top of page

About HIV and AIDS

While there is no cure for HIV, there are very effective treatments that enable most people with the virus to live a long and healthy life

NHS logo.png
Looking for a sexual health clinic?

Sorry, Mildmay is an inpatient-only hospital and we don't have a walk-in clinic, but you use this link to find your nearest service.

Undetectable = Untransmissable

When a person is living with HIV and is on effective treatment, it lowers the level of HIV (the viral load) in the blood. When the levels are extremely low (below 200 copies/ml of blood measured) it is referred to as an undetectable viral load. This is also medically known as virally suppressed. At this stage, HIV cannot be passed on sexually.

This scientific evidence was gathered from several studies. The studies included thousands of heterosexual and gay couples in which one partner had HIV and the other did not. Over the course of the studies, they found that there was not a single HIV transmission from an HIV-positive partner who had an undetectable viral load.

For many people living with HIV, the news that they can no longer transmit HIV sexually is life-changing. In addition to being able to choose to have sex without a condom, many people living with HIV who are virally suppressed feel liberated from the stigma associated with living with the virus. The awareness that they can no longer transmit HIV sexually can provide people living with HIV with a strong sense of being agents of prevention in their approach to new or existing relationships.


What are HIV and AIDS?

HIV and AIDS are two different things: HIV is the virus, while AIDS is the collection of illnesses caused when HIV is left untreated and weakens the immune system.

HIV- Human Immunodeficiency Virus

HIV attacks the body’s immune system gradually causing damage. Without treatment, the immune system will become too weak to fight off illness and infection.

There is currently no cure for HIV. But major advances in treatment mean that many people can lead long and healthy lives, although some may experience side effects from the treatment.

HIV is present in blood, genital fluids (semen, vaginal fluids and moisture in the rectum) and breast milk.

AIDS- Acquired Immune Deficiency Syndrome

AIDS is the term used to describe a stage of HIV infection when the body is too weak to fight off a range of diseases.

You cannot catch AIDS. HIV causes AIDS and it is HIV that can be passed on. Being diagnosed with AIDS means different things for different people.

What are HIV & AIDS

Just because someone has AIDS does not mean they will die – but it is essential to have medical care and treatment.

The main ways HIV can be passed on

In the UK, most cases of HIV are caused by having sex with a person who has HIV without using a condom.

A person with HIV can pass the virus on to others even if they don't have any symptoms. People with HIV can pass the virus on more easily in the weeks following infection.

HIV treatment significantly reduces the risk of someone with HIV passing it on.

Sexual contact

Most people diagnosed with HIV in the UK acquire the virus through unprotected vaginal or anal sex.

It may also be possible to catch HIV through unprotected oral sex, but the risk is much lower.


The risk is higher if:

  • the person giving oral sex has mouth ulcers, sores or bleeding gums

  • the person receiving oral sex has recently been infected with HIV and has a lot of the virus in their body, or another sexually transmitted infection.

Other risk behaviours

Other ways of getting HIV include:

  • sharing needles, syringes and other injecting equipment 

  • from mother to baby before or during birth or by breastfeeding

  • sharing sex toys with someone infected with HIV

  • healthcare workers accidentally pricking themselves with an infected needle, but this risk is extremely low

  • blood transfusion – now very rare in the UK, but still a problem in developing countries.

The main ways HIV can be passed on

How HIV is transmitted

HIV isn't easily passed on from one person to another. The virus doesn't spread through the air like cold and flu viruses.

HIV lives in the blood and in some body fluids. To get HIV, one of these fluids from someone with HIV has to get into your blood.

The body fluids that contain enough HIV to infect someone are:

  • semen

  • vaginal fluids, including menstrual blood

  • breast milk

  • blood

  • lining inside the anus


Other body fluids, like saliva, sweat or urine, don't contain enough of the virus to infect another person.


The main ways the virus enters the bloodstream are:


  • by injecting into the bloodstream with needles or injecting equipment that's been shared with other people

  • through the thin lining on or inside the anus, vagina and genitals

  • through the thin lining of the mouth and eyes

  • through cuts and sores in the skin

How HIV is transmitted

But there are ways of preventing HIV infection in all of these situations.

There are many effective ways to prevent or reduce the risk of HIV infection. Speak to your local sexual health clinic or a GP for further advice about the best way to reduce your risk.

HIV isn't passed on through:

  • spitting

  • kissing

  • being bitten

  • contact with unbroken, healthy skin

  • being sneezed on

  • sharing baths, towels or cutlery

  • using the same toilets or swimming pools

  • mouth-to-mouth resuscitation

  • contact with animals or insects like mosquitoes

Preventing HIV infection

Symptoms of HIV

These vary from person to person, People can live with HIV for years before having any symptoms. The only way to be sure if you have HIV is to have an HIV test. You cannot tell from symptoms alone.

Fever and chills

Rainbow body.png

Headaches and mood swings

Pneumonia, cough with phlegm, shortness of breath, and chest pain

High heart rate and low blood pressure

Clamminess, rashes and blueness of the skin

Women: changes in menstruation,. lower belly pain and vaginal yeast infection (later stages of infection)

Sore throat, swollen lymph nodes and mouth ulcers

Muscle fatigue and aches

Nausea, vomiting and loss of appetite

Joint pain

However, most people infected with HIV experience a short, flu-like illness that occurs 2-6 weeks after infection. After this, HIV may not cause any symptoms for several years.

It's estimated up to 80% of people who are infected with HIV experience this flu-like illness.

Symptoms of HIV

The most common symptoms are:

  • raised temperature (fever)

  • sore throat

  • body rash

Other symptoms include:

  • • tiredness
    • joint pain
    • muscle pain
    • swollen glands

The symptoms usually last 1-2 weeks, but can be longer. They're a sign that your immune system is putting up a fight against the virus.

But having these symptoms does not necessarily mean you have the HIV virus. Remember: they're commonly caused by conditions other than HIV.

If you have several of these symptoms and think you've been at risk of HIV infection within the past few weeks, you should get an HIV test.

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

During this time, the virus continues to be active and causes progressive damage to your immune system.

This process can vary from person to person, but may take up to 10 years, during which you'll feel and appear well.

Once the immune system becomes severely damaged, symptoms can include:


  • weight loss

  • chronic diarrhoea

  • night sweats

  • skin problems

  • recurrent infections

  • serious life-threatening illnesses

Earlier diagnosis and treatment of HIV can prevent these problems.

Rapid HIV Test being administered

Why take an HIV Test?

You should still take an HIV test if you may have been at risk at any time in the past, even if you do not experience any symptoms.


The sooner you’re diagnosed with HIV, the sooner you can start treatment.

Antiretroviral drugs(ARVs) will keep the virus under control by stopping it from reproducing itself. The goal is to keep levels of HIV so low that in tests the person has an undetectable viral load.

If someone with HIV is on effective treatment and has an undetectable viral load they cannot pass on HIV.

Find out more on the Terrence Higgins Trust (THT) website.

Terrence Higgins Trust is the UK's leading HIV and sexual health charity.

There are now many quick and convenient ways to test for HIV

You should still take an HIV test if you may have been at risk at any time in the past, even if you do not experience any symptoms.


The sooner you’re diagnosed with HIV, the sooner you can start treatment.

Antiretroviral drugs(ARVs) will keep the virus under control by stopping it from reproducing itself. The goal is to keep levels of HIV so low that in tests the person has an undetectable viral load.

If someone with HIV is on effective treatment and has an undetectable viral load they cannot pass on HIV.

More information about HIV and how to get tested:

Terrence Higgins Trust

The UK's leading HIV and sexual health charity.


UK-based charity providing accurate and trusted information about HIV and sexual health worldwide.

An HIV test is the only way to know if you have HIV

Why take an HIV test?

Current treatment for HIV


Antiretroviral drugs cannot cure HIV but work by reducing the amount of HIV in the body so the immune system can work normally.

This doesn’t get rid of HIV completely, but with the right treatment and care, someone with HIV can expect to live a long and healthy life.

It is now recommended that everyone diagnosed with HIV starts treatment straight away.

Early diagnosis enables better treatment outcomes and reduces the risk of onward transmission.

People diagnosed late have a much higher risk of developing complex health conditions including HIV -associated brain impairment.

If you test positive


If you're diagnosed with HIV, you'll have regular blood tests to monitor the progress of the HIV infection before starting treatment.

2 important blood tests are:

  1. HIV viral load test – a blood test that monitors the amount of HIV virus in your blood

  2. CD4 lymphocyte cell count – which measures how the HIV has affected your immune system

Treatment can be started at any point following your diagnosis, depending on your circumstances and in consultation with your HIV doctor.

If you test positive
Drug image by Tomasz Ryś

Antiretroviral drugs

Did you know that having an undetectable viral load when you are taking HIV treatment (ART) also stops HIV transmission? For at least 20 years, we have known that ART reduces HIV transmission. But for the last few years, leading scientists agree that the risk is not just reduced – it is stopped completely.

Image by Tomasz Ryś

HIV is treated with antiretroviral medications, which work by stopping the virus replicating in the body. This allows the immune system to repair itself and prevent further damage.

A combination of HIV drugs is used because HIV can quickly adapt and become resistant.

Some HIV treatments have been combined into a single pill, known as a fixed dose combination, although these often cost more to prescribe.

Usually, people who have just been diagnosed with HIV take between 1 and 4 pills a day.

Different combinations of HIV medicines work for different people, so the medicine you take will be individual to you.

The amount of HIV virus in your blood (viral load) is measured to see how well treatment is working. Once it can no longer be measured it's known as undetectable. Most people taking daily HIV treatment reach an undetectable viral load within 6 months of starting treatment.

Many of the medicines used to treat HIV can interact with other medicines prescribed by your GP or bought over-the-counter.

These include some nasal sprays and inhalers, herbal remedies like St John's wort, as well as some recreational drugs. Always check with your HIV clinic staff or your GP before taking any other medicines.

PrEP and PEP

What is PrEP?


Pre-exposure prophylaxis (PrEP) is an HIV prevention strategy that uses antiretroviral drugs to protect people who do not have HIV but who are at high risk of contracting HIV.

To be effective, Prep must be taken regularly, as directed. It does not prevent other sexually transmitted infections.

What is PEP?


Post-exposure Prophylaxis (PEP) is a short-term treatment that stops HIV spreading through the  body.

It must be taken within 72 hours of possible exposure to HIV.

Antiretroviral drugs
What is PREP and PEP

HIV-Associated Brain Impairment

Mildmay specialises in the treatment of HIV-Associated Neurocognitive Disorder, or HAND, impairment caused by HIV entering and affecting the brain.

This is a form of severe dementia that Mildmay is able to curtail or even reverse in the majority of our patients, enabling them to return to some form of independent living.

People with HAND often display symptoms that are very similar to dementia, such as memory loss, confusion, loss of a sense of self, difficulty in walking, speaking or carrying out everyday tasks.

Mildmay’s specialised treatment, care and rehabilitation include highly skilled medical and nursing care, treatment, rehabilitation and a combined range of therapies.

Engraved image of a human brain

More about HAND

HIV-associated neurocognitive disorders are neurological disorders associated with HIV infection and AIDS. It is a syndrome of progressive deterioration of memory, cognition, behaviour, and motor function in HIV-infected individuals during the late stages of the disease, when immunodeficiency is severe.

HAND may include neurological disorders of various severity. HIV-associated neurocognitive disorders are associated with a metabolic encephalopathy induced by HIV infection and fuelled by immune activation of macrophages and microglia. These cells are actively infected with HIV and secrete neurotoxins of both host and viral origin.

The essential features of AIDS dementia complex (ADC) are disabling cognitive impairment accompanied by motor dysfunction, speech problems and behavioural change.

Cognitive impairment is characterised by mental slowness, trouble with memory and poor concentration. Motor symptoms include a loss of fine motor control leading to clumsiness, poor balance and tremors.

Behavioural changes may include apathy, lethargy and diminished emotional responses and spontaneity.

Statistics on (late) HIV diagnosis in the UK

The most recent estimate suggests there were 105,200 people living with HIV in the UK in 2019. Of these, around 6,600 people are undiagnosed and so do not know they are HIV positive.

London continues to have the highest rates of HIV in the country: 36% of new diagnoses in 2019 were in London residents and 38% of people seen for HIV care were living in London.

Anyone can get HIV but people from some groups or parts of the world are more likely to be affected. In particular, men who have sex with men and black African people are disproportionately affected.

  • Of the 4,139 people diagnosed with HIV in the UK in 2019, 41% were gay or bisexual men.

  • Of the 1,559 heterosexual people diagnosed with HIV in 2019, 37% were black African men and women.

  • In 2017, the overall mortality rate for people aged 15-59 who were diagnosed early was, for the first time, equal to that of the general population for the same age group.

  • New diagnoses have been declining since their peak in 2005.

  • In 2019 there was a 10% drop in new diagnoses from 2018 and a 34% drop compared to 2014.

  • Of those diagnosed with HIV in 2019, 42% were diagnosed late. Of those diagnosed with HIV, 52% of heterosexual men were diagnosed late; 59% of people aged 65 and older; and only 35% of gay and bisexual men were diagnosed late.

  • As a result of combination prevention among gay and bisexual men, 2019 saw a fall of 18% in HIV diagnoses in that demographic in one year and 47% compared to 2014 – especially in London, where new diagnoses decreased by 54% in these five years.

  • Diagnoses in women however only declined by 4% in the past year. Women account for 28% of new diagnoses in 2019.

We are grateful to the Terrence Higgins Trust for these data.

Statistics on late diagnosis of HIV in the UK
Stigma and HIV

HIV is a medical condition that carries a lot of stigma, usually because people lack information about it or they make moral judgements about how someone has contracted HIV. This is because HIV is mainly transmitted through sex and can be linked to activities such as injecting drugs.

Stigma is often borne out of fear and can take many forms, including: 

  • hostility

  • physical or verbal abuse

  • someone being avoided or excluded from activities they used to take part in.

People can experience stigma in any area of their life – within their relationships, family, work, or places where they socialise, such as church. 

HIV stigma and discrimination affect the emotional well-being and mental health of people living with HIV. People living with HIV often internalise the stigma they experience and begin to develop a negative self-image. They may fear being discriminated against or judged negatively if their HIV status is revealed.

If you are experiencing stigma

This is a link to the Terrence Higgins Trust website page on stigma

More info
Nutrition and HIV

Having a balanced diet is particularly important for people living with HIV, especially if you are taking antiretroviral medications as some drugs can cause changes to the way your body metabolises some fats and sugars.

Healthy eating improves short-term health, helps you maintain a healthy weight and can help reduce the risk of developing conditions such as heart disease, diabetes, lipodystrophy and osteoporosis.

For more information on nutrition and HIV and accessing services that can support you, go to the Food Chain website. The Food Chain offers a range of nutrition services tailored to provide appropriate support to anyone living with HIV in London.

HIV pregnancy and birth

In the UK with the right treatment and care, 99% of women living with HIV give birth to healthy babies without passing on HIV.

What does COVID-19 mean for people living with HIV?:
For more information:
Find out how Mildmay helps:
Covid and HIV
how mildmay helps
bottom of page