Most people who are infected with HIV experience a short, flu-like illness that occurs two to six weeks after infection. After this, HIV often causes no symptoms for several years.

The flu-like illness that often occurs a few weeks after HIV infection is also known as seroconversion illness. It's estimated that up to 80% of people who are infected with HIV experience this illness.

The most common symptoms are:

• fever (raised temperature)
• sore throat
• body rash

Other symptoms can include:

• tiredness
• joint pain
• muscle pain
• swollen glands (nodes)

The symptoms, which can last up to four weeks, are a sign that your immune system is putting up a fight against the virus. 

These symptoms can all be caused by conditions other than HIV, and do not mean you have the virus.

However, if you have several of these symptoms, and you think you have been at risk of HIV infection, you should get an HIV test.

After the initial symptoms disappear, HIV will often not cause any further symptoms for many years.

During this time, known as asymptomatic HIV infection, the virus continues to spread and damage your immune system. This process can take about 10 years, during which you will feel and appear well.

Want to know more?

• Terrence Higgins Trust: Stages of HIV infection

Late-stage HIV infection

If left untreated, HIV will weaken your ability to fight infection so much that you become vulnerable to serious illnesses.

This stage of infection is known as AIDS, although doctors now prefer to use the term late-stage HIV infection.

Typically, a person with late-stage HIV infection has:

• persistent tiredness
• night sweats
• weight loss
• persistent diarrhoea
• blurred vision
• white spots on the tongue or mouth
• dry cough
• shortness of breath
• fever of above 37C (100F) that lasts a number of weeks
• swollen glands that last for more than three months

At this stage, you are at increased risk of life-threatening illnesses such as tuberculosis, pneumonia and some cancers. Many of these, though serious, can be treated and your health is likely to improve if you start HIV treatment.

Read more about treating HIV.