From the Guidelines
HIV transmission can be prevented by using condoms consistently during sex, avoiding sharing needles, and adhering to antiretroviral therapy (ART) which can reduce viral load to undetectable levels, making transmission virtually impossible. The main transmission routes are unprotected sexual contact, sharing needles or syringes, mother-to-child transmission during pregnancy, childbirth, or breastfeeding, and through transfusions of contaminated blood products (though this is now rare in countries with proper screening) 1.
Transmission Routes
- Unprotected sexual contact: The risk of infection by male-to-male receptive anal intercourse has been estimated to be between 1 in 10 and 1 in 1600, by male-to-female vaginal intercourse has been estimated to be 1 in 200 to 1 in 2000, and by female-to-male vaginal intercourse has been estimated to be between 1 in 700 and 1 in 3000 1.
- Sharing needles or syringes: The risk of infection by needle sharing has been estimated to be 1 in 150 1.
- Mother-to-child transmission: Perinatal transmission can occur during pregnancy (intrauterine), during labor and delivery (intrapartum), or after delivery through breast-feeding (postpartum) 1.
- Transfusions of contaminated blood products: The overall probability of becoming infected by transfusion with contaminated blood or blood products has been estimated to be 95 in 100 1.
Prevention Methods
- Using condoms consistently during sex can prevent HIV transmission 1.
- Adhering to antiretroviral therapy (ART) can reduce viral load to undetectable levels, making transmission virtually impossible (known as U=U, or Undetectable equals Untransmittable) 1.
- Pre-exposure prophylaxis (PrEP) medications like Truvada or Descovy (taken daily) can prevent HIV acquisition in HIV-negative individuals at high risk.
- Post-exposure prophylaxis (PEP) can be used within 72 hours after potential exposure and must be taken for 28 days. HIV cannot spread through casual contact like hugging, sharing food, or using the same toilet 1. The virus cannot survive long outside the body and is relatively fragile in the environment, requiring direct fluid exchange for transmission.
From the Research
HIV Transmission and Prevention
- HIV transmission can be prevented through the use of antiretroviral pre-exposure prophylaxis (PrEP) 2, 3, 4, 5.
- PrEP has been shown to be highly efficacious in preventing HIV acquisition in people at risk, with daily oral emtricitabine (FTC)-tenofovir disoproxil fumarate (TDF) being a commonly used regimen 2, 4, 5.
- The efficacy of PrEP is highly correlated with adherence, with studies showing that daily TDF/emtricitabine can reduce HIV acquisition by over 90% 2.
- PrEP is safe and well-tolerated, with minimal impact on kidney, bone, or pregnancy outcomes, and no evidence of risk compensation 2, 5.
Barriers to PrEP Uptake
- Despite the effectiveness of PrEP, its uptake is lagging, particularly among populations with disproportionate HIV burden 6.
- Barriers to PrEP usage include knowledge/awareness of PrEP, perception of HIV risk, stigma from healthcare providers or family/partners/friends, distrust of healthcare providers/systems, access to PrEP, costs of PrEP, and concerns around PrEP side effects/medication interactions 6.
- These barriers may have different effects on specific populations at risk, and strategies to address them should include educational interventions, innovative approaches to delivery of HIV care, financial support, and destigmatization of PrEP and PrEP users 6.
Current Research and Trends
- Recent studies have explored the use of different antiretroviral agents in PrEP, including maraviroc, rilpivirine, and cabotegravir 3.
- The optimal combination prevention program needs to be defined, and this will depend on local epidemiology, service provision, and cost effectiveness 5.
- Further research is needed to address the challenges and limitations of PrEP, including access, adherence, and risk compensation 2, 3, 4, 5, 6.