The currently available anti-HIV drugs cannot cure HIV. However, treatment with a combination of these drugs (usually three) can reduce the amount of HIV in your blood (your viral load) and prevent HIV from reproducing in your body. This allows your immune system to stay strong and fight off infections and other illnesses.

There’s very good evidence that the HIV treatment available today will work against the virus in the long term and keep your viral load undetectable indefinitely.

However, for this to be the case, it’s very important to take your HIV treatment properly. Adherence is the most important factor under your control in the success of your HIV treatment.

Not taking your HIV treatment properly can mean that the levels of the drugs in your blood are not high enough to properly fight HIV. If this happens, your HIV will be able to reproduce. The strains of HIV that reproduce when you’re taking HIV treatment can develop resistance to the drugs you are taking. Resistance can mean that your HIV treatment won’t work effectively.

Your treatment not working is likely to mean that your viral load will increase and your CD4 cell count, an important indicator of the health of your immune system, will fall. This situation increases your chances of becoming ill because of HIV.

If your viral load increases to detectable levels, you may need to change your HIV treatment. This new treatment might be more difficult to take than the combination you were taking before and could involve a risk of more, or new, side-effects.

Your HIV may also become resistant to drugs similar to those you are currently taking (that is, in the same ‘class’ of drugs). This is called cross-resistance and the risk varies between different classes of HIV drugs. You can find out more about the different drug classes in the NAM booklet Anti-HIV drugs.

When taken properly, HIV treatment can also lower viral load in genital fluids. This can greatly reduce the risk of HIV transmission during sex. Using condoms will further reduce the risk, as well as protecting you and your partner from other sexually transmitted infections and preventing unplanned pregnancy.

Bear in mind that having another sexually transmitted infection (STI), such as chlamydia or gonorrhoea, can also increase HIV viral load in genital fluids, possibly making you more infectious.

A consequence of not taking your HIV treatment properly can be that the amount of virus in your genital fluids increases, therefore increasing the risk of passing on HIV to your sexual partner(s). The HIV you pass on may also be resistant to one or more anti-HIV drugs. There’s more information about resistance later in this booklet.

In the UK, post-exposure prophylaxis (PEP) is available for the HIV-negative partner after some types of unprotected sex (sex without condoms). If either you or your partner has questions about the options available to you for reducing the risk of HIV being passed on, talk to your healthcare team.

You can find out more about each anti-HIV drug in the NAM booklet Anti-HIV drugs or by using NAM’s online tool, My drugs chart. Information about CD4 cell counts and viral load tests is available in the booklet CD4, viral load & other tests.