Post-exposure prophylaxis (PEP) is a crucial preventive treatment that can significantly reduce the risk of acquiring certain infections after potential exposure.
Whether from occupational hazards, sexual encounters, or other situations, PEP offers an essential line of defence against diseases such as HIV and hepatitis.
In this post, we will explore what PEP is, its significance, how it works, and who may benefit from it.
Post-exposure prophylaxis (PEP)
Post-exposure prophylaxis (PEP) is a short-term course of antiretroviral medications or other preventive therapies administered to individuals who have been exposed to an infectious agent but have not yet developed symptoms.
PEP is most commonly used to prevent HIV infection after potential exposure, but it can also be used for other bloodborne pathogens such as hepatitis B and C.
Additionally, PEP should be used in conjunction with other HIV prevention strategies, such as condom use and harm reduction practices, to reduce the risk of HIV transmission.
How does PEP work?
PEP works by preventing the replication of the virus or pathogen in the body, thereby reducing the likelihood of establishing infection.
The effectiveness of PEP depends on several factors, including the timing of initiation, the duration of treatment, and adherence to the prescribed regimen.
- Timing: PEP should ideally be initiated as soon as possible after exposure, preferably within hours but no later than 72 hours (3 days) after exposure. The earlier PEP is started, the greater the likelihood of preventing infection.
- Duration: PEP typically involves taking antiretroviral medications or other preventive therapies for 28 days. It’s essential to complete the full course of treatment as prescribed to maximise effectiveness.
- Adherence: Adherence to the prescribed PEP regimen is critical for its effectiveness. Missing doses or discontinuing treatment prematurely can reduce the efficacy of PEP and increase the risk of infection.
Types of PEP
- Occupational PEP (oPEP): Occupational PEP is administered to healthcare workers and other individuals who have been exposed to HIV through occupational exposures, such as needlestick injuries, mucous membrane exposure to blood or other body fluids, or contact with HIV-infected blood or bodily fluids. Occupational PEP is typically initiated as soon as possible after the exposure, ideally within hours, and consists of a 28-day course of antiretroviral medications.
- Non-occupational PEP (nPEP): Non-occupational PEP is administered to individuals who have been exposed to HIV outside of occupational settings, such as through sexual assault, unprotected sexual intercourse, or injection drug use with shared needles or syringes. Non-occupational PEP is initiated within 72 hours (ideally within 36 hours) of the potential exposure and consists of a 28-day course of antiretroviral medications.
Both types of PEP involve the use of a combination of antiretroviral drugs, typically including two nucleoside reverse transcriptase inhibitors (NRTIs) plus a third drug from another class, such as a protease inhibitor (PI), a non-nucleoside reverse transcriptase inhibitor (NNRTI), or an integrase strand transfer inhibitor (INSTI).
The specific medications and dosages used for PEP may vary depending on factors such as the type of exposure, the HIV status of the source individual (if known), and the individual’s medical history and risk factors.
Timing of initiation
Timely access to PEP is crucial for its effectiveness in preventing HIV infection after potential exposure.
PEP should be initiated as soon as possible after exposure, ideally within 72 hours, and continued for a 28-day course of treatment.
Delaying the initiation of PEP beyond 72 hours reduces its effectiveness and may increase the risk of HIV transmission.
Therefore, individuals who believe they have been exposed to HIV should seek medical care promptly to assess their eligibility for PEP and initiate treatment if indicated.
Duration of treatment
The duration of PEP treatment typically lasts for 28 days (4 weeks).
It is important to complete the full course of PEP as prescribed, even if there are no immediate side effects or symptoms of HIV infection.
Prematurely discontinuing PEP can reduce its effectiveness and increase the risk of HIV transmission.
Antiretroviral medications
PEP regimens typically consist of a combination of three antiretroviral drugs from different classes to maximise effectiveness and reduce the risk of drug resistance.
Commonly used antiretroviral medications for PEP may include:
- Tenofovir disoproxil fumarate (TDF)
- Emtricitabine (FTC)
- Raltegravir (RAL)
- Dolutegravir (DTG)
- Lamivudine (3TC)
- Zidovudine (ZDV)
The specific antiretroviral drugs and dosages prescribed for PEP may vary based on factors such as local guidelines, drug availability, individual health considerations, and potential drug interactions.
Dosage and administration
The dosage and administration of antiretroviral medications for PEP may vary depending on the specific drugs prescribed.
Healthcare providers will provide detailed instructions on how to take PEP medications, including dosages, frequency, and any special considerations.
- Oral medications: Most PEP regimens involve taking oral tablets or pills once or twice daily. The exact dosage and frequency of administration will depend on the specific antiretroviral drugs prescribed. It is essential to take PEP medications exactly as prescribed, at the same time each day, with or without food, as instructed by healthcare providers.
- Injectable medications: In some cases, PEP may involve the administration of injectable antiretroviral medications, such as raltegravir or zidovudine, in addition to oral medications. Injectable PEP may be recommended in situations where oral medications are not feasible or in cases of severe exposure.
Benefits of PEP
- Prevents HIV transmission: PEP reduces the risk of HIV infection after potential exposure to the virus.
- Reduces Anxiety: Provides peace of mind and reassurance to individuals who have been exposed to HIV.
- Protects Health: Minimises the risk of developing HIV-related complications and progression to AIDS.
- Minimal Side Effects: Generally well-tolerated, with few reported side effects.
- Opportunity for counselling: Offers an opportunity for risk reduction counselling and education on safer sex practices.
- Prevents Spread: Helps prevent further transmission of HIV to sexual partners or others.
Differences between PrEP and PEP
Pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) are two HIV prevention strategies.
Essentially, while PrEP provides continuous protection for individuals at an ongoing high risk of HIV exposure, PEP offers short-term protection following a specific exposure event.
This table provides an overview of the main differences between PrEP and PEP, focusing on aspects such as timing of administration, purpose, duration of use, effectiveness, accessibility, and target population.
| ASPECT | PRE-EXPOSURE PROPHYLAXIS (PrEP) | POST-EXPOSURE PROPHYLAXIS (PEP) |
|---|---|---|
| Timing of Administration | Taken regularly before potential exposure to HIV | Taken within 72 hours after potential exposure to HIV |
| Purpose | Prevents HIV infection before exposure | Reduces risk of HIV infection after exposure |
| Duration of Use | Taken on an ongoing basis for as long as risk persists | Taken for a 28-day course following a specific exposure event |
| Effectiveness | Highly effective when taken consistently and correctly | Highly effective when initiated promptly after exposure |
| Accessibility | Available by prescription, it requires regular monitoring | Accessible at healthcare facilities, emergency departments |
| Target Population | Individuals are at ongoing high risk of HIV exposure | Individuals with recent high-risk exposure to HIV |
People who can benefit from PEP
Several populations are at increased risk of HIV exposure due to various factors, including sexual behaviours, injection drug use, occupational hazards, and sexual assault.
These populations may benefit from PEP if they experience a potential exposure to HIV, such as unprotected sexual intercourse with an HIV-positive partner, sharing needles or injection equipment with someone who has HIV, occupational exposure to HIV-infected blood or bodily fluids, or sexual assault by an HIV-positive perpetrator.
1. High-risk sexual behaviours
People who engage in high-risk sexual behaviours, such as condomless anal or vaginal intercourse with multiple partners, commercial sex work, or sex with partners of unknown HIV status, are at increased risk of HIV exposure.
These individuals may benefit from PEP if they experience a potential exposure to HIV, such as a condom break during intercourse or sexual assault.
2. People who inject drugs
Injection drug users are at heightened risk of HIV transmission due to the sharing of needles or injection equipment contaminated with HIV-infected blood.
Individuals who inject drugs may benefit from PEP if they experience a potential exposure to HIV, such as sharing needles or injection equipment with someone who has HIV or experiencing an accidental needlestick injury.
3. Healthcare workers and first responders
Healthcare workers, emergency responders, and other first responders are at risk of occupational exposure to HIV-infected blood or bodily fluids through needlestick injuries, splashes, or other accidents.
These individuals may benefit from PEP if they experience a potential exposure to HIV in the workplace, such as a needlestick injury while administering medical care to an HIV-positive patient.
4. Sexual assault survivors
Survivors of sexual assault are at increased risk of HIV transmission if the perpetrator is HIV-positive.
Individuals who have experienced sexual assault may benefit from PEP if they have been exposed to HIV during the assault and seek medical care promptly for assessment and treatment.
Steps in PEP
1. Recognise the risk
If you believe you have been exposed to HIV through unprotected sexual intercourse, needlestick injuries, or other high-risk activities, it is important to recognise the potential risk and seek medical attention promptly.
Time is critical in initiating PEP, so do not delay in seeking help.
2. Seek medical evaluation
Immediately after a potential exposure to HIV, contact a healthcare provider or visit an emergency department for a thorough medical evaluation.
Inform the healthcare provider about the nature of the exposure, including the type of contact and the circumstances surrounding the incident.
3. Assessment for PEP eligibility
The healthcare provider will assess your risk factors, medical history, and the timing of the exposure to determine if you are eligible for PEP.
PEP is typically recommended for individuals who have had a recent high-risk exposure to HIV within the past 72 hours (3 days).
4. Counselling and informed consent
Before initiating PEP, the healthcare provider will provide counselling and information about the potential benefits and risks of PEP, as well as the importance of adhering to the medication regimen.
You will be asked to provide informed consent before starting PEP.
5. Prescribing PEP medications
If deemed eligible for PEP, the healthcare provider will prescribe a combination of antiretroviral medications, usually taken orally for 28 days.
The most commonly prescribed PEP regimen consists of two nucleoside reverse transcriptase inhibitors (NRTIs) combined with a third antiretroviral drug, typically a protease inhibitor or an integrase strand transfer inhibitor.
6. Initiation of PEP
Begin taking the prescribed PEP medications as soon as possible after the exposure, ideally within the first 72 hours (3 days) but no later than 72 hours post-exposure.
Follow the healthcare provider’s instructions for dosing and timing of medication administration.
7. Follow-up care
Throughout PEP, attend follow-up appointments with your healthcare provider for monitoring, assessment of medication side effects, and support.
Be sure to adhere to the prescribed medication regimen and report any adverse reactions or concerns to your healthcare provider promptly.
8. HIV testing
While on PEP, it is important to undergo HIV testing at baseline (before starting PEP), at regular intervals during treatment, and after completing the full course of PEP.
HIV testing is essential for the early detection of infection and to determine the effectiveness of PEP in preventing HIV transmission.
9. Completion of PEP
Complete the full 28-day course of PEP as prescribed by your healthcare provider, even if you experience no symptoms or side effects.
Do not discontinue PEP prematurely, as this may reduce its effectiveness in preventing HIV infection.
10. Risk reduction counselling
After completing PEP, continue to prioritise safer sex practices, condom use, and harm reduction strategies to reduce the risk of future HIV exposure.
Consider discussing HIV prevention options, such as pre-exposure prophylaxis (PrEP), with your healthcare provider if you are at ongoing risk of HIV infection.
Frequently asked questions
1. What is PEP?
PEP stands for post-exposure prophylaxis.
It is a preventive treatment for HIV that is taken after potential exposure to the virus to reduce the risk of infection.
2. When should I consider taking PEP?
PEP is recommended for individuals who have had recent possible exposure to HIV, such as unprotected sex with someone known to be HIV-positive, sharing needles or injection equipment with someone who has HIV, or experiencing a needle stick injury or other occupational exposure to HIV-infected blood or body fluids.
3. How soon after exposure should PEP be started?
PEP should be initiated as soon as possible after exposure to HIV, ideally within 72 hours (3 days), but no later than 72 hours after exposure.
The sooner PEP is started, the more effective it is likely to be in preventing HIV infection.
4. How long do I need to take PEP?
The standard course of PEP typically lasts for 28 days (4 weeks).
It is essential to complete the full course of PEP as prescribed by a healthcare provider, even if you experience no side effects or symptoms during treatment.
5. How effective is PEP in preventing HIV infection?
PEP is highly effective when taken as prescribed and initiated promptly after exposure to HIV.
However, its effectiveness depends on factors such as the timing of initiation, the type of exposure, and adherence to the medication regimen.
PEP is not 100% effective and should not be relied upon as the sole HIV prevention method.
6. What are the side effects of PEP?
Common side effects of PEP may include nausea, diarrhoea, headaches, fatigue, and dizziness.
These side effects are usually mild and temporary, but some individuals may experience more severe reactions.
It is essential to discuss any concerns or side effects with a healthcare provider.
7. How do I get PEP?
PEP is available by prescription and can be obtained from healthcare providers, emergency departments, or specialised HIV clinics.
If you believe you have been exposed to HIV and may benefit from PEP, seek medical attention immediately to discuss your options and receive timely treatment.
8. Is PEP the same as PrEP?
No, PEP (post-exposure prophylaxis) is different from PrEP (pre-exposure prophylaxis).
PEP is taken after a potential exposure to HIV to prevent infection, while PrEP is taken before a potential exposure to reduce the risk of HIV infection.
Both PEP and PrEP are essential components of HIV prevention strategies, but they serve different purposes.
9. Does PEP protect against other sexually transmitted infections (STIs)?
No, PEP only provides protection against HIV and does not protect against other STIs.
Individuals using PEP should continue to practice safer sex and other preventive measures to reduce the risk of STIs and other infections.
10. Is PEP covered by insurance?
PEP may be covered by insurance, but coverage may vary depending on the type of insurance plan and provider.
Some healthcare facilities may offer assistance programmes or resources to help individuals access PEP if cost is a barrier.
It is advisable to check with your insurance provider or healthcare facility to determine coverage and eligibility for PEP.
Obisesan Damola
Damola is a medical doctor who has worked in the Nigerian healthcare industry for a little over 3 years in a number of primary, secondary, and tertiary hospitals. He is interested in and writes about how technology is helping to shape the healthcare industry. He graduated from the College of Medicine, University of Ibadan, the foremost medical training institution in Nigeria.
