Overview
Human Immunodeficiency Virus (HIV) is a retrovirus that attacks the body’s immune system, specifically CD4‑positive T‑lymphocytes, leading to progressive immune deficiency. If untreated, HIV infection can evolve into AIDS (Acquired Immunodeficiency Syndrome), the most advanced stage of the disease.
- Who it affects: Anyone can be infected, regardless of age, gender, ethnicity, or sexual orientation. Certain groups—such as men who have sex with men (MSM), people who inject drugs, sex workers, and transgender individuals—have higher incidence rates.
- Global prevalence: According to the World Health Organization (WHO), ~38.4 million people were living with HIV worldwide in 2023, with about 1.5 million new infections that year.1
- U.S. prevalence: The CDC estimates ~1.2 million people in the United States are living with HIV, and ~13 % are unaware of their infection.2
Symptoms
HIV symptoms vary by stage. Many people experience no symptoms for years after initial infection, making routine testing essential.
Acute (Primary) HIV Infection – 2‑4 weeks after exposure
- Fever
- Headache
- Sore throat
- Swollen lymph nodes (especially neck, armpits, groin)
- Muscle & joint aches
- Rash (often on trunk)
- Night sweats
- Fatigue
- Gastrointestinal upset (nausea, vomiting, diarrhea)
- Weight loss
These symptoms mimic flu or mononucleosis and can last from a few days to several weeks.3
Clinical Latency (Chronic HIV) – Years without symptoms
- Persistent low‑grade fever
- Swollen lymph nodes
- Unexplained weight loss
- Recurrent oral or genital thrush (candidiasis)
- Night sweats
- Frequent skin infections or rashes
During this phase, the virus replicates but the immune system still functions adequately enough to prevent severe illness.
AIDS‑Defining Illnesses (CD4 count < 200 cells/mm³)
- Severe, unexplained weight loss (≥10% of body weight)
- Persistent fever > 38 °C for ≥ 1 month
- Profuse, unexplained night sweats
- Chronic diarrhoea (≥ 1 month)
- Severe opportunistic infections (e.g., Pneumocystis jirovecii pneumonia, cryptococcal meningitis, disseminated Mycobacterium avium complex)
- Cancer of the Kaposi sarcoma, non‑Hodgkin lymphoma, invasive cervical cancer
- Neurological complications (e.g., HIV‑associated dementia, progressive multifocal leukoencephalopathy)
Causes and Risk Factors
How HIV is Transmitted
- Sexual contact: Unprotected vaginal, anal, or oral sex with an infected partner. Anal intercourse carries the highest per‑act transmission risk.
- Blood exposure: Sharing needles or syringes, contaminated blood transfusions (rare in countries with screened blood supplies), accidental needle sticks.
- Mother‑to‑child (vertical) transmission: During pregnancy, childbirth, or breastfeeding.
Key Risk Factors
- Having multiple sexual partners or a partner with unknown HIV status.
- Inconsistent or no condom use.
- Use of injectable drugs without sterile equipment.
- Presence of other sexually transmitted infections (STIs) that cause genital ulcers.
- Engaging in commercial sex work.
- Being part of a high‑prevalence community (e.g., MSM, transgender women).
- Limited access to preventive services (e.g., PrEP, condoms, harm‑reduction programs).
Diagnosis
Early detection is vital for treatment success and reducing transmission.
Screening Tests
- Fourth‑generation combination immunoassay: Detects both HIV‑1/2 antibodies and p24 antigen. Provides results within days to weeks after exposure.
- Rapid antibody tests (point‑of‑care): Finger‑stick or oral fluid tests delivering results in 20‑30 minutes. Positive results require confirmatory testing.
Confirmatory Tests
- HIV‑1/HIV‑2 differentiation immunoassay – distinguishes between the two virus types.
- Nucleic acid test (NAT): Detects viral RNA; used when acute infection is suspected or when antibody tests are indeterminate.
Baseline Staging After Diagnosis
- CD4+ T‑cell count (cells/mm³)
- HIV viral load (copies/mL) – measures how actively the virus is replicating.
- Genotypic resistance testing – determines if the virus carries mutations that confer drug resistance, guiding regimen choice.
- Screening for co‑infections (HBV, HCV, TB, syphilis, hepatitis A).
Treatment Options
Current HIV therapy is called antiretroviral therapy (ART)**, which involves a combination of drugs that suppress viral replication, preserve immune function, and prevent disease progression.
First‑Line ART Regimens (2024 WHO/NIH recommendations)
- Integrase strand transfer inhibitor (INSTI)‑based regimen: e.g., Bictegravir/Emtricitabine/Tenofovir alafenamide (B/F/TAF) – one‑pill daily.
- Dolutegravir‑based regimen: Dolutegravir + Lamivudine + Tenofovir disoproxil fumarate (DTG+3TC+TDF) – also single‑tablet.
These regimens are preferred because they have high barrier to resistance, minimal side‑effects, and convenient dosing.
Second‑Line and Salvage Therapy
- Protease inhibitor (PI)‑based combos (e.g., Darunavir/ritonavir + two nucleos(t)ide reverse transcriptase inhibitors).
- Second‑generation INSTIs (e.g., Cabotegravir) for patients with INSTI resistance.
- Entry‑inhibitors (e.g., Maraviroc) for CCR5‑tropic virus when other options fail.
Adjunctive Care
- Vaccinations: Hepatitis A/B, HPV, influenza, COVID‑19, pneumococcal, and meningococcal as indicated.
- Screening and prophylaxis for opportunistic infections (e.g., TMP‑SMX for Pneumocystis pneumonia when CD4 < 200 cells/µL).
- Management of comorbidities: cardiovascular disease, renal dysfunction, bone health, mental health.
Lifestyle Recommendations
- Adherence: Take ART exactly as prescribed—missed doses can lead to viral rebound and resistance.
- Nutrition: Balanced diet rich in fruits, vegetables, lean protein; limit processed foods and excess alcohol.
- Exercise: Aim for ≥150 minutes of moderate aerobic activity per week.
- Avoid smoking and illicit drug use; seek substance‑use treatment if needed.
Living with HIV Infection
Daily Management Tips
- Medication routine: Use a pillbox, phone alarms, or app reminders.
- Regular monitoring: Lab tests every 3‑6 months (viral load, CD4 count, renal & liver function). Once viral load is suppressed for > 2 years, some labs may be spaced out.
- Stay informed: Keep up with new guidelines; discuss any side‑effects with your provider.
- Maintain a support network: Peer groups, mental‑health counseling, or online communities can reduce isolation.
- Disclose thoughtfully: In many jurisdictions, you are not legally required to tell partners once viral load is undetectable, but open communication promotes trust and safer practices.
- Sexual health: Use condoms consistently, even with an undetectable viral load, to protect against other STIs.
- Pregnancy planning: Women with HIV can have healthy pregnancies with ART and obstetric care; discuss options early.
Undetectable = Untransmittable (U=U)
When ART maintains a viral load < 200 copies/mL (often < 50 copies/mL), the risk of sexual transmission is effectively zero. This fact underscores the importance of early and consistent treatment.4
Prevention
- Pre‑exposure prophylaxis (PrEP): Daily oral Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) or Long‑acting injectable Cabotegravir reduces acquisition risk by > 90 % when taken correctly.5
- Post‑exposure prophylaxis (PEP): 28‑day ART started within 72 hours after a high‑risk exposure; consult a health professional promptly.
- Condoms: Male and female condoms are > 80 % effective at preventing HIV when used consistently.
- Harm‑reduction for people who inject drugs: Needle‑exchange programs, supervised injection sites, and opioid substitution therapy.
- Routine testing: At least once a year for sexually active adults; more frequent for high‑risk groups.
- Maternal‑child prevention: ART for pregnant women, elective cesarean delivery if viral load > 1,000 copies/mL, and avoidance of breastfeeding in settings where safe formula is available.
Complications if Untreated
Without ART, HIV progressively damages the immune system, leading to a spectrum of opportunistic infections and malignancies.
- Opportunistic infections: Pneumocystis jirovecii pneumonia, cytomegalovirus retinitis, cryptococcal meningitis, disseminated tuberculosis.
- Cancers: Kaposi sarcoma, non‑Hodgkin lymphoma, invasive cervical cancer.
- Neurological disorders: HIV‑associated neurocognitive disorder (HAND), peripheral neuropathy, vacuolar myelopathy.
- Cardiovascular disease: Accelerated atherosclerosis, myocardial infarction.
- Renal disease: HIV‑associated nephropathy (HIVAN) and drug‑related nephrotoxicity.
- Liver disease: Co‑infection with hepatitis B or C leads to cirrhosis, hepatocellular carcinoma.
- Bone disease: Osteopenia/osteoporosis due to chronic inflammation and some ART agents.
When to Seek Emergency Care
Call 911 or go to the nearest emergency department if you experience any of the following:
- Severe shortness of breath or chest pain.
- Sudden high fever (≥ 39 °C) with chills.
- Neurological emergencies: sudden severe headache, vision loss, confusion, seizures, or difficulty speaking.
- Profuse, unexplained bleeding (e.g., gastrointestinal bleed, severe oral ulceration).
- Acute abdominal pain with vomiting, especially if accompanied by a high fever.
- Sudden swelling of the legs or rapid weight gain (possible heart failure).
- Signs of an allergic reaction to medication: hives, swelling of the face or throat, difficulty breathing.
These symptoms may signal life‑threatening opportunistic infections or drug reactions and require immediate medical attention.6
References
- World Health Organization. Global HIV & AIDS statistics — 2023 update. WHO; 2023. https://www.who.int/news-room/fact-sheets/detail/hiv-aids
- Centers for Disease Control and Prevention. HIV Surveillance Report, 2023. CDC; 2024. https://www.cdc.gov/hiv/library/reports/hiv-surveillance.html
- Mayo Clinic. HIV symptoms: Acute infection, AIDS, and more. Mayo Clinic; 2023. https://www.mayoclinic.org/diseases-conditions/hiv-aids/symptoms-causes/syc-20373524
- U.S. Department of Health & Human Services. Undetectable = Untransmittable (U=U) Fact Sheet. 2022. https://www.hhs.gov/opa/2022/08/01/undetectable-untransmittable-ufact-sheet.html
- CDC. Pre-Exposure Prophylaxis (PrEP) for HIV Prevention. 2023. https://www.cdc.gov/hiv/basics/prep.html
- Cleveland Clinic. When to Seek Emergency Care for HIV‑Related Problems. 2024. https://my.clevelandclinic.org/health/diseases/17348-hiv-aids-emergency-symptoms