HIV and AIDS

For diagnostic testing, CDC recommends beginning with a laboratory-based HIV-1/HIV-2 antigen-antibody combination immunoassay. A repeatedly reactive specimen should undergo a laboratory HIV-1/HIV-2 antibody differentiation assay. This sequence identifies HIV-2 antibodies, a clinically important distinction because HIV-2 monitoring and therapy differ from HIV-1.CDCCDCHIV - STI Treatment Guidelines

If the initial immunoassay is reactive but the supplemental antibody differentiation assay is negative, obtain HIV RNA testing. This discordant pattern can represent acute HIV infection rather than a false-positive screening result.CDCCDCHIV - STI Treatment Guidelines

Acute retroviral syndrome may occur 1 to 6 weeks after acquisition and can include fever, rash, myalgias, headache, or gastrointestinal symptoms. In a patient with compatible illness and recent exposure, a negative or indeterminate antibody-based result should not end the evaluation; obtain virologic testing when acute infection is plausible.ScienceDirect+1ScienceDirectAcute HIV Infection - an overviewCDCHIV - STI Treatment Guidelines

CDC states that effective ART suppressing HIV replication to undetectable levels reduces morbidity, enables near-normal lifespan, and prevents sexual transmission. U.S. Department of Health and Human Services and International Antiviral Society–USA recommendations support offering effective ART as soon as possible to all persons with HIV, both for patient benefit and prevention of transmission.CDCCDCHIV - STI Treatment Guidelines

The supplied evidence supports rapid ART linkage but does not provide regimen-specific dosing, resistance-testing requirements, renal or hepatic selection criteria, drug-interaction management, or laboratory monitoring schedules. Confirm these details in current HHS antiretroviral guidelines and product labeling before prescribing.

For a new acute HIV diagnosis, arrange immediate HIV specialty linkage, screen for STIs, and provide prevention counseling. Counsel patients to reduce partner number and use condoms correctly and consistently while diagnostic evaluation and viral suppression are being established.CDCCDCHIV - STI Treatment Guidelines

CD4 count is an important laboratory indicator of immune function and a predictor of disease progression. Opportunistic-infection risk rises as CD4 declines, particularly below 200 cells/µL or when CD4 percentage is below 14%.Nature+1NatureRobustness of viral load over CD4 cell count in measuring the quality of life of people with HIV at second line regimen in Amhara region | Scientific ReportsScienceDirectRoutine CD4 monitoring in HIV patients with viral ...

Profound immunosuppression predicts pathogen-specific vulnerability. Most Pneumocystis jirovecii pneumonia occurs with CD4 counts below 200 cells/µL, whereas cytomegalovirus retinitis typically occurs below 50 cells/µL.ScienceDirectScienceDirectAcute HIV Infection - an overview These thresholds should prompt review of current opportunistic-infection prophylaxis, diagnostic, and treatment guidance; specific prophylactic regimens are not supplied in the available evidence.

The practical distinction between HIV infection and advanced disease is therefore not merely semantic: immune status changes the differential diagnosis, urgency of symptom evaluation, and need to apply opportunistic-infection prevention guidance. Maintain a low threshold to evaluate compatible pulmonary, neurologic, ocular, constitutional, or mucocutaneous presentations in patients with low CD4 counts.ScienceDirect+1ScienceDirectRoutine CD4 monitoring in HIV patients with viral ...ScienceDirectAcute HIV Infection - an overview

PrEP is an evidence-based strategy for people at ongoing risk of HIV acquisition. CDC's 2021 clinical practice guideline provides comprehensive guidance for PrEP in adults and adolescents, and CDC now lists a 2025 clinical recommendation for subcutaneous lenacapavir administered every 6 months for HIV PrEP.CDC+1CDCGuidelines and Recommendations | HIV NexusCDCPreexposure Prophylaxis for the Prevention of HIV Infection in the United States – 2021 Update: A Clinical Practice Guideline The supplied excerpts do not provide eligibility criteria, baseline testing, follow-up intervals, or dosing for oral PrEP; consult the current CDC PrEP guidance and FDA labeling for regimen selection and monitoring.

Randomized evidence supports the preventive efficacy of antiretroviral PrEP in women at risk for HIV-1 infection.The LancetThe Lancetresults from HPTN 084, a phase 3, randomised clinical trial Adherence is a major determinant of protection with oral PrEP; evidence summarized in a recent trial report notes diminished protection below 40% adherence, although that specific threshold should not substitute for guideline-based adherence assessment or regimen selection.NatureNatureReal-time digital intervention on oral pre-exposure prophylaxis adherence among MSM: randomized controlled trial | npj Digital Medicine

For a discrete recent exposure, PEP is time sensitive. CDC advises that partners of an individual newly diagnosed with acute HIV should be informed about PEP when their most recent sexual or injection-drug-use contact occurred less than 72 hours earlier.CDCCDCHIV - STI Treatment Guidelines