Exposure to HIV is an emergency.
If you think you have had a risk, seek help immediately. Every hour that passes increases the potential for infection.
This post will answer patient FAQs about PEP treatment guidelines.
1. What does PEP mean?
PEP stands for post-exposure prophylaxis.
What is prophylaxis? The definition of prophylaxis is the prevention of disease.
PEP refers specifically to HIV post-exposure prophylaxis.
STOP HIV AFTER EXPOSURE.
PEP treatment guidelines
2. Who should take PEP?
PEP is for emergencies when possible exposure to HIV occurs.
This means direct contact with possible HIV-infected liquids: semen, vaginal fluids, or blood.
Risk situations include
- Condom-breakage
- Unprotected sex
- Shared needles
- Sexual assault
Patients who are HIV-negative or do not know their status can enquire about taking PEP. Your doctor will always check your baseline HIV status at your PEP consultation.
PEP is not indicated for 1,2
- Kissing
- Spitting
- Oral-to-oral contact with no bleeding, e.g., CPR
- Sharing of sexual toys
What about bites?
A bite is not considered a risk exposure to either party when the integrity of the skin is not disrupted.
Scenarios where bites may result in blood exposure:
Blood exposure to the biter: When the biter inflicts a wound that breaks the skin and blood from the bitten individual enters the biter’s mouth.
Blood exposure to the bitten individual: When the biter has blood in his or her mouth (e.g., from bleeding gums or lesions) and inflicts a wound that breaks the skin of the individual bitten.
Blood exposure to both parties: A break in the skin of the individual who was bitten and the biter has blood in his/her mouth (e.g., from bleeding gums or lesions). 1,2
3. What medication is PEP?
The drugs in PEP are ARVs. ARV stands for antiretrovirals. These are medications that treat and prevent HIV infection.
ARVs have come a long way in the past 20 years.
“In 2001, while performing a caesarian section, I had a high-risk exposure to HIV. The PEP 20 years ago involved many tablets with many side effects.”
In 2024, we use newer generation ARVs with minimal side effects.
A combination of 3 ARVs is in PEP.
This might be
- A single tablet containing all 3 ARVs once daily.
- A twice-a-day dosing regime.
Your doctor will decide what is appropriate for you. They will ask about your
- medical history and
- current medication.
One pill daily is ideal. Patients are more likely to complete the 28-day course because it is easy to remember to take.
4. When should I start PEP?
Exposure to HIV is an emergency.
Every minute counts. The sooner, the better. The idea is that you want to stop HIV from infecting and replicating.
PEP should be initiated immediately—ideally within 2 hours of an exposure but no later than 72 hours after an exposure—because the effectiveness of PEP decreases over time after 2 hours. 1,2
Let me explain why this is on a timeline.
| TIME FROM EXPOSURE | |
|---|---|
| 2 hours | HIV breaks through the skin or mucous membrane |
| 2 to 4 hours | Your immune system responds in the area. HIV replicates in macrophages and dendritic cells |
| 48 to 72 hours | HIV has made it to the local lymph nodes |
| > 72 hours | HIV is in your bloodstream |
After 72 hours, PEP must not be used. The virus is already in the bloodstream after 3 to 5 days from exposure.
Taking ARVs after three days and then stopping after a month can lead to complications:
- Viral load rebound
- HIV resistance to ARVs
5. What tests will I need when starting PEP?
Your doctor might do a rapid HIV test in the rooms. They will also send blood to the laboratory for a more sensitive HIV test, a 4th-generation HIV Ag/Ab combination test.
They will also do baseline tests for hepatitis B, kidney, and liver functions. Other tests might be necessary for your particular medical history.
6. When should I test again for HIV?
Although seroconversion is rare, it is important to remember that PEP is not 100% effective.
The recommendations are
- 4 weeks from exposure and
- 12 weeks from exposure
“During these three months, you should abstain from sex or use condoms. Be considerate of your sexual partners while you are at risk of seroconversion.”
Testing at six months post-exposure is no longer recommended.
7. What else should I know?
- You must complete the 28-day course.
- It is important to remember to take your medication every day at the same time.
- If you miss a dose by accident. Take it as soon as you remember within the 24-hour dosing cycle. It is not necessary to take a double dose’’ after the missed dose is unnecessary. 1 A double dose will increase the risk of side effects.
- Be aware of signs and symptoms (S & S) of acute HIV infection, which is a flu-like illness. You may experience fever, sweats, sore muscles and joints, tiredness, headaches, mouth sores, or a rash. If you develop these while on PEP, follow up with your doctor sooner.
- Talk to your doctor about screening for other sexually transmitted infections at your 4-week follow-up. If you develop symptoms, return sooner.
8. What is my risk of contracting HIV if I don’t take PEP?
Patients often ask me this question. The following table uses statistics from DeHaan E et al. 1
Risk of contracting HIV from an infected source per 10 000 exposures| EXPOSURE TYPE | RISK /10 000 EXPOSURES |
|---|---|
| Receptive anal intercourse | 138 |
| Receptive penile-vaginal intercourse | 8 |
| Insertive anal intercourse | 11 |
| Insertive penile-vaginal intercourse | 4 |
| Oral sex | Low – Accurate estimates of risk are not available |
9. How effective is PEP?
Seroconversion means that you were HIV-negative and became positive.
The bottom line is that seroconversion is rare if you:
- Start PEP early
- Take it as prescribed
- Finish the course
- Avoid re-exposure to HIV
A lot of the data on its effectiveness is from animal studies. It would be unethical to expose trial patients to HIV in order to test the effectiveness. Human studies must analyze patient histories; outcomes are difficult to compare because conditions and protocols are not standardized.
They conclude it is worth taking PEP as it significantly reduces the risk.
An example is data analyzed from a California health clinic. Seventeen seroconversions occurred among 1,744 individuals who followed up within 24 weeks. 1
It is important to know that among these 17 test positives, there were reasons for the increased risk of seroconversion:
- Some had possible re-exposure to HIV.
- Some didn’t take the PEP course correctly.
- Some started PEP between 48 and 72 hours.
This study reinforces the rules. Start PEP early, take it as prescribed, and finish the course. Avoid re-exposure to HIV.
10. How often can I take PEP?
Your first line against possible exposure to HIV and other STIs should be a barrier method, like a condom.
“In my general practice experience, PEP is most requested for unprotected sex with a partner whose status is unknown. 7 out of 10 times, a one-night stand after excessive alcohol consumption.”
PEP is not the answer to repeated risky sexual exposures.
If you need PEP every few months, then you should consider PrEP.
11. Can I start PrEP after PEP?
If you are at risk of recurrent HIV exposure, talk to your doctor about PrEP while you are on your PEP course.
- If you test negative at your 4-week follow-up, you can start PrEP immediately.
- You would take your first Prep tablet the day after your last PEP tablet.
References
- DeHaan E, McGowan JP, Fine SM, et al. PEP to Prevent HIV Infection [Internet]. Baltimore (MD): Johns Hopkins University; 2022 Aug 11. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562734/
- Johns Hopkins University HIV Clinical Guidelines Program 2000-2023. (2023, April 17). PEP to prevent HIV infection. NEW YORK STATE DEPARTMENT OF HEALTH AIDS INSTITUTE CLINICAL GUIDELINES PROGRAM. https://www.hivguidelines.org/guideline/hiv-pep/?mytab=tab_16&mycollection=pep-prep
