HIV & PrEP
Symptoms, Causes & Treatment
Everything you need to know about HIV and PrEP: how HIV is transmitted, how it is treated, and how PrEP and PEP prevent new infections.
What Is HIV?
Human immunodeficiency virus (HIV) is a virus that attacks the immune system, specifically the CD4+ T cells (also known as T-helper cells) that are essential for fighting infections. Without treatment, HIV progressively weakens the immune system over years, eventually leading to acquired immunodeficiency syndrome (AIDS) -- a stage at which the body can no longer defend against opportunistic infections and certain cancers.
With modern antiretroviral therapy (ART), people living with HIV can expect a near-normal life expectancy and quality of life. When treatment successfully suppresses the viral load to undetectable levels, HIV cannot be transmitted sexually. This principle is known as Undetectable = Untransmittable (U=U) and is supported by robust scientific evidence endorsed by major public health bodies worldwide.
In the UK, an estimated 106,000 people are living with HIV, of whom approximately 5,000 are undiagnosed. Early diagnosis and prompt treatment are critical -- both for the health of the individual and for preventing onward transmission.
HIV is not a death sentence. It is a manageable, chronic condition. Stigma and misinformation remain significant barriers to testing and treatment, and tackling these is essential to ending new HIV transmissions.
What Are the Symptoms of HIV?
HIV symptoms depend on the stage of infection. Early recognition of seroconversion illness enables earlier diagnosis and treatment.
Primary HIV infection (seroconversion): flu-like illness 2–4 weeks after exposure — fever, sore throat, rash, swollen glands · Chronic HIV: fatigue, weight loss, recurrent infections, night sweats · AIDS-defining conditions: PCP pneumonia, CMV retinitis, toxoplasmosis, Kaposi's sarcoma
Any new HIV diagnosis requires same-day specialist referral · Possible HIV exposure within 72 hours — PEP must be started immediately · Signs of AIDS-related illness (severe weight loss, persistent cough, visual disturbance) · Fever in a known HIV-positive person not on ART
If you have had a possible HIV exposure within the last 72 hours, attend A&E or a sexual health clinic immediately to access PEP. Do not wait for symptoms — PEP only works if started promptly. Every hour matters.
What Causes HIV & How Is It Transmitted?
HIV is caused by the Human Immunodeficiency Virus, which is transmitted through specific body fluids. Understanding transmission routes is essential for prevention and reducing stigma.
HIV (Human Immunodeficiency Virus) infects and destroys CD4+ T-helper lymphocytes. Progressive CD4 depletion impairs cellular immunity, causing susceptibility to opportunistic infections and AIDS-defining cancers.
HIV is transmitted through blood, semen, vaginal fluids, rectal secretions, and breast milk. Routes include unprotected sex, sharing needles, blood-to-blood contact, and mother-to-child transmission.
Without treatment, HIV progresses through primary infection, clinical latency (can last 10+ years), and AIDS. ART suppresses viral load to undetectable levels, preventing progression and transmission (U=U).
STIs are transmitted through unprotected vaginal, anal, or oral sex. Some (herpes, HPV, syphilis) can spread through skin-to-skin contact even without penetration or visible symptoms.
Many STIs, particularly chlamydia, gonorrhoea, and early HIV, cause no symptoms at all. Regular testing is the only way to detect them — waiting for symptoms means delayed treatment and onward transmission.
Condoms reduce STI transmission by 85–98% when used consistently and correctly. They are less effective for infections spread by skin contact (herpes, HPV, syphilis) where lesions extend beyond the condom-covered area.
Key Risk Factors
How Is HIV Diagnosed & Monitored?
The 4th generation HIV antigen/antibody combination test can detect HIV from 10–28 days after exposure. A negative result at 28 days is highly reassuring; a final test at 45–90 days is recommended after significant exposures. HIV testing is free, confidential, and available from sexual health clinics, GPs, and online.
How Is HIV Treated?
All HIV-positive individuals should start ART regardless of CD4 count. Modern regimens are simple, well-tolerated, and highly effective at achieving viral suppression.
Supportive Measures
ART requires consistent daily adherence to maintain viral suppression. Missing doses risks rebound viraemia and resistance. Most people on modern single-tablet regimens achieve complete viral suppression within 3–6 months and maintain it indefinitely with adherence.
Living Long-Term with HIV
HIV requires lifelong treatment but produces no symptoms when well-controlled. Annual monitoring includes CD4, viral load, kidney function, liver function, lipid profile, and bone density. HIV-positive people on suppressive ART have the same life expectancy as the HIV-negative population and cannot transmit HIV to sexual partners.
When Should You Seek Help for HIV?
Possible HIV exposure within 72 hours — attend A&E or sexual health clinic immediately for PEP · Signs of AIDS-defining illness (severe breathlessness, vision loss, confusion) · Fever in a newly diagnosed HIV-positive person not on treatment.
You have had unprotected sex and want an HIV test · You want to start PrEP · You have a new HIV diagnosis and need referral · You are HIV-positive and your viral load is detectable · You are pregnant and HIV-positive.
How to Prevent HIV
HIV is preventable. Multiple highly effective tools are now available that, used consistently, can stop HIV transmission entirely.
PrEP (Truvada or Descovy) is available free on the NHS at sexual health clinics for eligible high-risk individuals. It is over 99% effective when taken as prescribed. Regular HIV and kidney function testing is required during use.
If you are HIV-positive and on effective ART with an undetectable viral load, you cannot transmit HIV to sexual partners (U=U — Undetectable = Untransmittable). This is one of the most important advances in HIV medicine.
Annual STI testing is recommended for all sexually active people. Those with multiple partners should test every 3 months. Free NHS testing is available at sexual health clinics, online via SHGM/SH:24, and from GP surgeries.
Use condoms consistently for vaginal, anal, and oral sex with new or casual partners. Dental dams reduce transmission during oral-vulval contact. Lube reduces condom breakage and anal mucosal trauma.
Notify all recent sexual partners when diagnosed with an STI so they can be tested and treated. Partner notification can be done directly or anonymously through the sexual health clinic (contact tracing service).
HPV vaccination prevents 90% of cervical cancer and most genital warts. Hepatitis B vaccine is recommended for all MSM, PWID, and sexual health clinic attendees not previously vaccinated.
Speak to a Clinician About HIV Testing and PrEP
Through The GP Service, a licensed clinician can provide HIV risk assessment, arrange HIV testing, prescribe PrEP for eligible individuals, and refer to an NHS HIV clinic for ART.



Expert clinical advice, when you need it.
HIV & PrEP FAQs
Yes. HIV is now a manageable chronic condition, not a death sentence. With antiretroviral therapy (ART), people with HIV can live long, healthy lives with a normal life expectancy. ART suppresses the virus to undetectable levels in the blood, meaning it cannot be transmitted sexually (Undetectable = Untransmittable, or U=U). Most people on modern ART take a single tablet daily and experience minimal side effects. HIV does not prevent you from having children, working, or having a fulfilling life. In the UK, HIV care is excellent and free on the NHS. The biggest barrier to good outcomes is late diagnosis — testing early is life-saving.
PEP (post-exposure prophylaxis) is a 28-day course of antiretroviral drugs that prevents HIV infection after a potential exposure. It must be started within 72 hours — the sooner the better. PEP is available from A&E departments, sexual health clinics, and some GUM clinics 24/7. It is free on the NHS for NHS patients. PEP is not a substitute for PrEP or condoms and should be used only in genuine emergencies (unprotected sex with a known HIV-positive person not on suppressive ART, condom failure, sexual assault, or needlestick). After completing PEP, an HIV test at 45 days and 3 months confirms whether infection was prevented.
STI testing is recommended annually for all sexually active people. Those with new or multiple partners should test every 3 months. Testing is free at NHS sexual health clinics and from online services (SH:24, SHGM). You do not need symptoms to be tested — most STIs cause no symptoms. A full STI screen covers chlamydia, gonorrhoea, syphilis, HIV, hepatitis B, and hepatitis C. Specific sites tested (urine, swabs, blood) depend on your sexual practices. Results are usually available within 1–2 weeks. Positive results trigger automatic partner notification advice.
Not all STIs are curable, but all are treatable. Bacterial STIs — chlamydia, gonorrhoea, and syphilis — are fully curable with antibiotics when diagnosed promptly. Viral STIs — HIV, herpes, HPV, and hepatitis B — cannot be cured but can be effectively managed. HIV is controlled with ART to the point of undetectability. Herpes is managed with antivirals that suppress outbreaks. HPV often clears naturally within 1–2 years in people with healthy immune systems. Genital warts can be treated and removed, though the underlying HPV virus may persist. The key message: all STIs are manageable with prompt diagnosis and treatment.
Without treatment, chlamydia can persist silently for months or years, causing progressive damage to the reproductive tract. In women, untreated chlamydia causes pelvic inflammatory disease (PID) in 10–15% of cases, leading to tubal factor infertility, chronic pelvic pain, and ectopic pregnancy risk increased 6–10-fold. In men, chlamydia causes epididymo-orchitis, which can impair sperm production and quality. Reactive arthritis (formerly Reiter's syndrome) — involving joint inflammation, eye inflammation, and urethritis — is a rare but recognised complication. These complications are entirely preventable with prompt diagnosis and a simple 7-day course of doxycycline.
Gonorrhoea is increasingly difficult to treat due to rising antibiotic resistance. The current UK first-line treatment is a single intramuscular injection of ceftriaxone 1g. A test of cure is required 2 weeks later to confirm eradication. Azithromycin is no longer recommended routinely due to resistance. Multidrug-resistant gonorrhoea has been identified in multiple countries, including the UK. If you have been treated for gonorrhoea and symptoms persist, return to the clinic immediately — do not take additional antibiotics without guidance. Treatment of all recent sexual partners is essential to prevent reinfection.
Syphilis in pregnancy can cause miscarriage, stillbirth, premature birth, and severe congenital syphilis in the newborn (causing bone, liver, brain, and skin disease). All pregnant women in the UK are offered a syphilis blood test at their first antenatal appointment. Treatment with benzathine penicillin G during pregnancy is safe and highly effective at preventing mother-to-child transmission. If you are pregnant and believe you may have been exposed to syphilis, seek urgent testing and treatment. Contact tracing of all recent partners is mandatory. Untreated syphilis in pregnancy is one of the most preventable causes of neonatal death.
PE affects approximately 20–30% of men at some point — making it the most common male sexual dysfunction. Many men suffer in silence due to embarrassment, assuming it is shameful or untreatable. In reality, PE is a well-recognised medical condition with highly effective treatments. Dapoxetine (a short-acting SSRI licensed specifically for PE) can more than triple ejaculatory latency time in clinical trials. Behavioural techniques (stop-start, squeeze) are effective for lifelong PE. Combining medication with psychological or couples therapy produces the best outcomes. Most men with PE who seek treatment experience significant improvement.
