HIV is a virus which attacks the immune system – the body’s defence system against infection and illness. If you have HIV, you can take drugs to reduce the level of HIV in your body. By taking these drugs, you can slow down or prevent damage to your immune system. These drugs are not a cure, but they can help you stay well and lead a longer and healthier life.  Anti-HIV drugs are known as antiretroviral drugs.

HIV mainly infects cells in the immune system called CD4 cells. Over many years of HIV infection, the number of CD4 cells drops gradually but continually and the immune system is weakened. It becomes unable to fight infections and a condition called AIDS (acquired immune deficiency syndrome) follows. Antiretroviral drugs work by interrupting this process. 

An untreated person with HIV may have thousands or even millions of HIV particles in every millilitre of blood (‘copies’). The aim of treatment is to reduce the amount of HIV (known as the ‘viral load’) to very low levels; this is called an ‘undetectable’ viral load. This is generally below 50 copies per millilitre of blood, but there are some ultra-sensitive tests that can measure below 20 copies/ml. 

You can find out more about viral load testing in the NAM booklet CD4, viral load & other tests.

To give you the best chance of reducing the amount of HIV in your blood to an undetectable level, your doctor will usually recommend that you take a powerful combination of at least three antiretroviral drugs (sometimes known as highly active antiretroviral therapy, or HAART). Once your viral load has become undetectable, your immune system should begin to recover, and your ability to fight infections and your general health are likely to improve.