HIV PEP: Post-Exposure Prophylaxis for HIV

What is the Emergency HIV PEP ?

HIV Post Exposure Prophylaxis, or PEP, is a medical intervention designed to prevent HIV infection after a person has been potentially exposed to the virus. This critical prevention strategy involves a regimen of antiretroviral drugs taken within 72 hours of exposure, ideally within 4 hours and preferably within 24-48 hours.

How does HIV PEP work?

PEP works by interfering with the virus’s ability to replicate within the body’s cells. According to guidelines from the CDC, the International Antiviral Society-USA, and the European AIDS Clinical Society, the standard course lasts for 28 days. This duration is critical to ensure the medication has enough time to effectively combat any HIV virus that may have entered the body.

How Does PEP Fit into HIV Prevention Strategies?

Incorporating PEP into HIV prevention strategies offers a second chance at prevention for those who have had a recent high-risk exposure to HIV. It is an essential component of comprehensive HIV prevention, alongside other methods such as Pre-Exposure Prophylaxis (PrEP) for those at ongoing risk, condom use, and regular HIV testing. While PEP is highly effective, it is not a substitute for these other prevention methods but rather a critical safety net in emergency situations.

When to Consider HIV PEP

In the journey of HIV prevention, understanding the right moment to consider Post Exposure Prophylaxis (PEP) is crucial. PEP serves as an emergency intervention. It also actห as a powerful shield against HIV infection when taken within the critical window after potential exposure. But knowing exactly when to seek out PEP is essential for its effectiveness.

Who should get HIV PEP ?

High-risk exposures to HIV include situations where an individual has had unprotected sexual contact, including vaginal or anal intercourse, with a person known to have HIV or whose HIV status is unknown but could be at risk. Other scenarios include:

• Unprotected receptive oral sex with someone at risk of HIV.
• Sharing needles, syringes, or other equipment to inject drugs.
• Experiencing accidents where a condom broke or slipped during intercourse.
• Expose to HIV through occupational hazards, such as needlestick injuries.
• Expose to mucous membranes, blood, or bodily fluids, unsure to be source of HIV virus.

When should you start HIV PEP ?

The efficacy of PEP diminishes over time post-exposure, making the 72-hour window following a potential HIV exposure critical. The Centers for Disease Control and Prevention (CDC) underscores the importance of initiating PEP as soon as possible, ideally within 24 hours. The sooner, the better the chance of preventing HIV infection. Consider the nature of the exposure and the HIV status of any involved partner. When in doubt, seeking immediate medical advice can help determine if PEP is the right course of action.

What is the Effectiveness of HIV PEP

The effectiveness of PEP in preventing HIV infection is significant when started within 72 hours of exposure and taken consistently for 28 days. It can be estimated about 70-80%.  Studies “Updated Guidelines for the Use of Post-Exposure Prophylaxis After Sexual, Injection Drug Use, or Other Nonoccupational Exposure to HIV—United States, 2016” have shown that the medication can significantly reduce the risk of HIV infection if the regimen is adhered to fully. A landmark study for the effectiveness of PEP is the Brussels Needlestick Study, which found a substantial reduction in HIV transmission among healthcare workers who received PEP after occupational exposure. 

What Causes HIV PEP Failure?

HIV Post-Exposure Prophylaxis (PEP) can be a crucial intervention for preventing HIV infection after potential exposure. However, its effectiveness can be compromised by various factors. Understanding these causes is essential to ensuring the best possible outcomes when using PEP.

Common Causes of HIV PEP Failure

• False Positive HIV Test Before PEP Course: If the initial HIV test is a false positive, PEP may be ineffective from the start.
• Lack of HIV Testing Before Starting PEP: Obtaining PEP medication from unauthorized sources, such as the black market, pharmacies, or unethical online clinics, without proper HIV testing can lead to failure.
• Delayed Start of PEP: PEP is most effective when started within 72 hours of exposure. Delaying beyond this window significantly reduces its efficacy.
• Inconsistent PEP Usage: Skipping doses or not taking PEP daily can lead to insufficient drug levels in the body, reducing its effectiveness.
• Premature Discontinuation: Stopping PEP before completing the full 28-day course can result in incomplete protection.
• Drug-Resistant HIV: Infection with a strain of HIV that is resistant to the medications used in PEP can lead to treatment failure.

What are Side Effects of HIV PEP ?

While PEP (Post-Exposure Prophylaxis) is generally safe, there are potential side effects that can vary depending on the specific medication regimen. It’s important to be aware of these possible side effects and consult with healthcare providers throughout the course of PEP to manage any adverse effects.

the Common Side Effects of HIV PEP?

• Nausea and Vomiting: The most frequently reported side effects and can occur soon after starting PEP.
• Diarrhea: Many individuals experience gastrointestinal disturbances, including diarrhea, which can vary in severity.
• Fatigue: Feeling unusually tired or weak is a common side effect that can affect daily activities.
• Headache: Some people may experience persistent or intermittent headaches during the treatment.
• Dizziness: Dizziness or lightheadedness can also occur, impacting balance and overall comfort.

the Severe Side Effect of HIV PEP?

• Liver Toxicity: In rare cases, PEP medications can cause liver damage, necessitating regular monitoring of liver function.
• Kidney Toxicity: Kidney function can also be affected, requiring periodic blood tests to ensure proper renal health.
• Allergic Reactions: Although uncommon, allergic reactions to PEP medications can occur and may require immediate medical attention.

What Tests are Needed Before Starting HIV PEP ? 

Before initiating Emergency PEP, certain baseline tests are recommended to assess the individual’s suitability for the medication and to rule out any existing infections. These typically include:

• HIV Test: An initial test to confirm the individual’s HIV status before starting PEP. Consider other treatment options if the test shows a positive result.
• Hepatitis B Test: Since PEP medications can also suppress hepatitis B virus. Testing is important before starting the medication.
• Hepatitis C Test: The current Hepatitis C infection could result in False negative of HIV tests due to delayed antibody response.
• Kidney and Liver Function Tests: The antiretrovirals can affect liver and kidney function if you have current kidney and liver condition.
• Pregnancy Test: For women of childbearing age, to ensure that PEP medication choices are safe in case of pregnancy.

What is Follow-up Testing of HIV PEP ?

Tests to do while taking HIV PEP

• Syphilis test: Syphilis infection may develop early at 3 weeks from Exposure. The common symptoms are rash and genital ulcer or oral ulcer.
• PCR multiplex: Location specific STD infection may happen as the earliest as 5-7 days after exposure such as Gonorrhrea, Chlamydia, Mycoplasma, Herpes.

Tests to do after finishing HIV PEP

• HIV Test: Conducted at several intervals, such as after 4-6 weeks, 3 months, for the 99.8% + accuracy.
• Other STDs test: Having been at risk of HIV is also in risk of other STDs, and it is asymptomatic. Ensure to check for other systemic STD like Syphilis, Hepatitis.
• PCR multiplex: Location specific STD infection can happen without showing symptoms. Screening after finishing PEP is also recommended.
• Kidney and Liver Function Tests: To monitor any potential side effects from the medication on liver and kidney health, if indicated.
  
  Remark: After having experienced sexual risk events, there’s a chance it could happen again. HIV PrEP (Pre-Exposure Prophylaxis) could prevent you from taking medication for the whole 28 days, and it has very high efficacy (86-99%).