This factsheet is for people who have HIV/AIDS, or who would like information about it.

Human immunodeficiency virus (HIV) is a virus that attacks the immune system and increases the risk of infection, serious illnesses and some cancers. Acquired immune deficiency syndrome (AIDS) is the point at which the immune system has been weakened so much by HIV that it can't fight life-threatening infections and illnesses.


Around 91,500 people were living with HIV in the UK at the end of 2010 – over a quarter of these people didn’t know they were infected.

The majority of HIV infections are in heterosexuals; usually people who have come to live in the UK from countries where HIV is widespread. Infections are also common among men who have sex with men.

Although there isn’t a cure for HIV, it can be effectively controlled with treatment and most people can live healthy and productive lives.

The immune system

When your immune system is healthy, it protects your body against infections caused by bacteria and viruses. White blood cells find and destroy germs that your body sees as 'foreign' and this stops you developing serious diseases.

HIV avoids being detected and destroyed by your immune system by changing its outer 'coat' again and again. It multiplies (replicates) inside a type of white blood cell called a CD4 cell. This kind of cell is normally involved in helping other types of immune cell to attack and destroy bacteria and viruses.

As HIV multiplies, it destroys the CD4 cells in your body, so there are fewer of them. Having fewer CD4 cells means that your body's ability to fight other infections is weakened and your defences against certain cancers is reduced.

Symptoms of HIV/AIDS

Primary HIV infection

The first few months after you’re infected with HIV is called primary HIV infection, or acute HIV infection. You might also hear this called seroconversion. You might not have any symptoms of HIV infection, but if you do, they will usually start a few weeks after you’re infected and can last for up to four weeks.

Symptoms of primary HIV are similar to flu and include:

  • fever
  • swollen glands
  • sore throat
  • a rash on your body, which may spread to the palms of your hands and soles of your feet
  • painful muscles or joints
  • a headache
  • feeling generally unwell
  • ulcers in your mouth or around your anus
  • sweating at night

These symptoms aren't always caused by HIV, but if you have them and think you may have been infected with the virus, see your GP.

During this time, you're very infectious because the amount of the virus in your blood is high. This means that the risk of passing the infection on to someone else is high.

After these early symptoms, you may go through a period where you don’t have any symptoms and HIV can remain hidden for years.

Early HIV infection

After being infected, which may include symptoms of primary infection, there usually follows a period where you may have very few symptoms. This stage often lasts several years, but can be as short as a few weeks. During this time you may be more prone to getting skin infections, such as warts or fungal infections. If you're unaware of your HIV infection, there is a much greater risk that your body's ability to fight infection will become badly affected. You may start to get symptoms including:

  • a fever
  • weight loss
  • night sweats
  • persistent diarrhoea

Advanced HIV infection (AIDS)

Without treatment, most people will go on to develop advanced HIV infection (or AIDS). Eventually, you could be at risk of life-threatening illnesses that usually require treatment in hospital. These illnesses include:

  • tuberculosis
  • pneumonia
  • fungal infections
  • various types of cancer

It can take 10 to 15 years for AIDS to develop.

Causes of HIV/AIDS

Most people with HIV are infected during unprotected vaginal or anal sex. Not everyone who is exposed to HIV is infected with the virus, although it’s more likely if you have repeated sexual contact with someone who has HIV. There is a small chance of getting infected through unprotected oral sex, particularly if you have mouth ulcers or gum disease, and your partner ejaculates in your mouth.

HIV can also be passed on through direct contact with infected blood. For example, by using infected needles to inject drugs, piercings or tattoos, or from an accidental injury with a needle that contains infected blood.

The virus can be passed from a mother to her baby if she has HIV during pregnancy, childbirth or when breastfeeding. However, this can be prevented with medicines and bottle feeding your baby instead of breastfeeding.

In the past, some people were infected with HIV through blood or organ donations. All donations in the UK are now screened for HIV, so the chances of this happening are extremely low.

Other fluids in your body, such as saliva, sweat, or urine, don’t contain high enough levels of HIV to cause an infection. HIV can't be passed on through normal day-to-day activities, such as sharing cutlery, sitting on toilet seats or by shaking hands. And it can't be passed on through a mosquito bite or bites from other animals or insects.

Diagnosis of HIV/AIDS

It's important to see your GP or visit a sexual health clinic if you think you may have been infected with HIV. Being diagnosed soon after you’re infected can help you get the best out of the treatments.

Your GP will ask about your symptoms and examine you. He or she may also ask you about your medical and sexual history.

You will be asked to have a blood test to check for HIV antibodies (proteins produced by the immune system that fight against the virus). This can be in the form of a finger prick test, which can give a result within an hour, or your doctor may take blood from your arm and send the sample to a laboratory. It can take up to three months for HIV to show in your blood so you may need to have the test repeated.

Treatment of HIV/AIDS

There is no cure for HIV infection. However, treatment with anti-HIV medicines can reduce the amount of the virus in your body, slow down the damage the virus does to your immune system and reduce your chances of developing a life-threatening infection later on in life. When taken properly, anti-HIV medicines can help you to stay well and live a full life.

HIV treatment is managed at specialist out-patient clinics and it's important to attend all your appointments. Your health professional will check how well your immune system is working and will ask you about your general health at these appointments.

Usually, once the number of CD4 white blood cells has fallen to a low level, or if you become pregnant, your doctor will recommend starting treatment with medicines. You may also start treatment if you develop a serious infection or a condition linked to advanced HIV infection.


Medicines for HIV work in a number of different ways. For this reason, you will be asked to take a combination of different medicines together. This is known as antiretroviral therapy, combination therapy or highly active antiretroviral therapy (HAART). The medicines will prevent the virus from reproducing in your body and reduce the amount of virus in your blood, which will allow your immune system to recover. Medicines will also stop the virus from changing (mutating) when it reproduces.

There are several types of medicine. Combination therapies usually contain medicines from at least two different classes of drugs. Your doctor will advise you on the best medicines for you. Taking your medicine regularly and on time is particularly important otherwise the virus can become resistant to your medicine causing it to be less effective.

Always ask your GP or health professional for advice and read the patient information leaflet that comes with your medicine.

You may develop side-effects in the first few months after you start your treatment. Side-effects are the unwanted effects of taking a medicine. If you have side-effects, it's important to talk to your doctor or the healthcare professional who prescribed your medicine before you stop taking it. Side-effects may include:

  • feeling or being sick
  • diarrhoea or wind
  • feeling tired and aching muscles
  • a rash
  • trouble sleeping or bad dreams
  • dizziness

These side-effects should improve as your body gets used to the medicine. If they don’t, see your doctor to discuss other treatment options.

Certain HIV medicines can increase your risk of serious conditions, such as heart disease by causing high levels of cholesterol (fats) in your blood, so it’s important to see your doctor regularly to monitor any side-effects. Some of the side effects can be controlled by the use of other medicines.

Prevention of HIV/AIDS

You can greatly reduce the risk of getting, or passing on, HIV by always using a condom during sex. However, condoms can't completely eliminate the risk of HIV infection. Use a dental dam (a rectangular piece of latex that fits in your mouth) for oral sex.

If you reduce the number of partners you have, it will reduce your overall risk of getting infected with HIV. You may wish to have regular checks for sexually transmitted infections.

If you take intravenous drugs or inject medicines, don't share injection equipment and always use a fresh needle.

Post-exposure prophylaxis treatment

Post-exposure prophylaxis (PEP) is an emergency medicine treatment, which can reduce your chances of getting infected if you’re exposed to HIV, for example, if a condom breaks or if you’re a healthcare worker exposed to HIV. If you suspect you have been exposed to HIV, seek urgent medical attention.


Produced by Stephanie Hughes, Bupa Health Information Team, May 2012.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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