HIV Infection (Acute & Chronic)

Infectious Disease

Description

HIV infection is a progressive systemic retroviral disease caused by human immunodeficiency virus type 1 (globally dominant) or type 2 (West Africa–centric). The virus targets CD4⁺ T lymphocytes, monocytes–macrophages, and dendritic cells, producing an initial flu-like acute retroviral syndrome, an often protracted clinically latent stage with ongoing immunologic deterioration, and, without antiretroviral therapy, advanced infection culminating in acquired immunodeficiency syndrome (AIDS). Effective modern combination antiretroviral therapy suppresses plasma viremia to undetectable levels, restores immune function, prevents sexual and perinatal transmission (Undetectable = Untransmittable), and transforms HIV into a manageable chronic condition.

Symptoms

Acute infection (typically 2–4 weeks after exposure) presents with abrupt fever, pharyngitis, lymphadenopathy, maculopapular trunk rash, night sweats, myalgia, arthralgia, mucosal ulcers, diarrhoea, or aseptic meningitis; symptoms last 1–3 weeks and often prompt no testing. Early chronic infection is usually asymptomatic but may manifest persistent generalized lymphadenopathy. Late chronic infection produces weight loss, chronic diarrhoea, oral candidiasis, herpes zoster, recalcitrant seborrhoeic dermatitis, and cytopenias as CD4⁺ count declines. AIDS (CD4 < 200 cells/µL or an AIDS-defining condition) features opportunistic infections—Pneumocystis jirovecii pneumonia, cryptococcal meningitis, toxoplasmic encephalitis, cytomegalovirus retinitis—or malignancies such as Kaposi sarcoma, non-Hodgkin lymphoma, and invasive cervical cancer. Chronic immune activation also drives cardiovascular disease, neurocognitive impairment, renal dysfunction, and bone loss despite immune reconstitution.

Risk Factors

Condomless receptive or insertive anal or vaginal intercourse with an infected partner; presence of other sexually transmitted infections (ulcerative diseases, bacterial vaginosis); multiple partners; transactional sex; injection-drug use with shared needles or paraphernalia; non-sterile medical or tattoo procedures; needle-stick injury; perinatal exposure (in utero, intrapartum, or breast-feeding) to a viraemic mother; transfusion of unscreened blood products; incarceration; homelessness; adolescent or young adult status with high-risk behaviours; and lack of access to pre-exposure prophylaxis or comprehensive prevention services. Genetic deletion CCR5-Δ32 confers relative resistance.

Diagnosis

Fourth-generation combination immunoassays detect HIV-1/2 antibodies and p24 antigen within 18–45 days post-exposure and are the recommended screening test. Reactive results reflex to a discriminatory antibody differentiation assay; discordant or indeterminate results undergo plasma HIV-1 RNA PCR. During the eclipse phase (first 7–10 days post-exposure) only RNA is positive. A quantitative viral load establishes baseline viremia; CD4⁺ T-cell count gauges immune status. Additional baseline evaluation includes HIV-1 genotype for resistance and tropism, complete blood count, metabolic panel, fasting lipid/glucose, hepatitis A/B/C serologies, tuberculosis screening, STI panel, pregnancy test, and HLA-B*57:01 for abacavir hypersensitivity.

Treatment

Antiretroviral therapy is recommended for all persons at diagnosis, irrespective of CD4⁺ count, and ideally initiated the same day (“rapid start”). First-line regimens consist of two nucleoside reverse-transcriptase inhibitors (NRTIs) plus a high-barrier third agent: Tenofovir alafenamide-emtricitabine combined with either the integrase-strand-transfer-inhibitor (INSTI) bictegravir (single tablet), dolutegravir, or, when INSTI contraindicated, boosted darunavir. In selected patients, once-daily dolutegravir-lamivudine dual therapy is acceptable if viral load < 500 000 copies/mL, no HBV co-infection, and resistance results pending. INSTI-based regimens suppress viremia to < 50 copies/mL in > 95 % within six months with excellent tolerability. Lifelong adherence is essential. Opportunistic-infection prophylaxis—trimethoprim-sulfamethoxazole when CD4 < 200 cells/µL, azithromycin at CD4 < 50 in high-Mycobacterium avium locales—continues until immune recovery. Vaccinations (HAV, HBV, HPV, pneumococcal, influenza, COVID-19, Mpox where indicated) are updated. Long-acting injectable cabotegravir-rilpivirine every 8 weeks after oral lead-in offers an alternative for suppressed adults. Acute retroviral syndrome managed with immediate ART limits reservoir seeding and preserves immunity.

Outlook

With sustained suppression, life expectancy now approaches that of HIV-negative peers, although earlier mortality from cardiovascular, liver, renal, and non-AIDS cancers persists. Viral suppression prevents sexual transmission (U = U) and reduces vertical transmission risk to < 1 % when maternal viral load is undetectable at delivery. Delayed diagnosis or poor adherence leads to immunodeficiency, opportunistic disease, and higher mortality.

Complications

Opportunistic infections (PCP, MAC, tuberculosis, cryptococcosis, histoplasmosis), AIDS-defining malignancies (Kaposi sarcoma, high-grade B-cell lymphomas, invasive cervical cancer), immune reconstitution inflammatory syndrome after ART initiation, HIV-associated neurocognitive disorder, HIV-associated nephropathy, premature atherosclerotic cardiovascular disease, osteoporosis and fractures, chronic liver disease from HBV/HCV coinfection, lipodystrophy and metabolic syndrome from certain ARTs, and psychological disorders are recognised sequelae.

Prevention

Primary prevention includes condom use; treatment as prevention (U = U); daily oral pre-exposure prophylaxis with tenofovir disoproxil fumarate-emtricitabine or long-acting injectable cabotegravir for high-risk HIV-negative persons; harm-reduction needle-exchange and opioid-substitution programs; voluntary medical male circumcision; and post-exposure prophylaxis (three-drug ART for 28 days within 72 h of exposure). Universal prenatal screening, viral suppression during pregnancy, intrapartum zidovudine, and formula feeding (in high-income settings) prevent perinatal transmission.

Support

Take antiretroviral pills or attend injection appointments exactly as prescribed, use electronic reminders or pillboxes, attend clinic and laboratory monitoring every three to six months, notify providers before starting new medications or supplements to avoid interactions (e.g., with rifampin, anticonvulsants, St John’s wort), maintain healthy diet and exercise, cease smoking, limit alcohol, and pursue mental-health or substance-use counselling as needed. Disclosure to sexual partners enables their testing and prophylaxis; consistent condom use protects against other STIs. Pregnant individuals require obstetric-infectious disease co-management and neonatal prophylaxis for the infant.