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Health condition · Clinically reviewed

HIV and AIDS, testing, Test and Treat, and the modern ART story.

A treatable, long-term condition. One tablet a day for most - a normal life expectancy - and U=U meaning HIV cannot be passed on when treatment works.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against BHIVA, UKHSA, IAS-USA and WHO sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance including integrase inhibitors, long-acting injectables and U=U messaging.

Key facts

HIV at a glance.

The essentials, in plain English - what HIV is, how it is treated, and why testing and U=U matter.

  • What it is

    A chronic retroviral infection that depletes CD4+ T cells - HIV-1 accounts for the global epidemic, HIV-2 is largely West African.

  • UK prevalence

    Around 100,000 people live with HIV in the UK, according to UKHSA and BHIVA surveillance data.

  • U=U

    Undetectable equals untransmittable - people on effective treatment cannot pass HIV on sexually.

  • Test and Treat

    Antiretroviral therapy is started at diagnosis regardless of CD4 count - lifelong, once daily for most.

  • First-line therapy

    Integrase inhibitor plus two NRTIs - typically bictegravir or dolutegravir based, single-tablet regimens.

  • Long-acting options

    Injectable cabotegravir with rilpivirine every one to two months, and twice-yearly lenacapavir for resistant disease.

Why this guide matters

A treatable long-term condition.

HIV is diagnosed with a simple blood test, treated with one tablet a day for most people, and cannot be passed on when treatment works. The three points below shape everything else on this page.

  • Testing is easy and offered widely

    Fourth-generation blood tests, point-of-care and home self-tests are all accurate. UKHSA supports opt-out testing in many NHS settings.

  • Test and Treat is the standard

    ART is started at diagnosis regardless of CD4 count. Rapid initiation protects the immune system and prevents onward transmission.

  • Prevention has never been better

    PrEP, PEP, treatment-as-prevention and vaccination together make new UK infections increasingly avoidable.

How the diagnosis is made

From first test to a clear plan.

The steps a UK GP, sexual health service or HIV clinic will normally follow, in order - so you know what to expect and why.

  1. 01

    Screening

    Fourth-generation combo test

    Serum antibody and p24 antigen assay - the UK standard, detecting infection from around two to four weeks.

  2. 02

    Screening

    Point-of-care or self-testing

    Rapid finger-prick tests in sexual health, primary care and at home - reactive results always need confirmation.

  3. 03

    Screening

    Universal opt-out screening

    Sexual health, antenatal, emergency department and primary care opt-out testing in high-prevalence areas per UKHSA.

  4. 04

    Confirming

    Confirmatory testing

    Repeat immunoassay with HIV-1/2 differentiation, Western blot or HIV RNA PCR - performed at a specialist commissioned HIV clinic.

  5. 05

    Confirming

    Baseline HIV workup

    Viral load, CD4 count, resistance genotype and HLA-B*5701 - defines starting treatment and prognosis.

  6. 06

    Planning

    Co-infection screening

    Hepatitis B, hepatitis C, syphilis, other STIs and latent TB - identified and treated alongside HIV.

  7. 07

    Planning

    Specialist MDT referral

    All new diagnoses are managed within a specialist commissioned HIV clinic, with rapid ART initiation.

Typical timeline: from a first test to starting therapy in days, not weeks.

Symptoms

What HIV can look like.

From a brief seroconversion illness, through years of clinical silence, to advanced immunosuppression - and why testing matters more than symptoms.

  • Seroconversion illness

    Two to four weeks after infection - fever, sore throat, lymphadenopathy, rash and myalgia. A specialist assessment window.

  • Asymptomatic latency

    Years of clinical silence with ongoing viral replication - the reason testing matters more than symptoms.

  • Constitutional symptoms

    Weight loss, night sweats, chronic diarrhoea and persistent fever suggest advancing untreated disease.

  • Generalised lymphadenopathy

    Persistent nodes at two or more extra-inguinal sites - a classic mid-stage feature.

  • Opportunistic infections

    Pneumocystis pneumonia (see chest infections), oesophageal candida, cryptococcal disease, toxoplasmosis and CMV.

  • AIDS-defining illness

    CD4 count below 200 or an AIDS-defining diagnosis such as PJP, Kaposi sarcoma or CNS lymphoma.

  • HIV-associated neurocognitive disorder

    Ranges from mild cognitive slowing to HIV-associated dementia in advanced untreated disease.

  • Red flag - advanced presentation

    New diagnosis with CD4 below 200, weight loss, oral thrush or unexplained fever needs same-day specialist input.

Treatment

How HIV is treated in the UK.

Lifelong antiretroviral therapy, started at diagnosis - integrase inhibitor based, single-tablet for most, with long-acting injectable options for those who suit them.

  • Integrase inhibitor backbone

    Bictegravir, dolutegravir or raltegravir - first-line for almost all UK adults, per BHIVA and IAS-USA.

  • NRTI pairing

    Tenofovir (TAF or TDF) with emtricitabine or lamivudine - the standard companion to the integrase inhibitor.

  • Single-tablet regimens

    Bictegravir/emtricitabine/tenofovir (Biktarvy) and dolutegravir/lamivudine (Dovato) - once-daily, well tolerated.

  • Long-acting injectable ART

    Cabotegravir plus rilpivirine (Cabenuva) every one to two months - see our long-acting ARV clinic.

  • Lenacapavir

    Twice-yearly subcutaneous option (Sunlenca) for multi-drug resistant HIV - specialist commissioned only.

  • Pre-exposure prophylaxis (PrEP)

    Daily or event-based tenofovir/emtricitabine, plus emerging long-acting options - see our PrEP clinic.

  • Post-exposure prophylaxis (PEP)

    A 28-day course started within 72 hours of exposure - see our PEP clinic and attend A&E or GUM without delay.

  • OI prophylaxis and vaccinations

    Co-trimoxazole, azithromycin and isoniazid where indicated - plus HPV, hepatitis, pneumococcal, influenza and COVID vaccination.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and international specialist standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your HIV clinician knows your history and can tell you which parts apply to you. If in doubt, contact your specialist team.

  • BHIVA. Guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy.

  • UKHSA. HIV surveillance, testing and prevention reports.

  • IAS-USA. Antiretroviral drugs for treatment and prevention of HIV in adults.

  • WHO. Consolidated guidelines on HIV prevention, testing, treatment and care.

Red flags

When HIV needs urgent attention.

Most HIV care is planned and outpatient. These are the situations where same-day specialist assessment or emergency care is needed.

  • Suspected seroconversion

    Flu-like illness with lymphadenopathy and rash after possible exposure - test urgently, including HIV RNA PCR if within the window.

  • CD4 below 200

    High risk of opportunistic infection - needs same-day specialist commissioned HIV review and prophylaxis.

  • Pneumocystis pneumonia

    Dry cough, exertional breathlessness and desaturation - see our chest infection guide and seek urgent hospital assessment.

  • Cryptococcal meningitis

    Headache, fever and confusion in advanced HIV - see our cryptococcosis guide. A neurological emergency.

  • Toxoplasmosis or CNS lymphoma

    Focal neurology, seizures or altered cognition - urgent imaging and specialist review.

  • Kaposi sarcoma or lymphoma

    Purple skin or mucosal lesions, or systemic B symptoms - see our Kaposi sarcoma guide and refer urgently.

  • Pregnancy in an untreated woman

    Immediate specialist HIV and antenatal referral - vertical transmission is nearly always preventable with ART.

  • Recent high-risk exposure

    Consider PEP within 72 hours and PrEP for ongoing risk - see our PEP and PrEP clinic pages.

  • Notifiable surveillance

    HIV is under UKHSA surveillance - anonymised reporting supports the national response.

Living with it

A long-term condition, not a life sentence.

Four things that make the biggest difference year on year - staying on treatment, understanding U=U, keeping your clinic appointments and reaching for peer support when you want it.

A quiet reminder

Consistency is what turns HIV into a routine.

Steady daily doses and regular reviews do far more than any single conversation about the diagnosis.

  1. 01 Adherence

    One tablet, most days for life

    Modern ART is once daily and well tolerated - consistent adherence keeps viral load undetectable and health normal.

  2. 02 U=U

    Undetectable equals untransmittable

    A suppressed viral load means HIV cannot be passed on sexually - a message worth repeating to partners and family.

  3. 03 Care

    Stay in specialist follow-up

    Regular clinic visits monitor viral load, CD4, kidneys, bone health and mental health - and update the plan as you age.

  4. 04 Support

    You are not alone

    Terrence Higgins Trust, NAM and i-Base offer peer support, plain-English information and legal advice.

Frequently asked

Everything we get asked about HIV.

Quick answers on testing, U=U, Test and Treat, PrEP, PEP and long-acting therapy.

  • What is HIV?

    Human immunodeficiency virus is a retrovirus that infects CD4+ T cells - the coordinators of the immune system. Untreated, it causes gradual immune decline over years and can progress to AIDS. With modern antiretroviral therapy started at diagnosis, life expectancy is close to normal.

  • What does U=U mean?

    Undetectable equals untransmittable. When someone with HIV takes effective antiretroviral therapy and their viral load stays suppressed below the level of detection for at least six months, they cannot pass HIV on to sexual partners. It is one of the most important public health messages of the last decade.

  • When should I start treatment?

    At diagnosis, regardless of CD4 count. Current BHIVA, IAS-USA and WHO guidance recommends Test and Treat - offering same-day or rapid antiretroviral therapy to all people diagnosed with HIV. Starting early protects the immune system and prevents onward transmission.

  • What treatments are available?

    For most adults, first-line therapy is an integrase inhibitor such as bictegravir or dolutegravir combined with two NRTIs (tenofovir plus emtricitabine or lamivudine) in a single daily tablet. Long-acting cabotegravir with rilpivirine injections, and twice-yearly lenacapavir for resistant HIV, are increasingly used within specialist commissioned services.

  • What is PrEP and who should consider it?

    Pre-exposure prophylaxis is a preventive treatment for people who are HIV negative and at ongoing risk of exposure. Daily or event-based tenofovir/emtricitabine is highly effective, and long-acting injectable options are now approved. Our PrEP clinic can assess suitability and provide monitoring.

  • What should I do after a possible exposure?

    Attend an emergency department or sexual health clinic within 72 hours to be assessed for post-exposure prophylaxis (PEP) - a 28-day course of antiretrovirals that substantially reduces the chance of infection. See our PEP clinic page. Testing and follow-up are arranged from that first visit.

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