What is the role of PrEP & PEP in HIV prevention

Understanding the role of PrEP & PEP in HIV prevention

HIV (Human Immunodeficiency Virus) continues to be a significant global health issue. Despite advances in treatment and prevention, the virus still poses a serious threat to millions of people worldwide. Two critical tools in the fight against HIV are PrEP (Pre-Exposure Prophylaxis) and PEP (Post-Exposure Prophylaxis). 

Both are preventive measures aimed at reducing the risk of HIV transmission, but they are used in different circumstances and work through distinct mechanisms. In this article, we’ll explore what PrEP and PEP are, how they work, their processes, and their importance in HIV prevention.

What is PrEP?

PrEP (Pre-Exposure Prophylaxis) is a daily medication taken by individuals who do not have HIV but are at high risk of contracting the virus. PrEP is designed to prevent HIV infection by creating a protective barrier within the body before exposure to the virus occurs. It is highly effective when taken consistently and correctly.

PrEP involves the use of a combination of two antiretroviral medications—tenofovir and emtricitabine—which are sold under the brand name Truvada. A newer formulation called Descovy is also available for PrEP but is not approved for use by individuals at risk through vaginal sex.

How Does PrEP Work?

PrEP works by preventing HIV from replicating and establishing itself in the body after exposure. If someone who is on PrEP comes into contact with HIV through sexual activity or injection drug use, the medication works by blocking an enzyme called reverse transcriptase, which the virus needs to multiply. Without the ability to replicate, the virus cannot spread throughout the body, thereby preventing infection.

Who Should Use PrEP?

PrEP is recommended for individuals who are at high risk of HIV exposure, including:

• People with HIV-positive partners: Especially if their partner has not achieved viral suppression through treatment.
• Men who have sex with men (MSM): Particularly those who engage in unprotected anal sex.
• Heterosexual men and women: If they have an HIV-positive partner, multiple sexual partners, or engage in unprotected sex.
• Injection drug users: Especially if they share needles or other injection equipment.
• Sex workers: Due to increased risk of exposure through frequent sexual encounters.
• Individuals who engage in transactional sex: Those who may exchange sex for money, drugs, or housing.

How to Use PrEP

PrEP is taken daily, and adherence is crucial for its effectiveness. Studies show that when taken consistently, PrEP reduces the risk of HIV infection through sex by more than 99% and by 74% among people who inject drugs. Missing doses can reduce its effectiveness, which is why it’s vital to stick to a daily regimen.

Before starting PrEP, an individual must test negative for HIV and undergo regular testing while using PrEP to ensure they remain HIV-negative. Additionally, individuals on PrEP should be monitored for side effects and kidney function, as the medication can cause kidney issues in rare cases.

Benefits of PrEP

• Highly Effective: When used correctly, PrEP offers near-total protection from HIV.
• Empowers Users: PrEP provides a proactive way for people to protect themselves from HIV.
• Well Tolerated: Most people experience few or no side effects.
• Reduces Anxiety: People at high risk of HIV often experience anxiety about contracting the virus. PrEP can help alleviate this worry.

Challenges of PrEP

• Adherence: The effectiveness of PrEP depends on consistent daily use. Missing doses can reduce its protective benefits.
• Access: PrEP may be expensive or difficult to access in some areas, particularly in low-resource settings.
• Does Not Protect Against STIs: PrEP only prevents HIV, so other methods, like condoms, are still necessary to prevent sexually transmitted infections (STIs).

What is PEP?

PEP (Post-Exposure Prophylaxis) is an emergency medication regimen designed to prevent HIV after possible exposure. Unlike PrEP, which is taken on an ongoing basis to prevent infection before exposure, PEP is used after potential exposure to HIV. PEP must be started within 72 hours of the exposure, and the sooner it is initiated, the better the chances of preventing HIV.

PEP is typically a 28-day course of antiretroviral therapy (ART), which consists of a combination of drugs used to treat HIV-positive individuals. These drugs prevent the virus from multiplying in the body, giving the immune system a chance to clear the infection before it becomes permanent.

How Does PEP Work?

PEP works by using antiretroviral medications to block HIV replication after the virus has entered the body. If HIV cannot replicate effectively, it cannot establish a permanent infection. The PEP regimen typically involves taking three medications from two different drug classes to maximize the effectiveness of treatment.

Who Should Use PEP?

PEP is intended for individuals who have had a potential exposure to HIV. Some common scenarios where PEP might be used include:

• Unprotected sex: If a condom breaks or if sex occurs without a condom with someone who is HIV-positive or whose status is unknown.
• Sexual assault: PEP is often prescribed to survivors of sexual assault who may have been exposed to HIV.
• Needle-sharing: Individuals who share needles or other drug injection equipment with someone who is HIV-positive or whose status is unknown.
• Occupational exposure: Healthcare workers or others who may come into contact with HIV-infected blood or fluids through needlestick injuries or similar accidents.

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How to Use PEP

PEP must be started as soon as possible, ideally within 2 hours after exposure, and definitely within 72 hours. Delaying treatment reduces its effectiveness. Once started, PEP must be taken every day for 28 days. Completing the full course of treatment is crucial to ensuring that HIV does not establish itself in the body.

After completing the PEP regimen, individuals should undergo follow-up HIV testing to confirm that the virus has not been transmitted.

Benefits of PEP

Emergency Prevention: PEP provides a critical line of defence after accidental or unexpected exposure to HIV.

Highly Effective: When started promptly and taken as prescribed, PEP significantly reduces the risk of HIV transmission.

Access in Emergencies: Many healthcare providers and emergency departments have protocols in place to provide PEP quickly to those in need.

Challenges of PEP

• Time-Sensitive: PEP must be started within a strict time window (72 hours), which may not always be possible depending on the circumstances.
• Adherence: Like PrEP, PEP requires strict adherence to the daily medication regimen for the full 28 days to be effective.
• Side Effects: Some individuals may experience side effects from PEP, such as nausea, fatigue, or headaches, which can make it challenging to complete the regimen.
• Not a Regular Prevention Tool: PEP is not intended for ongoing prevention; individuals who are at continuous risk for HIV should consider PrEP instead.

Importance of PrEP and PEP in HIV Prevention

Both PrEP and PEP are essential tools in the global fight against HIV. By offering ways to prevent HIV transmission, they empower individuals to take control of their health and reduce their risk of contracting the virus.

PrEP’s Importance

Long-Term Protection: PrEP offers sustained protection for people at high risk of HIV exposure, especially for those in serodiscordant relationships (where one partner is HIV-positive and the other is not).

Empowerment: PrEP gives individuals the ability to protect themselves from HIV without relying solely on their partner’s actions or condom use.

Reducing New Infections: Widespread use of PrEP has the potential to dramatically reduce new HIV infections, especially in high-risk communities.

PEP’s Importance

Emergency Response: PEP is a life-saving intervention in emergency situations, providing a crucial safety net after accidental or unexpected exposure to HIV.

Post-Exposure Protection: PEP ensures that those who may have been exposed to HIV have a chance to prevent infection from taking hold, particularly in high-risk situations like sexual assault or needlestick injuries.

Conclusion

PrEP and PEP are vital components of HIV prevention strategies. PrEP serves as a long-term protective measure for individuals at ongoing risk of HIV, while PEP provides emergency protection after potential exposure.

Both approaches empower individuals to take charge of their health, helping to reduce the global burden of HIV. However, adherence, education, and access are key to maximizing their effectiveness, and ongoing efforts are needed to ensure that these life-saving tools are available to those who need them most.

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