Quick answer

What is hiv?

HIV is a virus that attacks the immune system — without treatment it progresses to AIDS. Modern antiretroviral therapy (ART) suppresses the virus to undetectable levels, allowing normal life expectancy and preventing sexual transmission (U=U). Free confidential testing at sexual health clinics — including rapid tests. Post-exposure prophylaxis (PEP) within 72 hours after risk may prevent infection. PrEP prevents HIV in people at ongoing risk.

HIV — facts in the treatment era

Human immunodeficiency virus (HIV) attacks CD4 immune cells. Without treatment, immune failure leads to AIDS — life-threatening opportunistic infections and cancers.

Modern antiretroviral therapy (ART) transformed HIV from fatal to chronic manageable condition — normal life expectancy with early diagnosis and adherence.

Transmission

HIV is present in:

  • blood
  • semen and pre-ejaculate
  • vaginal fluids
  • rectal fluids
  • breast milk

Routes:

  • condomless sex — anal and vaginal highest risk
  • sharing needles — injecting drug use
  • mother to child — pregnancy, birth, breastfeeding — preventable with treatment
  • occupational needle stick — healthcare workers — PEP

Not transmitted by:

  • saliva, sweat, tears (unless visibly blood-stained)
  • kissing, hugging
  • sharing cups, towels, toilets
  • insect bites

Stages

Acute HIV (seroconversion)

2 to 4 weeks post-exposure:

  • flu-like illness
  • fever, sore throat
  • rash
  • swollen glands
  • mouth ulcers

Often missed — resembles glandular fever or flu.

Clinical latency

Years — no symptoms — virus replicates — CD4 count falls slowly.

AIDS (untreated advanced HIV)

CD4 <200 or AIDS-defining illness:

  • PCP pneumonia
  • Kaposi sarcoma
  • severe candidiasis
  • wasting, dementia

Rare in UK with testing and treatment access.

Testing

Free confidential:

  • sexual health clinics
  • GP
  • home sampling kits
  • rapid point-of-care tests

4th generation lab test — detects antibody and p24 antigen — 4 weeks post-exposure sensitivity high.

Window period: repeat 12 weeks if negative after single high-risk exposure.

Routine offer alongside STI screen — syphilis, chlamydia, gonorrhoea.

Treatment — ART

Start soon after diagnosis — protects immune system, prevents transmission.

Usually one tablet daily combining 3 drugs — fixed-dose combinations.

Goals:

  • viral load undetectable (<200 copies/ml)
  • CD4 recovery
  • normal lifespan

Monitoring: viral load, CD4, kidney function, lipids, hepatitis co-infection screen.

U=U — Undetectable = Untransmittable

When sustained undetectable viral load on ART:

  • zero sexual transmissions in PARTNER and Opposites Attract studies
  • ethical duty to treat for personal and public health

Does not prevent other STIs — condoms still advised for STI prevention.

PEP — emergency after exposure

Post-exposure prophylaxis:

  • within 72 hours — sooner better — ideally <24h
  • 28 days HIV medicines
  • sexual health clinic or A&E

After condom break, sexual assault, needle stick.

PrEP — prevention before exposure

Pre-exposure prophylaxis — tenofovir/emtricitabine:

  • daily or event-based dosing (MSM protocols)
  • NHS England commissioned for eligible high-risk groups
  • reduces HIV acquisition ~86% daily, ~86% on-demand in trials when adherent

Sexual health clinic assesses eligibility.

Living with HIV

  • employment — equality law protection
  • disclosure — personal choice except insurance/dental surgery specific questions
  • pregnancy — vertical transmission <1% with treatment and obstetric plan
  • mental health support — diagnosis distress normal — counselling available

Terrence Higgins Trust — advocacy, helpline.

HIV and other conditions

Higher rates of:

  • cardiovascular disease — manage risk factors
  • some cancers — screening programmes
  • bone density loss — monitor

Interactions — ART with many medicines — always tell prescribers.

HIV in 2026 is testable, treatable, preventable — stigma outdated; late diagnosis remains main UK problem — test if at risk.

Common questions

How is HIV transmitted?
Unprotected vaginal or anal sex, sharing needles or drug equipment, mother to baby in pregnancy or breastfeeding without treatment, and very rarely through oral sex or blood transfusion (UK blood supply screened). Not transmitted by kissing, hugging, sharing cups, toilet seats, or insect bites.
What are the symptoms of HIV?
Acute seroconversion — fever, sore throat, rash, swollen glands, fatigue — 2 to 4 weeks after infection, lasts days to weeks. Then clinical latency — often no symptoms for years. Untreated — progressive immune damage — opportunistic infections, weight loss, cancers — AIDS. Testing detects before symptoms.
What does undetectable equals untransmittable mean?
When HIV treatment suppresses virus to undetectable levels in blood (sustained), sexual transmission to partners does not occur — U=U — supported by major studies. Requires good adherence and regular monitoring. Condoms still protect against other STIs.
How often should I test for HIV?
At least annually if sexually active with changing partners; every 3 months if higher risk (MSM without PrEP, injecting drug use). Test 4 weeks after exposure for 4th generation lab test — repeat at 12 weeks to exclude rare late seroconversion if initial negative after risk.
What is PEP and PrEP?
PEP (post-exposure prophylaxis) — 28 days HIV medicines started within 72 hours after condomless sex or needle stick — emergency prevention. PrEP — daily (or on-demand) tablets before exposure — NHS for eligible high-risk individuals — reduces acquisition by ~86 to 99% when taken correctly.
Is there a cure for HIV?
No widely available cure — lifelong ART controls infection. A few cases of sustained remission reported in research contexts. Vaccine development ongoing. With treatment, life expectancy near normal.

Sources