Globally, the human immunodeficiency virus (HIV) continues to be a public health problem that harms and, in the worst cases, claims the lives of many people. According to the World Health Organization, an estimated 38 million people worldwide are living with HIV. In 2019, approximately 700,000 people died and there were 1.7 million new HIV infections. In the United States and its territories, there are 1.2 million people with HIV, and in 2018, approximately 38,000 new cases were diagnosed. Faced with the current challenges in developing a cure and the limited effectiveness of the traditional approach to preventing HIV, other methods of prevention for this pandemic have been developed. Post-exposure prophylaxis (PEP) and pre-exposure prophylaxis (PrEP) are two examples of the clinical preventive approach.
Post-exposure prophylaxis post-exposure prophylaxis (PEP) is based on the use of antiretroviral drugs for 28 consecutive days. Therapy should be started within 72 hours of possible exposure to HIV. Protocols recommend the combination of emtricitabine/tenofovir together with an integrase inhibitor such as dolutegravir or raltegravir.
Transition
Pre-exposure prophylaxis pre-exposure prophylaxis (PrEP) is daily, continuous treatment with antiretroviral drugs for people whose behaviors put them at risk of acquiring HIV. The medications approved by the FDA for PrEP are the combination emtricitabine/tenofovir (Truvada® or Descovy®, 1 tablet/day). These are effective for HIV prevention if used correctly. In addition, emphasis should be placed on behavior modification to reduce the possibility of infection.
Some patients who have received PEP continue to be exposed to HIV through behaviors such as not using protective barriers or problematic substance use. Thus, patients who have received multiple PEP treatments in a relatively short period of time can be advised that a good HIV prevention strategy would be to transition to PrEP. The 2017 USPHS (U.S. Public Health Service) Clinical Guidelines for HIV PrEP propose two alternatives for this transition, which we summarize below:
Immediate transition
Experts recommend starting PrEP early if exposure to HIV remains latent in a patient receiving PEP, especially when there are high-risk behaviors. In such cases, the patient should show interest in starting this treatment after medical counseling. This will reduce the chances of future exposure. After completing 28 days of PEP, it is recommended that a rapid HIV test or, ideally, a 4th generation HIV antigen/antibody test be performed. We must evaluate all possible signs and symptoms associated with acute HIV infection and complete laboratory tests (renal, metabolic, and hepatic function), among other studies. The patient will receive guidance on treatment adherence and the use of protective barriers.
Delayed initiation of PrEP (post-exposure prophylaxis)
This may occur due to patient preference or the desire to have a negative HIV result after exposure that led to taking PEP. It may also occur if there are delays or administrative conflicts in obtaining the drug. There are currently multiple research protocols to evaluate different drugs to prevent HIV, to evaluate more oral antiretrovirals, topical creams, and research on long-acting injectables such as cabotegravir (to prevent or treat HIV).
Comment
Antiretroviral prophylaxis represents an important step in integrated efforts to halt the HIV pandemic. There is strong scientific evidence confirming that transitioning from PEP to PrEP in patients with ongoing high-risk exposure would have substantial benefits in preventing new infections. These efforts represent a major incentive to achieve the UN's goal of ending HIV by 2030.
Originally published in Galenus Magazine.
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