What is the best strategy to prevent new Human Immunodeficiency Virus (HIV) acquisitions?

Best Strategy to Prevent New HIV Acquisitions

The most effective strategy to prevent new HIV acquisitions is a combination approach integrating pre-exposure prophylaxis (PrEP) for high-risk individuals, immediate antiretroviral therapy (ART) for all HIV-infected persons to achieve viral suppression, and harm reduction services for people who inject drugs, supplemented by behavioral risk reduction counseling. 1

Core Prevention Framework

The integration of biomedical and behavioral approaches represents the cornerstone of HIV prevention efforts, with evidence demonstrating that no single intervention alone will be sufficient to contain HIV spread. 1, 2

For HIV-Uninfected High-Risk Individuals

Daily oral emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) is the recommended PrEP regimen for all populations at high risk of HIV acquisition. 1 High-risk populations requiring prioritization include:

• Cisgender men, transgender persons, and nonbinary persons who have sex with cisgender men 1
• Individuals with recent sexually transmitted infections (STIs) 1
• People who inject drugs or share needles 1
• Young adults and adolescents up to age 24 years 1
• Persons whose sexual partners are from regions with high HIV incidence 1
• Anyone requesting PrEP, without requiring specific behavioral criteria 1

The key determinant of PrEP efficacy is medication adherence—detection of tenofovir in plasma has been associated with approximately 90% reduction in HIV acquisition, while drug levels consistent with daily use show an estimated 99% reduction in HIV risk. 1 Conversely, trials where tenofovir was detected in less than 30% of participants showed no efficacy. 1

For HIV-Infected Individuals

All persons diagnosed with HIV should be immediately linked to care for timely initiation of ART, regardless of CD4 count. 1 Rapid viral suppression eliminates sexual transmission of HIV (undetectable = untransmittable, or U = U). 1 This "treatment as prevention" (TasP) strategy has a number needed to treat (NNT) of 34 at 42 months, making it one of the most effective prevention interventions. 3

For People Who Inject Drugs

Simultaneous scale-up of harm reduction services—including needle and syringe exchange programs, opioid substitution therapy (especially methadone), and ART access—can reduce HIV incidence among people who inject drugs by greater than 90%. 1, 4 This combination is supported by WHO, UNODC, and UNAIDS technical guidelines. 1, 4

A population-based analysis in British Columbia demonstrated a province-wide decline in new HIV diagnoses of greater than 90%, largely attributed to expanded harm reduction programs coupled with enhanced ART coverage among people who inject drugs. 1, 4 Opioid substitution therapy increases the likelihood that people who inject drugs will initiate ART and improves adherence once initiated. 1, 4

Essential Behavioral Components

Individualized risk reduction counseling using motivational interviewing and skills-based approaches should be provided to all patients, with an NNT of 11 at 12 months—among the lowest of all prevention interventions. 1, 3 Effective counseling fosters self-belief, distinguishes fact from myth, promotes self-control, and teaches negotiation of safer behaviors. 1

Condoms remain a cornerstone of prevention for all penetrative sex acts to reduce acquisition of STIs, including HIV. 1

Critical Testing and Screening Strategy

HIV testing is recommended at least once for all adults and adolescents, with repeated testing for those at increased risk. 1 At PrEP initiation or after a long hiatus, HIV screening should include both an HIV RNA test and a laboratory-based antigen-antibody test to rule out acute infection. 1 This is crucial because starting PrEP during acute HIV infection can lead to drug resistance. 1

Quarterly STI screening of contact sites and blood syphilis testing is recommended for all persons on PrEP. 1 Early detection and treatment of curable STDs (chlamydia, gonorrhea, syphilis, chancroid) represents a major component of comprehensive HIV prevention, as these infections increase HIV transmission risk by twofold to fivefold. 1

Emerging Bacterial STI Prevention

Doxycycline post-exposure prophylaxis (doxyPEP) at 200 mg within 72 hours after condomless sex is recommended for cisgender men who have sex with men and transgender women, regardless of HIV status. 1 Dosing should occur no more frequently than daily. 1

Post-Exposure Prophylaxis

PEP is recommended for all persons who have sustained a mucosal or parenteral exposure to HIV from a known infected source and should be initiated as soon as possible. 1 PEP interventions are associated with protective effects estimated at 81%. 3

Implementation Priorities

A serostatus-neutral approach should be adopted to reduce stigma, ensuring that people diagnosed with HIV are rapidly linked to care while those who test negative are informed about and navigated to PrEP services if desired or indicated. 1

The optimal prevention strategy for any individual is the one most acceptable and congruent with their routes of potential HIV exposure, preference for modality of administration, and ability to adhere to the regimen. 1 Regular risk reassessment should guide ongoing prevention needs. 1

Common Pitfalls to Avoid

Do not wait for specific behavioral criteria before offering PrEP—it should be discussed with all sexually active persons and anyone requesting it. 1 Do not rely solely on rapid HIV antibody testing before PrEP initiation, as this can miss acute infection; include RNA testing when available. 1 Do not implement behavioral interventions in isolation from biomedical approaches—combination strategies are essential for maximum effectiveness. 1, 2