Overview
HIV (Human Immunodeficiency Virus) attacks and weakens the immune system by destroying CD4 cells (T-helper lymphocytes). Without treatment, the immune system is gradually destroyed, leading to AIDS (Acquired Immunodeficiency Syndrome), where the body cannot fight infections or cancers. With modern antiretroviral therapy, HIV is a manageable chronic condition and life expectancy is near-normal.
How common is it?
About 105,000 people are living with HIV in the UK. Globally, around 39 million people are living with the virus. An estimated 1 in 12 people with HIV in the UK does not know they have it.
Causes and risk factors
HIV is transmitted through specific body fluids: blood, semen, vaginal fluids, rectal fluids, and breast milk. It is not spread through everyday contact such as hugging, sharing food, or insect bites.
Common risk factors
- Unprotected anal or vaginal sex with an infected person
- Sharing injecting drug equipment
- Mother to child transmission during birth or breastfeeding
- Blood transfusion with infected blood (rare in UK with screening)
- Needlestick injury with contaminated blood (healthcare workers)
Symptoms
- Many people have no symptoms for years after initial infection
- Acute HIV infection (2 to 4 weeks after exposure): flu-like illness with fever, rash, sore throat, swollen lymph nodes
- Without treatment: weight loss, night sweats, recurrent infections, thrush
- AIDS-defining illnesses: Pneumocystis pneumonia, toxoplasmosis, CMV retinitis, Kaposi sarcoma
When to see a doctor
Test for HIV if you have had unprotected sex, share drug equipment, or have any of the above symptoms. HIV testing is available at sexual health clinics, GP surgeries, and online (self-test kits). Test as early as possible.
Diagnosis
Blood test detects HIV antibodies and p24 antigen. The 4th generation combined test can detect infection from about 4 weeks after exposure. Viral load and CD4 count are used to monitor treatment response.
Treatments
Antiretroviral therapy (ART)
Daily oral tablets combining 2 to 3 different antiretroviral drugs suppress viral replication to undetectable levels. People with undetectable viral load cannot transmit HIV to sexual partners (U=U: Undetectable = Untransmittable).
PrEP (Pre-Exposure Prophylaxis)
Daily tenofovir/emtricitabine (or event-based dosing) taken by HIV-negative people at high risk. Reduces HIV acquisition risk by over 99% when taken consistently.
PEP (Post-Exposure Prophylaxis)
Emergency antiretroviral treatment started within 72 hours of potential HIV exposure and taken for 28 days. Available at sexual health clinics and A&E.
Self-care and lifestyle
- Adhere strictly to ART medication as missing doses allows viral rebound
- Regular sexual health screenings and STI treatment reduce complications
- Inform sexual partners of your HIV status and use condoms to prevent other STIs
- Live a healthy lifestyle: exercise, healthy diet, and avoid smoking which worsens immunosuppression
Prevention
Condom use during sex, PrEP for high-risk individuals, clean needle programmes, HIV testing, and treatment (treatment as prevention) are all evidence-based prevention strategies.