AIDS

Symptoms of HIV and AIDS

Not everyone notices symptoms when they first catch HIV, but many people develop a short flu-like illness 2–4 weeks after infection. This usually clears up within 1–2 weeks, so it's easily mistaken for a different bug, and can include:

• a high temperature
• swollen, tender glands
• a sore throat
• a blotchy rash, often on your chest or back
• headaches and tiredness
• mouth or genital sores, or an upset stomach.

After this, HIV usually moves into a much longer phase with few or no symptoms at all. This stage can last from around 3 years to more than 20 years without treatment (on average around 8 years), which is why many people don't know they have HIV until much later.

If HIV is left untreated for long enough, it damages your immune system so severely that you develop AIDS. At this stage, you become more vulnerable to infections and illnesses that a healthy immune system would normally fight off, alongside symptoms such as:

• long-lasting fevers, night sweats and chills
• swollen glands
• extreme tiredness and weakness
• unexplained weight loss
• persistent diarrhoea, which affects around 90% of people with AIDS
• an increased risk of certain infections and cancers.

Causes and risk factors

AIDS is caused by ongoing, untreated infection with HIV. You catch HIV when the virus passes from someone who has it into your bloodstream, most often through:

• unprotected vaginal, anal or oral sex, with anal sex carrying the highest risk
• sharing needles or other injecting equipment
• blood transfusions or medical procedures using unscreened blood, mainly a risk where screening is limited
• a mother passing it to her baby during pregnancy, birth or breastfeeding.

HIV is not passed on through everyday contact. It cannot survive in saliva, sweat, tears, urine or faeces unless these are contaminated with blood, so you cannot catch it from sharing cups or cutlery, hugging, or using the same toilet as someone with HIV.

Certain factors raise your risk of catching HIV. Having another sexually transmitted infection that causes genital ulcers can increase your risk around five-fold, and your risk is also higher if you have condomless sex with multiple partners or share injecting equipment. Healthcare workers face a small additional risk from needle-stick injuries, though this risk is low.

Globally, some groups are more affected by HIV than others, including men who have sex with men, people who inject drugs, sex workers and transgender people. Public health campaigns increasingly focus on supporting these groups with testing, prevention and treatment, since social stigma and unequal access to services still hold many people back from getting tested.

Types of HIV

There are two types of the virus that can lead to AIDS: HIV-1 and HIV-2. HIV-1 is far more common worldwide and is responsible for the vast majority of infections, while HIV-2 is much less easily passed on and is mostly found in West Africa.

Doctors also describe HIV infection in three stages:

1. An early, flu-like illness soon after infection
2. A much longer phase with few or no symptoms
3. AIDS itself, once the immune system has been severely weakened. Reaching this final stage isn't inevitable, since starting treatment early usually stops the infection ever progressing this far.

Diagnosing HIV and AIDS

HIV is diagnosed using a blood test. Most tests look for antibodies your body makes in response to the virus, though it can take 3–12 weeks after infection for these to build up to detectable levels, sometimes called the window period.

If you might have been exposed very recently, a different type of test that looks for the virus itself, rather than antibodies, can sometimes pick up an infection earlier. Any positive result is always confirmed with a second, different test before you're given a diagnosis.

A diagnosis of AIDS specifically is made once your CD4 count (a measure of key immune cells in your blood) falls below 200 cells per microlitre, or once you develop certain infections or illnesses linked to a severely weakened immune system.

Treatment for HIV and AIDS

There's no cure for HIV, but treatment is highly effective at controlling the virus and preventing AIDS from ever developing. Treatment is recommended as soon as you're diagnosed, whatever your CD4 count, and is normally continued for life without breaks.

The main treatment is a combination of medicines called antiretroviral therapy (ART), usually made up of at least three drugs from at least two different drug classes. Most people take this as one or more tablets a day, although longer-acting injections, given every 1–2 months, are now becoming more widely available, including through the NHS.

The goal of treatment is to reduce the amount of virus in your blood to an undetectable level. Once your viral load is undetectable, you stay healthier for longer, and you also have effectively no risk of passing HIV on to a partner through sex, an approach often summed up as Undetectable = Untransmittable, or U=U.

If you develop AIDS, your treatment will also aim to prevent and treat the infections and cancers that come with a severely weakened immune system, alongside your antiretroviral therapy. This might include specific antibiotics, antifungal medicines or vaccinations, depending on what you're at risk of.

When to get tested or see a doctor

See a doctor, sexual health clinic, or contact NHS 111 as soon as possible if you think you might have been exposed to HIV, for example through condomless sex or a shared needle. Starting emergency medicine called post-exposure prophylaxis (PEP) within 48 to 72 hours of a possible exposure can stop the infection taking hold, so don't wait to see if symptoms develop.

You should also get tested if you develop a flu-like illness that doesn't have an obvious cause, particularly after a possible exposure, or if you've never been tested and think you could be at risk. Testing is quick and confidential, and it's the only way to know your HIV status for certain.

If you're at ongoing higher risk of HIV, ask your doctor or sexual health clinic about regular testing and about PrEP, a daily medicine that can reduce your chance of catching HIV by around 99% during sex.