HIV prevention, testing and treatment

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  • What is HIV?
  • Preventing HIV
  • HIV testing
  • HIV Treatment

What is HIV?

What is HIV?

HIV stands for ‘human immunodeficiency virus’. It is an infection caused by a virus that attacks the body's immune system. In the UK, it is most commonly transmitted by having anal or vaginal sex without a condom.

‘Immunodeficiency’ refers to the damage caused to your immune system by the virus. Your immune system exists to fight infections and diseases. HIV makes your immune system weaker, so it is less able to protect you from illness and keep you well.

HIV can be treated by taking antiretroviral medication. Though it cannot be completely cured, effective treatment means you can live a long healthy life. If you start treatment early, after a few months you should have the virus under control. This means that you cannot transmit HIV to other people through sexual contact.

National guidelines recommend that people who are at risk of HIV infection should test regularly. A late diagnosis of HIV means the virus has had more time to weaken your immune system. An early diagnosis allows you to start treatment early.

Free HIV testing and treatment is available from the NHS to anyone in the UK.

Symptoms of HIV

Most people may not notice early symptoms, as they are much like a cold or flu and only last for a week or two.

Early symptoms of HIV may include:

  • sore throat
  • fever
  • body rash
  • tiredness
  • headache.

HIV symptoms in women and men are similar, although they may vary from person to person.

These cold-like symptoms appear between two and six weeks after infection and are known as a ‘seroconversion’ illness. Seroconversion is a signal that your immune system is reacting to a virus and has started to produce antibodies (a protein in the blood) to fight the viral infection. It is these antibodies that are detected by an HIV test.

After the seroconversion illness, the untreated virus will continue to damage your immune system, but you may not notice any other symptoms for years.

If you have a weakened immune system, your body is less able to prevent the development of cancers, which means people with HIV are more likely to get certain cancers.

AIDS is caused after untreated HIV has been present for so long that your immune system is too weak to fight most infections.

If you put off your test, the virus could be doing a lot of damage. Even if you do not have any symptoms of an STI, it's important to continue to get tested, as you may have an infection without knowing. You could also be passing the infection onto other people.

Some people are more likely to get HIV than others

Regular testing is highly recommended for certain groups of people who are at a higher risk of becoming infected:

  • men who have sex with men
  • black African heterosexuals
  • people who share drug taking equipment such as needles or syringes.

In the UK, the vast majority of people contract HIV through unprotected anal or vaginal sex.

The risk of catching it through unprotected oral sex is much lower, but is significantly higher if the person giving oral sex has bleeding gums, sores or ulcers. The virus is not transmitted through saliva but can be passed on through blood from these sores.

Of all HIV diagnoses in England in 2021:

  • 36% were in gay or bisexual men
  • 19% were in black African men or women
  • 2% contracted HIV through sharing injecting equipment.

Since 2000, the majority of new diagnoses in England have been in heterosexual people.

It has been estimated that more than 5,000 people in the UK are living with HIV without knowing and could be passing the virus on to others.

If you test positive for HIV, you should tell all of your current partners and anyone else that you have had sex with in the last three months. They may have contracted HIV and it is important for them to get tested. It can be difficult to talk to people about your diagnosis. If you’d like some support, reply to one of our text messages. Our clinical team are on hand to support you. If your clinic confirmatory test is positive, the clinic staff will advise you about confidential partner notification services.

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Preventing HIV

Regular testing

The only way to know whether you have HIV is to get tested. Our at home test kits allow you to safely take a blood sample at home.

The spread of HIV and other STIs would be reduced if everyone took a test every time they changed their sexual partner. Early diagnosis and treatment would prevent the infection from being passed on as often.

If you think you are at risk of HIV, you should test every three months. Read more in the when to test section.

You can access free HIV testing in sexual health clinics, General Practice surgeries (GPs) and A&E departments.

All pregnant women in the UK are offered a blood test as part of their antenatal screening which includes testing for:

  • HIV
  • syphilis
  • hepatitis B
  • rubella.

In England, it's rare for a pregnant woman living with HIV to pass the virus to her baby, provided she receives timely and effective HIV treatment and medical care. In 2017, all of the children diagnosed with HIV following mother-to-child transmission were born outside of the UK.

Use condoms and don’t share drug equipment

The most common way to contract HIV is by having sex without a condom. Certain bodily fluids are highly infectious in people who are living with the virus and are not on effective treatment:

  • blood
  • semen
  • vaginal discharge
  • anal secretions.

When using condoms, make sure you are not using an oil-based lubricant (for example, Vaseline or massage oil) as these can weaken the condom, meaning it is more likely to split. Water based lubricants or ‘lubes’ are easy to get hold of and do not weaken condoms. Lube is available from most pharmacies and sexual health clinics.

Sharing injecting equipment puts you are risk of catching HIV and other viruses such as hepatitis C.

If you use needles to inject drugs, steroids, hormones or silicone, never share any injecting equipment (needles, syringes, spoons or swabs).

Sharing water to wash or flush out needles can also lead to the transmission of HIV.

Infected blood can be injected and can pass on HIV whilst injecting into:

  • veins (intravenous)
  • fat under the skin (subcutaneous)
  • muscle (intramuscular).

Taking preventative medication or effective treatments

Pre-exposure prophylaxis (PrEP)

PrEP is a medication in tablet form that is taken by people who think they are at risk of catching HIV. There are very few side effects and it is highly effective at blocking the infection.

However PrEP won’t protect you from other STIs or an unwanted pregnancy, so it is still important to consider condom use and test for STIs every three months.

Find out more about PrEP and how to get it.

Post-exposure prophylaxis (PEP)

PEP is a short course of emergency anti-HIV medication which is taken to try to prevent infection after recent risk of exposure. It needs to be started within 72 hours (three days), but it is recommended that you start it as soon as possible, ideally within 24 hours. The sooner you take it, the more likely it is to be effective.

If you think you may have been exposed to HIV in the last three days, you should go to your local sexual health clinic or A&E immediately.

Antiretroviral therapy (ART)

If you are HIV+, taking antiretroviral medication (a highly effective treatment for HIV) is the best thing you can do to avoid passing HIV on to others. This treatment can reduce your viral load so that it becomes undetectable. This means you are unable to transmit HIV to other people. Read more about undetectable viral loads.

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HIV testing

When to test

This depends on the type of STI test you are doing. For our lab test, results are most accurate:

  • at least 7 weeks after potential exposure to HIV infection
  • at least 12 weeks after potential exposure to syphilis infection.

Our rapid self-tests for HIV are most accurate at least 12 weeks after potential exposure.

Our tests are mainly looking for antibodies that your body produces in response to infection. These take some time to be detectable. This period of time between sex and testing is known as a window period.

If you are unsure when you might have been exposed to infection, we recommend you test now and again after 12 weeks.

In 2021, 46% of HIV diagnoses in the UK were made at a late stage of HIV infection. This means people are testing many years after unprotected sex and potential exposure, when it is harder to treat the infection.

Late diagnosis was 63% in heterosexual men and 50% in heterosexual women. Among gay and bisexual men it was 37%. Late diagnosis of HIV reduces the effectiveness of treatment, so it's best to test early, and start treatment as soon as possible if you have a positive result.

Our home testing service is quick, free and confidential.

Reactive results

A ‘reactive’ result means that the test has reacted with something in your blood that could be (but is not necessarily) the HIV virus or antibodies to the HIV virus. A reactive result is not the same as a positive result.

Our NHS provider laboratory works to strict government enforced protocols to ensure results are as accurate as possible. Despite this, no STI test is 100% accurate. The same applies to any clinic that offers this kind of test. If you have a negative result, and you have tested 7 weeks after potential exposure with a lab test or 12 weeks after potential exposure with a rapid self-test (the window period), then you can be confident that you don’t have HIV.

It is also important to know that due to the sensitivity of the test, there are some other illnesses or infections that can cause a reactive result with an HIV test. This means that you could get a reactive result even if you do not have HIV. Anyone with a reactive result will need to visit a clinic for further testing on a larger blood sample. Between 6% and 35% of reactives will be confirmed as positive in a clinic.

Diagnosing HIV

The World Health Organisation’s guidance on HIV testing says that HIV can only be diagnosed after completing three separate blood tests. Each test is designed to look for three different parts of the HIV virus or its antibodies.

The sample you provide from your home test kit can only be tested once. This means if you have a reactive result from this first test, we will advise you to go to your local clinic so they can run the second and third tests. The first test is extra sensitive, to make sure that it does not miss HIV related proteins in your blood. Because it is so sensitive, it can also react with other proteins that are not HIV related. The second and third tests look for different parts of the HIV related proteins.

If there is a positive diagnosis of HIV after all three tests, you will be referred to a specialist HIV clinic to discuss your treatment options.

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HIV treatment

Taking antiretroviral medicines to treat HIV

If you are diagnosed with HIV, you will be prescribed antiretroviral medication. It works by stopping the virus from replicating. This protects your immune system from further damage and allows it to repair and strengthen itself.

The HIV virus can easily develop resistance to a single medicine, so for the treatment to be effective it is likely your doctor would prescribe a combination of different antiretroviral tablets.

During your treatment, it is vital that you take your recommended dose every day and that you always attend your HIV clinic appointments. Find out more about what to expect from HIV treatment clinic appointments.

HIV treatment is free to all in the UK regardless of immigration or residency status.

Having an undetectable viral load

The goal of HIV treatment is to have an undetectable viral load. This means the level of the virus in your body has dropped so low that is can no longer be detected in a test.

HIV treatment clinics commonly use two tests to measure how effective treatment is:

CD4 count: looks at how much your immune system is being impacted by the virus
Viral load: a measure of how much HIV is in the body.

If you have been taking effective HIV treatment and your viral load tests have come back undetectable for more than 6 months, it means you cannot pass the virus on through sex. This is called undetectable=untransmittable (U=U).

Other things you should do to stay well

As your immune system has been damaged by the virus, you'll be encouraged to reduce the likelihood of developing other serious illnesses by making lifestyle changes. This might include:

  • stopping smoking
  • having annual flu jabs
  • exercising regularly
  • eating a healthy diet.

You will also be encouraged to ask questions and discuss how you are feeling about your health, your diagnosis and your future. It is really important that you care for your mental health as well as your physical health. Your HIV clinic should be able to help you through this process or refer you to a specialist psychological support service.

If you have dietary needs, HIV clinics should be able to offer you appointments with a dietician. They can advise you if you are on treatment but are struggling to manage your weight, experience sickness or diarrhoea which makes eating difficult, or if you have been told to take tablets with certain foods.

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Myths & FAQs

How common is HIV in the UK?

The most recent estimate (2019) suggests there were just over 100,000 people living with HIV in the UK, including more than 5,000 undiagnosed people who are HIV positive.

People living in London, men who have sex with men, and black African people are disproportionately affected:

  • 22% of people with new diagnoses in England in 2021 were living in London
  • of the 2,023 people diagnosed in England in 2021, 36% were gay or bisexual men
  • of the 798 heterosexual people diagnosed with HIV in England in 2021, 37% were black African men and women.

Will I die young if I am diagnosed with HIV?

Antiretroviral treatments are becoming more and more effective. That means that life expectancy for people living with HIV is improving.

There is still no cure, but with the introduction of combination antiretroviral treatment people with the virus are much more likely to live a long and healthy life.

Can I get HIV from kissing?

HIV cannot be transmitted through:

  • kissing
  • spitting
  • sneezing
  • coughing
  • general social contact.

This is because the virus does not survive for very long outside the body.

HIV can be passed on through:

  • blood
  • semen
  • vaginal fluid
  • anal mucus
  • breast milk.

Find out more about how to avoid contracting HIV.

Can HIV be passed on to my baby?

It is possible for HIV to pass from a woman to her baby during pregnancy, labour or birth. It can also be passed on through breastfeeding.

However, the chances of passing on the infection to your baby can be reduced almost to zero by:

  • taking anti-HIV medication during pregnancy and around the time of birth
  • providing a short course of anti-HIV medication to your baby in the period immediately after birth.

It is important to discuss your HIV infection with your obstetrician as it will affect the decisions that you make about labour and delivery. Bottle feeding rather than breastfeeding can also help to prevent the virus from passing from mother to child.

If you are living with HIV and you are thinking about having a baby, talk to your doctor about how to reduce the risk of passing on the infection to your baby or your partner.

All pregnant women in the UK are tested for HIV as part of their routine antenatal appointments. If you are diagnosed with HIV during your pregnancy, you will be referred for treatment at an early stage. Your doctor will discuss options for delivering your baby and advise you about whether your baby will need any treatment after it has been born.

Can HIV be passed through menstrual (period) blood?

Yes. If a woman has HIV and still has a detectable viral load, her menstrual blood also carries a risk of transmission.

Find out about how to gain an undetectable viral load through antiretroviral medication.

If I take PrEP am I safe?

In clinical trials PrEP has been proven to be very effective protection against HIV when used in these two ways:

  • taken daily, or
  • only taken when needed (two tablets 2-24 hours before sex, one tablet 24 hours and 48 hours after sex). This is known as ‘event-based dosing’.

If you are thinking of buying your PrEP online, it is important you attend your local sexual health clinic for regular health checks and STI screens, as PrEP does not protect you from other STIs.

Although PrEP is a very safe medication with very few side effects, some (particularly older) men need to keep a close eye on their liver (renal) function, and in some cases lower their PrEP dose to event-based.

Find out more about PrEP on I want PrEP now.

How does the home HIV test work?

Our tests look in your blood sample for a protein or an antibody made by your immune system to fight HIV.

Is HIV testing free? is commissioned to provide free home test kits to people in England only. Whether you can get a free kit or not depends on whether your local authority is funding this particular service.

There are lots of other places to get tested: sexual health clinics, GP surgeries or A&E departments. The NHS provides free and confidential testing for everyone in the UK, regardless of immigration or residency status.

What does HIV positive (HIV+) mean?

People who have been diagnosed with HIV are called HIV positive (sometimes written HIV+).

What happens at HIV treatment clinics?

You will have two to four regular appointments a year at your HIV clinic to make sure your treatment is working properly and that you are well.

Regular blood tests will check your CD4 count, your viral load, liver health and screen for STIs.

Your urine may sometimes be tested to check for diabetes and the health of your kidneys.

How often you need tests or appointments will depend on how long you have been on treatment, how well you are and whether you are pregnant.

What are the symptoms of later HIV-related illnesses?

Some people may notice flu-like symptoms a few weeks after infection. After this, HIV infection usually causes no symptoms at all for many years. If untreated, the virus will continue to weaken your immune system and you may start to experience symptoms that might seem like other illnesses. These symptoms usually happen many years after infection, once your immune system has been significantly damaged. They may include:

  • dramatic weight loss
  • night sweats
  • thrush in the mouth
  • swollen glands in the groin, neck or armpit
  • long-lasting diarrhoea
  • tiredness.

A weakened immune system can also leave you more susceptible to other serious infections such as:

  • tuberculosis (TB)
  • pneumonia
  • some cancers.

What does U=U mean?

U=U stands for undetectable equals untransmittable. It is a hugely influential campaign based on a solid foundation of scientific evidence.

Individuals with HIV who take antiretroviral therapy (ART) and have achieved and maintained an undetectable viral load cannot sexually transmit the virus to others.

Campaign messaging is designed to challenge social stigma and fear around transmission, build self-esteem of individuals with HIV and continue to improve the treatment of HIV infection.

Find out more about U = U.

What is AIDS?

AIDS stands for acquired immune deficiency syndrome. If you have HIV and leave the virus untreated you can experience such a high level of damage to your immune system that you can develop AIDS.

The HIV virus can be transmitted from one person to another, whilst AIDS cannot. AIDS is developed inside your body after a prolonged period of living with untreated HIV.

You can’t get an AIDS diagnosis unless you’re already HIV positive.

So long as HIV is diagnosed early and treated effectively, it is unlikely that you will develop any AIDS related illnesses. It is more likely that you will live a long and healthy life.

How common is AIDS?

The UK continues to see a decline in AIDS related deaths as the provision of antiretroviral (ART) treatment for HIV positive people continues to improve.

However late diagnosis is still a cause for concern. A late diagnosis means that the person has been living with HIV without knowing and their immune system has been severely weakened by the time they are able to start treatment. These people are at risk of developing AIDS.

Testing regularly will significantly reduce your risk of ever developing AIDS.