Acute HIV infection
Acute HIV infection, also called the acute retroviral syndrome, is the symptomatic viremic phase in the days to weeks after HIV acquisition, presenting with fever, fatigue, myalgia, rash, and pharyngitis at a time when antibody testing may still be negative. Diagnosis requires an HIV RNA viral load, and antiretroviral therapy should begin as soon as the patient is ready, regardless of CD4 count.
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What this article covers
- Overview
Acute HIV infection is the symptomatic phase of early, high-level HIV viremia: it occurs days to weeks after HIV acquisition, before a detectable antibody response, and is also called the acute retroviral syndrome.
- Epidemiology
A substantial proportion of persons with HIV do not know their status: many have never been tested, and the undiagnosed and not-in-care population accounted for the majority of ongoing HIV transmissions in recent CDC estimates.
- Risk factors
A serodiscordant sexual partner with an unsuppressed or unknown viral load: the single strongest risk factor, since a suppressed source partner carries near-zero transmission risk ("Undetectable = Untransmissible").
- Pathophysiology
HIV establishes infection at a mucosal or parenteral portal of entry and disseminates rapidly: the virus infects CD4 (helper) T cells and disseminates systemically, producing a burst of very high plasma viremia during the acute phase.
- Clinical features
Fever is the most common feature (about 75% of symptomatic cases), part of a nonspecific viral-syndrome/mononucleosis-like picture.
- Differential diagnosis
Infectious mononucleosis (Epstein-Barr virus): infectious mononucleosis overlaps on fever, pharyngitis, lymphadenopathy, and rash; a positive heterophile antibody/EBV serology with negative HIV RNA confirms EBV.
- Diagnosis
The clinching diagnostic step is a positive HIV-1 RNA viral load (nucleic acid amplification test, NAAT) in a patient whose fourth-generation antigen/antibody screen is negative or indeterminate…
- Management
Begin antiretroviral therapy (ART) as soon as the patient is ready, regardless of CD4 cell count: waiting for CD4 decline provides no benefit and exposes the patient to AIDS and non-AIDS-related harm.
- Complications
Ongoing high-risk transmission during the unrecognized acute window: the highest plasma viral load and per-exposure transmissibility of any stage, so a missed diagnosis has direct public health consequences.
- Prognosis
Excellent with early diagnosis and prompt ART initiation: modern regimens durably suppress viral replication and allow near-normal life expectancy with adherence.
- Prevention
Universal HIV screening at least once for all adults, with annual (or every 3-6 months for some higher-risk men who have sex with men) repeat screening for those at ongoing risk.
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