Human Immunodeficiency Virus (HIV) infection, if left unaddressed, progresses from an initial acute phase into a chronic condition that gradually weakens the immune system by attacking CD4+ T cells. This immune deficiency can ultimately lead to Acquired Immunodeficiency Syndrome (AIDS), a life-threatening stage of HIV infection.
However, the landscape of HIV has been transformed by effective antiretroviral therapy (ART). ART can suppress HIV to undetectable levels, dramatically improving the health and lifespan of individuals living with HIV and preventing onward sexual transmission. Early HIV diagnosis is the cornerstone of this success, enabling prompt linkage to care and initiation of ART. Both the U.S. Department of Health and Human Services and the International AIDS Society–USA Panel emphasize immediate ART for all diagnosed individuals, underscoring its dual benefit for personal health and public health by curbing transmission.
STD clinics and sexual health centers play a critical role in HIV prevention and diagnosis, particularly for vulnerable populations who may not access traditional healthcare settings. The presence of a sexually transmitted infection (STI) is a significant indicator of potential HIV acquisition risk. While STD clinics conduct a smaller proportion of federally funded HIV tests compared to other venues, they identify a disproportionately high percentage of new HIV infections. Notably, STD clinics excel at linking newly diagnosed individuals to HIV care promptly, with rates exceeding 90% within 90 days of diagnosis, highlighting their efficiency in facilitating the crucial early steps of HIV management.
Recommended HIV Screening Practices
To enhance early detection efforts, the following HIV testing guidelines are broadly recommended:
- Routine STI Evaluation: HIV testing is a standard recommendation for all individuals seeking STI evaluation who do not have a known HIV diagnosis. This testing should be integrated into the routine STI evaluation process, irrespective of reported HIV risk behaviors. If not performed initially, HIV testing should occur at the time of STI diagnosis and treatment.
- Universal Screening Recommendations: The CDC and USPSTF advocate for HIV screening at least once in the lifetime for all individuals between 15 and 65 years of age.
- Frequent Screening for High-Risk Groups: Individuals at heightened risk of HIV acquisition, notably sexually active gay, bisexual, and other men who have sex with men (MSM), should undergo HIV screening at least annually. More frequent screening (e.g., every 3–6 months) may be beneficial for MSM with multiple risk factors.
- Prenatal Screening: All pregnant women should be tested for HIV during their first prenatal visit. A repeat test in the third trimester, ideally before 36 weeks gestation, is also recommended to further minimize the risk of perinatal HIV transmission.
- Voluntary and Informed Testing: HIV screening must be voluntary and free from coercion. Testing should not proceed without the individual’s knowledge.
- Opt-Out Screening: An opt-out approach to HIV screening, where patients are informed that an HIV test will be performed unless they decline, is recommended across all healthcare settings. The CDC advises incorporating consent for HIV screening within the general consent for medical care, similar to other routine tests.
- Elimination of Specific Signed Consent: Requiring specific signed consent for HIV testing is not necessary. General informed consent for medical care adequately covers informed consent for HIV testing.
- Laboratory-Based Antigen/Antibody (Ag/Ab) Combination Assay as Initial Test: Providers should utilize a laboratory-based Ag/Ab combination assay as the first-line HIV screening test. Rapid point-of-care (POC) tests may be considered when follow-up for results is uncertain.
- Supplemental Testing for Reactive Screening Tests: Preliminary positive HIV screening results must be confirmed with supplemental laboratory testing to establish a definitive diagnosis.
- Prevention Counseling as an Adjunct: While not mandatory alongside HIV screening or diagnostic testing, prevention counseling is valuable. The testing encounter provides an opportune moment for providers to discuss STI and HIV prevention and reinforce risk-reduction strategies.
- Consideration of Acute HIV Infection: Acute HIV infection should be considered in individuals reporting recent sexual or needle-sharing risk behaviors or those diagnosed with an STI.
- HIV RNA Testing for Suspected Acute Infection: In cases of suspected acute HIV infection, especially when initial Ag/Ab tests are negative or indeterminate, HIV RNA testing is recommended.
- Explicit Request for HIV RNA Testing: Providers should not assume that a negative Ag/Ab or antibody test report includes HIV RNA testing. Explicitly requesting HIV RNA testing is crucial when acute HIV infection is a concern.
- Assessment for HIV PrEP and PEP Eligibility: Providers should assess all individuals seeking STI services for their eligibility for HIV pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP). PrEP referral should be offered to HIV-negative individuals at substantial risk, while PEP should be considered if a recent HIV exposure has occurred.
Diagnostic Algorithm: The CDC’s Recommended Approach
The diagnosis of HIV infection relies on highly sensitive and specific HIV 1/2 Ag/Ab combination immunoassays. These FDA-approved tests are capable of detecting all known HIV-1 subtypes, as well as HIV-2 and less common HIV-1 variants.
The CDC recommends a specific algorithm for HIV diagnosis, initiating with a laboratory-based HIV-1/HIV-2 Ag/Ab combination assay. If this initial assay is repeatedly reactive, it is followed by a supplemental laboratory-based HIV-1/HIV-2 antibody differentiation assay.
Alt Text: CDC recommended algorithm for HIV diagnosis, starting with combination antigen/antibody immunoassay, followed by antibody differentiation assay and nucleic acid test (NAT) for discordant results or acute infection.
This diagnostic algorithm offers several advantages. Firstly, it detects both HIV-1 and HIV-2 antibodies in the supplemental assay, which is crucial for accurate diagnosis, especially as HIV-2, although less prevalent in the United States, requires distinct monitoring and treatment strategies compared to HIV-1. Secondly, for specimens with a reactive immunoassay but a negative supplemental antibody test, RNA testing is recommended. This step is critical to identify potential acute HIV infection cases. Discordant results like these can occur during the window period between HIV acquisition and antibody development.
Rapid POC HIV tests serve as valuable tools for preliminary HIV diagnosis, especially in settings where immediate results are needed or follow-up for lab results is a concern. However, it’s important to remember that reactive rapid tests still require laboratory confirmation using the full CDC algorithm.
Acute HIV Infection: A Diagnostic Challenge
Healthcare providers in STI clinics and similar settings are uniquely positioned to diagnose HIV infection during its acute phase. Diagnosing acute HIV infection is of paramount importance due to the extremely high viral load present in plasma and genital secretions during this stage, making individuals significantly more infectious.
Initiating ART during acute HIV infection is highly recommended. It offers multiple benefits, including a substantial reduction in transmission risk, improved disease markers, potential mitigation of acute illness severity, lowering the viral set point, reducing the viral reservoir size, decreasing viral mutation rates through replication suppression, and preserving immune function. Individuals diagnosed with acute HIV should be immediately linked to specialized HIV care, receive comprehensive prevention counseling (emphasizing partner reduction and consistent condom use), and be screened for other STIs. Furthermore, offering PEP to sexual or injecting drug use partners without known HIV infection should be considered if recent exposure occurred.
It’s critical to recognize that specimens collected during acute HIV infection may yield indeterminate or negative results when using the standard CDC algorithm. This is because antibody levels, and sometimes antigen levels, may be insufficient to trigger reactivity in Ag/Ab combination assays and antibody differentiation assays in the very early stages of infection. Therefore, when acute HIV infection is suspected—particularly following recent potential HIV exposure (within days to weeks) and in the presence of symptoms or other STIs like syphilis, gonorrhea, or chlamydia—HIV RNA testing is essential, even if initial algorithm tests are negative or indeterminate. If HIV RNA testing is also negative in suspected acute infection, repeat testing within a few weeks is advised to rule out very early infection where RNA levels might be initially undetectable.
HIV Treatment: Immediate and Universal
For all individuals diagnosed with HIV, ART initiation should be as swift as possible, irrespective of CD4+ T-cell count. This recommendation is driven by the dual goals of optimizing individual health outcomes and preventing further HIV transmission.
Individuals who achieve and maintain viral suppression through ART to undetectable levels not only experience significantly improved health but also eliminate the risk of sexual HIV transmission to their partners. Early HIV diagnosis and subsequent treatment serve as a critical public health intervention to curb new infections. Understanding the prevention benefits of treatment can reduce stigma associated with HIV and enhance an individual’s commitment to ART adherence. While ART is transformative, it’s crucial to emphasize that it does not protect against other STIs, underscoring the continued importance of consistent condom use for STI prevention. Comprehensive interventions are available to support individuals in adhering to their prescribed ART regimens, minimizing transmission risks, and protecting themselves from other STIs.
Facilities primarily focused on STI treatment may not offer comprehensive HIV treatment and care services. Therefore, providers in these settings must possess knowledge of HIV care options within their communities and ensure prompt linkage to specialized HIV care for newly diagnosed individuals and those not engaged in effective ongoing care.
Comprehensive HIV Management Beyond Diagnosis
Effective HIV care extends beyond medical treatment and encompasses behavioral and psychosocial support. Receiving an HIV diagnosis can be emotionally challenging, and individuals may face stigma, require support in adapting to their condition, and need to develop strategies for maintaining their physical and emotional well-being. This includes behavior changes to prevent HIV transmission and reduce the risk of acquiring other STIs. Many individuals will require assistance in accessing healthcare, support services, and navigating changes in personal relationships.
Furthermore, individuals with HIV may have co-occurring needs such as substance use disorders or mental health conditions. Support with employment, housing, and family planning are also crucial components of holistic HIV care.
Key recommendations for managing individuals diagnosed with HIV infection include:
- Immediate Linkage to Care and ART Initiation.
- Reporting cases to public health authorities and initiating partner services as per local regulations.
- Providing prevention counseling.
- Educating individuals about the elimination of sexual transmission risk with sustained viral suppression, while emphasizing that ART does not prevent other STIs.
- Offering psychosocial and medical counseling and support services, either on-site or through referral.
- Assessing immediate medical and psychosocial needs.
- Linking individuals to experienced HIV care providers and support services, including substance misuse and mental health treatment, reproductive counseling, risk-reduction counseling, and case management, with follow-up to ensure service uptake.
- Educating individuals about the importance of ongoing HIV medical care.
STI Screening in HIV Care Settings
For individuals receiving HIV care, routine STI screening is essential. At the initial HIV care visit, all sexually active individuals should be screened for syphilis, gonorrhea, and chlamydia, with annual screening thereafter. Testing should include syphilis serology and NAAT for N. gonorrhoeae and C. trachomatis at relevant anatomical sites. Women should also be screened for trichomoniasis at the initial visit and annually. Cervical cancer screening should follow established guidelines.
More frequent STI screening (e.g., every 3–6 months) may be indicated based on individual risk factors and local STI prevalence. Asymptomatic STIs are common, and their diagnosis can trigger partner services, identify undiagnosed HIV cases among partners, and facilitate re-engagement in HIV prevention or care services.
Partner Services and Reporting: A Public Health Imperative
Partner notification is a vital component of HIV care. Early diagnosis and treatment of HIV in potentially exposed sexual and injecting drug-sharing partners improve their health and reduce onward transmission. For uninfected partners, partner services offer access to HIV prevention strategies like PrEP or PEP.
Healthcare providers should inform individuals with HIV about reporting obligations, confidential partner services processes, and the benefits and risks of partner notification. Encouraging individuals to notify their partners and providing referral information for HIV testing is crucial. Partner notification for HIV exposure must be confidential. Health departments are equipped to confidentially locate and support individuals who can benefit from HIV treatment, care, or prevention services.
Special Considerations: Pregnancy and Neonates
Pregnancy
Universal HIV testing during pregnancy is critical. All pregnant women should be tested during the first prenatal visit, with a repeat test in the third trimester. The HIV diagnostic algorithm for pregnant women is the same as for non-pregnant individuals. Pregnant women should be informed about routine prenatal HIV testing and counseled about the benefits of testing for their health and for preventing perinatal HIV transmission. Retesting in each pregnancy is important, even with prior negative results. Women presenting in labor without prenatal care should be tested for HIV at delivery.
Alt Text: Illustration of a pregnant woman getting blood drawn by a doctor for prenatal testing, emphasizing routine care during pregnancy.
Knowledge of HIV status during pregnancy is crucial for maternal health and for implementing interventions like ART to minimize perinatal HIV transmission risk. Without ART, mother-to-child HIV transmission risk is significant, but ART can reduce this risk dramatically. Pregnant women with HIV should be linked to specialized HIV care and receive antenatal and postpartum treatment and guidance.
HIV Infection Among Neonates, Infants, and Children
Diagnosing HIV in a pregnant woman necessitates evaluation and management of the HIV-exposed neonate and consideration of testing other children of the mother. Neonates and children with HIV should be referred to pediatric HIV specialists.
By adhering to the CDC’s HIV diagnostic algorithm and comprehensive guidelines, healthcare providers can play a pivotal role in early HIV detection, ensuring prompt access to care and treatment, and ultimately contributing to both individual well-being and broader public health goals of HIV prevention and control.
