HIV stands for Human Immunodeficiency Virus.

Once someone acquires HIV, the virus remains in their body for the rest of their life. If someone’s tested and found to be infected with HIV, they’re said to be HIV positive or living with HIV.

There’s currently no cure for HIV. However, treatment enables most people with HIV to live a long, healthy life, especially if they’re diagnosed soon after being infected.

HIV can be transmitted in a number of ways, all of which can be prevented. This information is mostly about sexual transmission.

Many people living with HIV have no obvious signs and symptoms. 2 in 5 people in the UK newly diagnosed with HIV are diagnosed late – this means they’ve been living with undiagnosed HIV for a number of years.

Up to 9 in 10 people who acquire HIV will have some symptoms soon after infection. This is known as seroconversion illness and can include fever, rash, headache, feeling generally unwell, aches and pains, mouth ulcers, sore throat, night sweats, weight loss, tiredness, swollen glands, and illnesses like meningitis. Not everyone has these symptoms and they’re easily mistaken for flu or other common illnesses.

After the first few weeks of infection, most people living with HIV will live for years without any signs or symptoms. If it’s not treated, HIV will eventually damage a person’s immune system until they start to develop serious illnesses or infections.

How will I know if I've acquired HIV?

You can only be certain you’re HIV positive if you have a test. If you or a partner think you might have become HIV positive, it’s important that you don’t delay seeking advice and getting a test.

Even if you don’t have symptoms, an HIV test is advised every time one of the following applies:

  • you, or a partner, have another sexually transmitted infection
  • you’ve recently had vaginal or anal sex without a condom with a new partner
  • a sexual partner tells you they’re living with HIV
  • you’ve shared needles or injecting equipment
  • you’re pregnant or planning a pregnancy.

Regular testing is advised if you’re from a population that’s more affected by HIV.

If you’re unsure about your HIV status, there are services you can go to for a test, advice and information.

HIV is a virus. When someone acquires HIV, the virus weakens and damages their body’s defence system (the immune system) so that it can’t fight off infections.

If someone’s immune system is damaged by HIV, they may develop one or more serious infections and illnesses, called AIDS-defining illnesses.

Sometimes this is called an AIDS diagnosis. AIDS stands for acquired immune deficiency syndrome but the term isn’t used very often now. Late-stage or advanced HIV is sometimes used instead.

People living with HIV who are diagnosed early enough and have effective treatment, won’t go on to develop an AIDS-defining illness.

HIV can be transmitted from one person to another through sexual contact, and in a limited number of other ways.

In the UK, more than 9 in 10 newly diagnosed people have acquired HIV through sexual transmission.

HIV can be transmitted during sex when the blood, semen (cum), pre-ejaculate (pre-cum), vaginal or anal fluids of an infected person enter the body of an uninfected person, most commonly by:

  • having vaginal or anal sex without using a condom
  • sharing sex toys.

A person living with HIV can have treatment to make the virus undetectable in their blood. This means they can’t transmit the virus to sexual partners (see below, How do I prevent HIV transmission during sex?).

HIV can also be transmitted by sharing needles and other injecting equipment.

If you’re pregnant and living with HIV, it’s possible to transmit the virus to the baby before or during birth, or by breastfeeding. This isn't common in the UK as transmission can be prevented with HIV treatment and by avoiding breastfeeding.

You can’t acquire HIV from hugging, saliva, kissing, sneezes, coughs, sharing baths or towels, from swimming pools, toilet seats or from sharing toothbrushes, razors, cups, plates or cutlery. You can’t acquire HIV from any animals or insects, including mosquitoes. HIV isn’t transmitted through biting.

Can HIV be acquired when receiving healthcare in the UK?

It’s extremely rare to become infected with HIV when receiving healthcare in the UK. All health professionals in the UK – such as dentists, doctors, midwives and nurses – must follow infection control procedures when caring for any patient.

In the UK, organ donors and blood from blood donors are tested to reduce the risk of HIV being transmitted through infected blood, blood products or donated organs. There have been no new cases of HIV due to blood donation in the UK for more than 10 years.

Some countries don’t have the same standards of medical and dental care as the UK, so there may be a risk of HIV transmission from infected blood products or un-sterile medical equipment if you receive healthcare in another country.

Are certain populations more affected by HIV?

Anyone can acquire HIV. You don’t need to have lots of sexual partners.

Overall, fewer than 2 in 1,000 people in the UK are living with HIV, but some populations are affected more than others.

If one of the following applies to you, and you’re sexually active, you’re at more risk of acquiring HIV than the overall population. You’re advised to have regular HIV tests.

  • Men who have sex with men (MSM). Around 1 in 17 MSM in the UK (around 1 in 7 in London) are living with HIV. Of these, more than 1 in 10 are unaware of their HIV infection.
  • Heterosexual (straight) black African people. Around 1 in 23 heterosexual black African women and 1 in 45 heterosexual black African men are living with HIV. Of these, around 1 in 10 are unaware of their HIV infection.
  • People from countries with high rates of HIV.

How do I prevent HIV transmission during sex?

People who know they’re living with HIV can access treatment which suppresses the virus in their body. This is known as having an undetectable viral load or having an undetectable HIV status.

This means they can’t transmit HIV to others and is called ‘treatment as prevention’ (TasP).

Most new HIV infections happen when a person acquires HIV from someone who isn’t aware they’re living with the virus. If you’re at risk of acquiring HIV, regular testing can help keep you and your sexual partner(s) healthy.

The following measures can help prevent HIV transmission during vaginal or anal sex.

  • An external condom or internal condom. For anal sex, it’s very important to use water-based or silicone-based lubricant to reduce the risk of the condom tearing.
  • Treatment as prevention (when you’re sure a partner living with HIV has achieved and maintained an undetectable viral load).
  • Pre-exposure prophylaxis (PrEP) (see below, What is PrEP?).

Condoms are the only measure that will also help protect you from other sexually transmitted infections (STIs).

HIV can be transmitted by oral sex (going down, giving head) but the risk is much lower than from unprotected (without a condom) vaginal or anal sex. Condoms or dams (latex or plastic squares) can help protect you from HIV and other STIs
during oral sex.

What's PrEP and can I get it to prevent HIV?

If you're HIV negative, pre-exposure prophylaxis (PrEP) may be suitable for you to reduce your risk of getting HIV. PrEP is available as a tablet, which you take before and after you have sex and are exposed to HIV.

Read our PrEP page to find out more.

What's PEP and how soon do I need to use it to prevent HIV?

Post-Exposure Prophylaxis (PEP) involves taking HIV treatment within three days (72 hours) of exposure to HIV, to prevent infection. A course of HIV treatment is taken for four weeks. It’s more effective the sooner you take it.

PEP is an emergency treatment. It’s usually only given if you’ve had sex without a condom in the following situations:

  • anal or vaginal sex with someone who’s HIV positive and not taking treatment, or if the virus is currently detectable in their blood
  • anal sex, where you were the receptive partner, with someone who has a high chance of having HIV but hasn’t recently been tested.

PEP may also be given in some other situations such as after a sexual assault.

You can get PEP at a sexual health or genitourinary medicine (GUM) clinic or an accident and emergency (A&E) department. A doctor or nurse will ask you some questions to find out if PEP is suitable for you.

What’s an HIV test?

An HIV test checks your blood for HIV antibodies and antigens to see whether the virus is in your body. Antibodies are substances made by your immune system to try and fight the infection. Antigens are a part of the virus.

Cervical screening tests, routine blood tests and swabs won’t detect HIV infection. If you’re not sure whether you’ve been tested for HIV, just ask.

How soon after transmission can I have an HIV test?

It takes time after you become infected with HIV for there to be enough antibodies or antigens in your blood to show up on an HIV test.

This time is sometimes called the ‘window period’. The length of the window period depends on the type of test you take. For tests where blood is taken from your arm and sent away to analyse, the window period is up to one month.

For tests which take a spot of blood from your finger, the window period can be from 4-12 weeks.

It’s important not to delay getting a test if you think you might have been exposed to HIV.

Anyone can have a test even if you don’t have any signs and symptoms. If the test shows you don’t have HIV but you’ve only recently been at risk, you might be advised to have a follow-up test to confirm the result.

What does an HIV test involve?

An HIV test usually involves taking a sample of blood from your arm and sending it to a laboratory to be tested.

It’s also possible to test for HIV using a spot of blood from your finger (made with a pinprick).

Where can I get an HIV test?

There are a number of services you can go to. You can also use a self-sampling kit or a home test. Choose the one you feel most comfortable with.

An HIV test can be done at:

  • a sexual health clinic or genitourinary medicine (GUM) clinic
  • some contraception clinics and young people’s services
  • private clinics (for a fee).

GP surgeries should offer you a test when you register. They may offer one at other times, or you can ask them to provide a test.

People who inject drugs may be able to get a test through a local drugs service.

Antenatal services and some gynaecology services will offer a test.

In some areas, testing is done by trained staff in places such as nightclubs, community events and churches.

If you’re concerned that you may have been exposed to HIV, don’t wait to be offered a test. Go to a clinic and ask for a test, or get a self-sampling or self-test kit.

Self-sampling tests

Self-sampling tests are available for free in some areas (see You can also buy them from online pharmacies. You take your own blood sample (self-sampling) and send it to the service to be tested.

If you choose to buy a kit, check it has a CE mark and is licenced for sale in the UK.

Home self-tests

You can buy an HIV self-test online which can give you your result in around 15 minutes (see You take a blood sample and test it yourself.

If you’ve become HIV positive in the last three months a self-test might not be able to detect the infection (see above, How soon after transmission can I have an HIV test?). If you think you’ve been exposed to HIV in the last three months then ask for a test from a sexual health clinic.

If you use a self-sampling test or self-test you’ll get instructions to help you. Make sure you read the information in full. If you have any questions, ring the telephone number included or call the National Sexual Health Helpline on 0300 123 7123.

How soon will I get the test result?

This depends on where you had the test. If you were tested at a clinic or other service, the doctor, nurse or health adviser will tell you when the result will be available. At most services the result should be available within a week; some may be earlier.

Some clinics and local testing services also offer rapid HIV testing from a spot of blood from your finger. This is when you’re given the result in a short space of time (often within a few minutes).

The test result will be either negative (no HIV antibodies detected) or reactive (HIV antibodies detected). A reactive result is sometimes called a positive result but this doesn’t necessarily mean you’re HIV positive. If you have a reactive result another test will be done at a clinic (where they’ll take blood from your arm) to confirm whether it’s a positive result.

If you used a self-sampling kit, the service will contact you with the results. They’ll advise you whether any treatment is needed and whether you also need to visit a clinic in person.

If you used a home self-test you’ll get the result in around 15 minutes. The test result will be either negative (no HIV antibodies detected) or reactive (HIV antibodies detected). If you have a reactive result you’ll need to have another test at a clinic (where they’ll take blood from your arm) to confirm whether it’s a positive result.

If you choose a self-test it’s important to think about how you might feel and what support you might need if your test is reactive.

How accurate are the tests?

No tests are 100% accurate, but HIV tests should pick up almost all HIV infections if done at the right time. All positive HIV tests are repeated to confirm the result. If your test result is negative, and you haven’t been exposed to HIV in the three months before the test, you can be confident you didn’t have HIV at the time of the test.

Will I have to pay for tests and treatment?

HIV testing is available on the NHS free of charge to anyone. In some areas, self-sampling tests (see above, Where can I get an HIV test?) can be ordered free online. You can also choose to buy self-sampling and self-test kits.

Anyone living in England is entitled to free HIV treatment on the NHS. HIV treatment is also available on the NHS in Scotland, Wales and Northern Ireland.

What’s the treatment for HIV?

If HIV is diagnosed, you’ll be referred to a specialist HIV clinic. The clinic will do blood tests to monitor the stage of the infection and you’ll be offered treatment straight away.

At first, you’ll attend the clinic every few months, but once you’re settled on treatment you’ll only need to go twice a year.

At the moment there’s no cure for HIV. The aim of treatment is to keep the level of HIV in your blood as close to zero as possible, so it can’t harm your immune system. When the level of virus is so low that a test can’t detect it, this is known as an undetectable viral load and is the best result you can get from treatment. This helps keep you healthy and means you can’t transmit the virus to anyone else.

The earlier that HIV is diagnosed and treatment started, the more successful it’s likely to be at keeping you healthy.

Your HIV clinic can give you full information about the best treatment options for you, possible side effects and long-term effects of treatment.

HIV support organisations can also provide this information.

During pregnancy, treatment can be given to prevent the virus being transmitted to the baby.

What happens when HIV isn’t treated?

It’s important that HIV is treated and monitored by specialist doctors and nurses.

Untreated HIV will cause long-term damage to your health. Eventually, it can develop into late-stage HIV infection, which can lead to death.

This may happen more quickly in some people than others, so if you’ve been at risk of HIV it’s important to get tested so you can begin treatment if you have the virus.

You don’t have to share your HIV status if you don’t want to. It may take some time to adjust to living with HIV.

Staff at your HIV clinic can support you to tell partner(s) when you’re ready, including support with talking to a current or long-term partner about your diagnosis.

It’s important that your current sexual partner(s) and any other recent partners are tested. The staff at the clinic can discuss with you which recent partners may need to be tested and help you contact them. This is called partner notification. They’ll be sent a message to say they may have been exposed to a sexually transmitted infection and suggest they go for a check-up. It may or may not say what the infection is. The message won’t have your name on it, so your confidentiality is protected.

Will I know how long I’ve been living with HIV?

An HIV test can’t tell you how long you’ve been living with the virus. If you feel upset or angry about having HIV and find it difficult to talk to a partner, family or friends, don’t be afraid to discuss how you feel with the staff at your clinic or a support organisation.

Does anyone else need to know I’ve had an HIV test?

Information about your HIV test should only be given to someone else with your permission. Talk to the doctor or nurse if you’re concerned about your results being kept confidential.

Can I have children if I’m living with HIV?

Yes. In the UK less than 1 in 100 babies born to people living with HIV during their pregnancy acquire the infection, due to treatment during pregnancy and avoiding breastfeeding.

It’s possible for people living with HIV to conceive a child with an HIV negative partner without transmission occurring. Your HIV clinic can give you advice on this.

If you’re living with HIV and could get pregnant, your clinic will support you with your reproductive health choices and with the pregnancy and birth if you decide to have children.

What happens if I’m pregnant and find out I’m HIV positive?

During your antenatal care, you’ll be offered an HIV test. If you’re HIV positive, you’ll be referred to a specialist HIV clinic. The staff will help you understand the diagnosis and take immediate steps to prevent the baby acquiring HIV during your pregnancy. They’ll continue to support you through your pregnancy, birth and beyond.

You’ll be advised to avoid breastfeeding as this may transmit the virus to the baby. If you feel strongly that you want to breastfeed, your clinic can discuss the benefits and risks with you, and support is available.

Aidsmap has more information on having a baby when you’re
living with HIV

    It's possible to get a sexually transmitted infection (STI) by having sex with someone who has an STI, even if they have no symptoms.

    The following measures will help protect you from HIV and most other STIs.

    If you have a sexually transmitted infection they’ll also help prevent you from passing it on to someone else.

    • Use external condoms or internal condoms every time you have vaginal or anal sex. How to use condoms.
    • Standard condoms are suitable for anal sex. It’s important to use a water-based or silicone-based lubricant for anal sex to reduce the risk of the condom tearing.
    • If you have oral sex (going down, giving head), use a condom to cover the penis, or a dam (a latex or soft plastic square) to cover the vulva (external female genitals) or anus.
    • Avoid sharing sex toys. If you do share them, wash them or cover them with a new condom before anyone else uses them.
    • If you can, avoid using spermicidally lubricated condoms. The spermicide commonly contains a chemical called Nonoxynol 9 which may increase the risk of HIV infection.

    For more information and support visit:

    Information last updated:
    Next planned review by:

    This website can only give you general information. Our HIV information is based on evidence-based guidance produced by the British HIV Association (BHIVA), the British Association for Sexual Health and HIV (BASHH) and Public Health England (PHE), with the kind assistance of NAT (National AIDS Trust).

    If you’d like information on the evidence used or would like to give feedback, email

    Contact your doctor, practice nurse or a clinic if you're worried or unsure about anything.