain and shows the genetic “fingerprint” of the virus.
Syringe exchange is a “harm reduction” strategy designed to reduce the risks associated with intravenous drug use. Syringe exchange sites allow IDUs to swap used needles for clean ones and reduces the risk that IDUs will share or re-use needles that are contaminated with HIV and other diseases such as hepatitis.
A type of immune cell (white blood cell) called a T lymphocyte. Immunogens activate T cells in what is called a cell-mediated immune response.
A measure of the amount of virus in a blood sample. HIV viral loads refer to the number of copies of virus found in one milliliter of blood plasma.