Key points
- A low CD4 count means that HIV has weakened your immune system and may be making you ill.
- HIV treatment will strengthen your immune system and extend your life.
- While your CD4 count is low, you may also need to take antibiotics to prevent infections.
HIV treatment is recommended for everyone who has HIV, but it is especially important for people with a low CD4 count. This indicates that HIV has weakened their immune system to such an extent that they are at risk of serious illnesses.
Every year several thousand people learn that they are HIV positive when their CD4 count is already below 350 (two in five of all people diagnosed in the UK in 2018).
If you are diagnosed with HIV with a low CD4 count, you will be recommended to start HIV treatment very soon or even straight away. You may need additional treatment and monitoring, but there is a good chance that you will respond well and your immune system will start recovering.
The immune system and HIV
The immune system's different cells work together to protect the body against pathogens such as viruses and bacteria.
The human immunodeficiency virus (HIV) mainly infects the CD4 cells in the immune system. Over years of untreated HIV infection, CD4 cell numbers usually drop gradually, but constantly, and the immune system is weakened. If nothing is done to slow or halt this destruction, it becomes unable to fight infections and you become ill.
Antiretroviral drugs interrupt this process. The aim of treatment is to reduce levels of HIV in your body (often called your ‘viral load’), so your CD4 count increases and your body’s ability to fight infections improves.
Starting HIV treatment after diagnosis
The sooner you start to take HIV treatment, the sooner you can benefit from it. HIV treatment will strengthen your immune system, reduce the amount of HIV in your body and prevent illnesses from occurring. Effective HIV treatment also helps prevent you from passing HIV on to someone else.
If your CD4 count is below 200 your doctor will recommend starting HIV treatment immediately. With a CD4 count below 200 your body is vulnerable to opportunistic infections. These are infections the immune system can usually prevent on its own but with a low CD4 count the immune system is not able to fight them off. Opportunistic infections can be very serious and cause potentially life-threatening illnesses.
To prevent the development of these infections you may also need to take antibiotics (a treatment called prophylaxis). Once your CD4 count has increased to above 200, the prophylaxis treatment will be stopped. If you are already ill with an infection, you may start treatment for this before you start HIV treatment.
How effective is HIV treatment in people with low CD4 counts?
HIV treatment is highly effective. Many people's CD4 count will start to climb after starting treatment. Long-term HIV therapy can result in your CD4 count returning to the expected level for your age. Once your CD4 count improves, with continued treatment and care, your life expectancy is very good.
Other factors, such as age, viral load, genetic make-up, lifestyle and quality of health care will also affect your future health and life expectancy.
After starting HIV treatment, some people’s CD4 cell counts do not increase, or rise very slowly, even though their viral load is ‘undetectable’. This can mean they are at greater risk of becoming ill and of dying of HIV-related illnesses. They may also be at greater risk of developing heart disease and cancers.
If this is the case, it is very important that you receive careful health monitoring so that any developing health problems can be detected and treated early.Your lowest-ever (also called ‘nadir’) CD4 count may have an impact on your long-term health, even if your immune system has since recovered. Current data suggests that having once had a very low CD4 count is associated with a slightly higher chance of developing some health problems in the future.