Glossary

Words and phrases explained

Caesarean or C-section is a procedure to deliver a baby that involves making a cut through the abdominal wall to surgically remove the infant from the uterus.

CD4 cells are a type of white blood cell that help our bodies fight infection. These are also the cells that HIV infects and uses to make copies of itself.

Your CD4 count is the number of CD4 cells in one cubic millimetre (mm³) or millilitre (ml) of blood. Your CD4 count is one measurement of the stage of your HIV.
CD4 counts vary from person to person, but an HIV-negative adult would expect to have a CD4 count within the range of 400-1,400 cells/mL. Some factors, such as being tired, ill or pregnanct, can cause temporary drops in a person's CD4 count.
A CD4 count below 200 cells/mL is considered to be low and it is recommended to start treatment before it reaches this level. reaches that level. You are more vulnerable to infection if you have a CD4 count below 200 cells/mL.

Combination therapy is a term for using 3 or more drugs to treat HIV. Also called Highly Active Anti-Retroviral Therapy (HAART). Anti-HIV drugs are not effective for treating HIV individually (monotherapy), but they can be very effective in combination. For more info see the i-Base Introduction to combination therapy.

HIV transmission is when the virus passes from one person to another. When this is from mother to baby it is called mother-to-child transmission (MTCT), perinatal or vertical transmission. Children who become HIV-positive in this way are called vertically infected children

Monotherapy is using only one HIV drug and dual therapy is using two drugs. Neither strategy has been as effective as using 3 drugs for treating HIV. In some circumstances though, these strategies are still recommended for reducing mother-to-baby transmission.

Non-nucleoside reverse transmission inhibitors (NNRTIs or non-nukes) and protease inhibitors (PIs) are both types (or classes or families) of antiretrovirals that control the virus in different ways, both to each other and to NRTIs. So in addition to two nukes, triple therapy will generally contain either an NNRTI or a PI.

Nucleoside analogues (NRTIs or nukes) are one type of HIV drug and include AZT, ddI, 3TC, abacavir and tenofovir (a nucleotide). Usually a first HIV combination will include two of these drugs and either a non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI).

Opportunistic infections (OIs) are infections that can cause serious illnesses in people with low CD4 counts, as is the case with many HIV-positive people. OIs usually do not occur in people with healthy immune systems. Examples of OIs that occur in HIV-positive people (generally when they are not using combination therapy) are PCP, CMV and MAC.

Preclinical testing. before any drugs are tested on humans they will be tested in the laboratory and on animals. This will not always show what will happen when people use the drugs, but it can provide a guide to serious problems that could occur.

Prenatal refers to the period before a baby's birth, the time in which the foetus (developing baby) grows in the uterus.

Prophylaxis is when you take a drug to prevent an infection or reinfection before it occurs.

Resistance if you just take one drug (monotherapy) or a combination of drugs that are not strong enough to get your viral load undetectable then HIV will become resistant to the drugs.

If you are resistant to a drug it will no longer work as well and it may not work at all.
To avoid resistance you need to take a combination of at least 3 antiretroviral drugs.
It is important to avoid resistance in pregnancy.

Safety data means that a drug has been used safely in a certain number of people. Generally the more information we have on use of a drug in a large number of people, the more confidant we can be that it is safe to use in that population.

Transmission of HIV is when the virus passes from one person to another. When this is from mother to baby it is called mother-to-child transmission (MTCT) or perinatal or vertical transmission. Children who become HIV positive in this way are called 'vertically infected children'.

'Treat as non-pregnant adult' is a very common phrase in HIV and pregnancy. This means that generally your HIV is treated as if you were not pregnant. There are some exceptions, particularly when you do not need treatment for your own HIV and concerning some of the commonly used HIV drugs.

Viral load tests measure the amount of virus in your blood. The measurements are in copies per millilitre – for example 20,000 copies/mL. Viral load is one measurement of the progression of HIV.

The goal of treatment is to get your viral load to be undetectable ie below 50 copies/mL.
If a mother's viral load is undetectable when the baby is born, the chance of mother-to-child transmission is practically zero.