Human immunodeficiency virus (HIV) infection - Symptoms, Causes, Treatment & Prevention

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Overview

Human immunodeficiency virus (HIV) is a retrovirus that attacks the body’s immune system, specifically CD4⁺ T‑lymphocytes, which are crucial for fighting infections. If left untreated, HIV progressively destroys these cells, leading to acquired immunodeficiency syndrome (AIDS).

• Who it affects: Anyone can become infected, regardless of age, gender, sexual orientation, or socioeconomic status. However, certain groups have higher prevalence rates, including men who have sex with men (MSM), heterosexual women in sub‑Saharan Africa, people who inject drugs, and transgender individuals.
• Global prevalence: According to the World Health Organization (WHO), about 38 million people worldwide were living with HIV in 2023, with roughly 1.5 million new infections each year.<sup>1</sup>
• U.S. prevalence: The Centers for Disease Control and Prevention (CDC) estimates ~1.2 million Americans are living with HIV, and approximately 13% are unaware of their infection.<sup>2</sup>

Symptoms

HIV infection can be divided into three clinical stages, each with its own symptom profile. Some people remain asymptomatic for years, especially with early antiretroviral therapy (ART).

1. Acute HIV infection (2‑4 weeks after exposure)

• Fever
• Headache
• Sore throat
• Rash (often maculopapular, on trunk)
• Muscle and joint aches
• Swollen lymph nodes
• Diarrhea, nausea, or vomiting
• Fatigue

These symptoms resemble a mild flu and are sometimes called “seroconversion illness.” They typically last 1‑2 weeks.

2. Clinical latency (chronic HIV infection)

• Often no symptoms, especially with effective ART.
• Possible mild, intermittent issues: low‑grade fever, night sweats, weight loss, or persistent swollen lymph nodes.

3. AIDS‑defining illnesses (advanced HIV)

• Rapid weight loss (≥10% of body weight)
• Recurring fever >38°C (100.4°F) for >3 weeks
• Profuse night sweats
• Extreme and unexplained fatigue
• Chronic diarrhea (lasting >1 month)
• Severe or persistent opportunistic infections (e.g., Pneumocystis jirovecii pneumonia, cryptococcal meningitis)
• Kaposi sarcoma or other cancers
• Neurological disorders (e.g., HIV‑associated dementia, peripheral neuropathy)

Causes and Risk Factors

HIV is transmitted through contact with infected bodily fluids—blood, semen, vaginal secretions, rectal fluids, and breast milk. The virus cannot survive long outside the body, so casual contact (handshakes, sharing dishes, or using public toilets) is not a risk.

Primary modes of transmission

• Unprotected sexual intercourse: Vaginal, anal, or oral sex without a condom or pre‑exposure prophylaxis (PrEP).
• Injection drug use: Sharing needles, syringes, or other injection equipment.
• Mother‑to‑child transmission: During pregnancy, childbirth, or breastfeeding (reduced to <1% with proper ART).
• Blood transfusion or organ transplant: Rare in countries with rigorous screening.

Risk factors

• Having multiple sexual partners or a partner with unknown HIV status.
• Having other sexually transmitted infections (STIs) that cause ulcerative lesions.
• Engaging in unprotected anal sex (higher risk than vaginal).
• Sharing injection equipment.
• Inconsistent use of PrEP or post‑exposure prophylaxis (PEP).
• Being in a geographic area with high community prevalence.

Diagnosis

Early diagnosis is essential for prompt treatment and preventing transmission.

Screening tests

• Fourth‑generation HIV antigen/antibody combo assay: Detects both HIV‑1/2 antibodies and p24 antigen; can identify infection as early as 2–4 weeks post‑exposure.
• Rapid point‑of‑care tests: Finger‑stick or oral fluid tests that give results in 20–30 minutes; must be confirmed with a laboratory test.

Confirmatory testing

• HIV‑1/HIV‑2 differentiation immunoassay (e.g., Geenius) to distinguish the virus type.
• HIV RNA PCR (viral load) test: Detects viral genetic material; used when acute infection is suspected and antibody tests may be negative.

Baseline evaluation after a positive result

• CD4⁺ T‑cell count (immune status).
• HIV viral load (copies/mL).
• Screening for hepatitis B, hepatitis C, and syphilis.
• Resistance testing (genotypic) to guide initial ART regimen.

Treatment Options

Modern HIV care relies on combination antiretroviral therapy (cART), which suppresses viral replication, restores immune function, and prevents progression to AIDS.

First‑line ART regimens (2024 CDC/WHO guidelines)

• Integrase strand transfer inhibitor (INSTI)‑based regimens:
  • Dolutegravir + Tenofovir disoproxil fumarate (TDF) + Emtricitabine (FTC)
  • Bictegravir + TAF (tenofovir alafenamide) + FTC
• These regimens are taken once daily, have high barriers to resistance, and are well‑tolerated.

Special scenarios

• Pregnancy: Regimens containing dolutegravir or bictegravir are now recommended, with careful counseling about neural‑tube defect risk in the first trimester.<sup>3</sup>
• Renal or hepatic impairment: Adjust dosing or select alternatives (e.g., avoiding TDF in severe renal disease).
• Co‑infection with hepatitis B: Use agents active against both viruses (e.g., TDF/TAF + FTC or lamivudine).

Adjunctive care

• Vaccinations (influenza, COVID‑19, pneumococcal, HPV, hepatitis A/B).
• Prophylaxis for opportunistic infections when CD4 <200 cells/µL (e.g., TMP‑SMX for Pneumocystis jirovecii).
• Regular monitoring: CD4 count & viral load every 3–6 months once stable.

Lifestyle modifications

• Adopt a balanced diet rich in fruits, vegetables, lean protein, and whole grains.
• Engage in regular physical activity (≥150 min moderate‑intensity aerobic exercise per week).
• Avoid smoking and limit alcohol consumption.
• Maintain mental health through counseling, support groups, or therapy.

Living with Human Immunodeficiency Virus (HIV) infection

With effective ART, people living with HIV (PLWH) can expect near‑normal life expectancy. Successful management hinges on routine care and self‑advocacy.

Daily management tips

• Medication adherence: Take ART at the same time each day; use pillboxes, phone alarms, or mobile apps.
• Track lab results: Keep a personal health record of CD4 counts and viral loads; aim for an undetectable viral load (<20‑50 copies/mL).
• Stay informed: Attend regular appointments, discuss any side effects, and ask about drug‑drug interactions.
• Sexual health: Use condoms consistently; discuss PrEP/PEP with partners; disclose HIV status to sexual partners as legally required.
• Psychosocial support: Connect with local or online support groups (e.g., AIDS Service Organizations).
• Emergency contacts: Carry a medical ID card indicating HIV status and current ART regimen.

Prevention

Preventing HIV acquisition and transmission involves biomedical, behavioral, and structural strategies.

Biomedical interventions

• Pre‑exposure prophylaxis (PrEP): Daily oral TDF/FTC (Truvada) or TAF/FTC (Descovy) reduces risk by >90% when taken consistently.
• Post‑exposure prophylaxis (PEP): A 28‑day course of ART started within 72 hours after a high‑risk exposure.
• Treatment as prevention (TasP): Achieving and maintaining an undetectable viral load prevents sexual transmission (U=U statement).
• Voluntary medical male circumcision: Lowers heterosexual acquisition risk by ~60%.

Behavioral strategies

• Consistent condom use (male or female condoms).
• Limiting number of sexual partners and choosing low‑risk partners.
• Avoiding sharing needles or injection equipment.
• Regular STI screening and treatment.

Structural approaches

• Access to affordable testing and treatment services.
• Comprehensive sex education in schools and communities.
• De‑stigmatizing policies that encourage people to seek care.

Complications

If HIV is not adequately suppressed, the immune system deteriorates, leading to a spectrum of complications.

• Opportunistic infections (OIs): Pneumocystis jirovecii pneumonia, Mycobacterium avium complex, cytomegalovirus retinitis, cryptococcal meningitis, and recurrent herpes simplex.
• HIV‑associated neurocognitive disorders (HAND): Ranges from mild impairment to severe dementia.
• Cardiovascular disease: Higher rates of myocardial infarction and stroke, partly due to chronic inflammation.
• Kidney disease: HIV‑associated nephropathy and drug‑related nephrotoxicity.
• Liver disease: Co‑infection with hepatitis B/C and ART‑related hepatotoxicity.
• Malignancies: Kaposi sarcoma, non‑Hodgkin lymphoma, invasive cervical cancer.
• Bone density loss: Osteopenia/osteoporosis, especially with tenofovir‑based regimens.

When to Seek Emergency Care

References

1. World Health Organization. Global HIV & AIDS statistics — 2023 fact sheet. WHO; 2023. https://www.who.int/news-room/fact-sheets/detail/hiv-aids
2. Centers for Disease Control and Prevention. HIV Surveillance Report, 2023. CDC; 2024. https://www.cdc.gov/hiv/library/reports/hiv-surveillance.html
3. U.S. Department of Health & Human Services. Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV. 2024. https://clinicalinfo.hiv.gov/en/guidelines
4. Mayo Clinic. HIV/AIDS – Symptoms and causes. Mayo Foundation; 2023. https://www.mayoclinic.org/diseases-conditions/hiv-aids/symptoms-causes/syc-20373524
5. Cleveland Clinic. HIV Treatment and Lifestyle Management. Cleveland Clinic; 2023. https://my.clevelandclinic.org/health/diseases/15857-hiv-aids

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