What is Post-exposure prophylaxis(PEP) against HIV infection in HK?

Post-exposure prophylaxis (PEP) in HK is a preventive treatment consists of the use of anti-retroviral medication to reduce the risk of HIV infection following a possible exposure to HIV.¹ The effectiveness of PEP for sexual exposure is reported to be as high as 99.96% if PEP was taken correctly.

Pricing/Cost for PEP treatment in HK

PEP Fee : $12,850

The price includes 

1. Doctor consultation,
2. 10 blood tests for pre-treatment and post-treatment
   - Only 2 visits throughout the whole treatment
   - The HIV-1&2 p24 antigen antibody test with a 14-day window period is used before taking the medicine. Compared with the HIV rapid test with a 90-day window period used by other institutions, the window period is shorter and with higher accuracy, which can greatly reduce the risk of unawareness consequences of treatment for HIV infection (eg. HIV drug resistance issues)
3. 28-day medication (one tablet per day, Biktarvy^®)

PEP Treatment (Day 1)

• Doctor Consultation,
• PEP medication, once pill daily (if needed),
• HIV p24 Antibody Antigen Combo test,
• Hepatitis B surface antigen test,
• Hepatitis C Antibody,
• Liver function Test
• Renal function Test

PEP Treatment (Day 45)

• HIV p24 Antibody & Antigen Combo test
• Syphilis Antibody Test
• Syphilis RPR Test
• Hepatitis B surface antigen test
• Hepatitis C antibody test

How to use PEP against HIV in HK?

PEP must be taken within 72 hours (3 days) after possible exposure to HIV, and ideally within a few hours. Research shows that the effectiveness of PEP slowly decreases over time after 2 hours , so the sooner PEP is started, the better the success rate. The full course (28 days) must be completed in order to achieve maximum protection. ²

PEP is a prescription only drug therefore a doctor consultation is required.

Prescription of PEP after 72 hours is not advised as HIV infection could likely be established, and it is associated with increased risk of viral rebound and drug resistance after the discontinuation of PEP treatment . ³

How does PEP work?

After exposure to HIV, the virus will start to replicate locally at the site of entry. If PEP is taken within 72 hours, PEP can stop the infection from spreading by suppressing viral replication. In this case, HIV infection is prevented. Without PEP, the local infection will spread to the nearby lymph nodes within 48 to 72 hours, and eventually into the circulation within 72 to 120 hours, resulting in an established HIV infection.

Research shows that protection against HIV is achieved:

• after 7 days of daily PEP dosing for rectal exposure
• after 7 days, but reaches highest drug concentration after 20 days of daily PEP dosing for genital and direct blood exposure. ⁴

Who should use PEP?

Individuals who experienced a high-risk exposure should consider the use of PEP to prevent HIV infection, including:

1. Unprotected sex with an HIV-positive person or a person with unknown HIV status
2. Condom broke, slipped off or removed during sex
3. People of high-risk groups, including MSM, transgender, intravenous drug users and sex workers
4. Shared needles with an HIV-positive person or a person with unknown HIV status
5. Victims of sexual assault

The risk of HIV transmission is increased if:

• The source with known HIV is in early or late stage of HIV infection
• The source with known HIV has a high viral load
• The source with known HIV is not taking ART, The sexual partner is diagnosed with STDs/STIs
• Exposure in uncircumcised men
• Ulcers are present on the genital or anorectal area
• Wounds are present on the genital or anorectal area, e.g. from rough sex , or sexual assault (wound presence in 10-15% unprotected receptive anal
• intercourse and 55-80% unprotected vaginal penetration)
• Mouth sores/ulcers or gum disease are present (for oral sex)
• Blood was directly exchanged, for example, needle sharing during drug injection

How effective is PEP?

PEP is effective in preventing HIV infection, 99.96% from sexual exposure and 81% from occupational exposure if it is taken correctly. Report shows that PEP can reduce the risk of infection in 81% of occupational exposure, such as accidental needle stick injuries among healthcare professionals. The efficacy of PEP for sexual exposure is reported to be as high as 99.96% if PEP was taken correctly.^5-6

PEP is most effective if:

• Started within 72 hours post-exposure, preferably within 24 hours
• Taken with high adherence for the whole course of treatment (no late or missed dose)
• Abstain from further high-risk behaviors

The effectiveness of PEP is lowered, if:

• PEP was not started soon enough (after 72 hours post-exposure)
• PEP was taken incorrectly or irregularly
• Did not complete the whole course (less than 28 continuous days)
• Continued to engage in high-risk exposure during PEP treatment
• Methamphetamines or alcohol was used, which could impair your judgement and affects drug adherence and increases the likelihood of high-risk exposure during treatment period

Is PEP safe? 

PEP has minimal adverse effects and is generally safe for individuals without HIV.^{[AIDSinfo 2017], [CDC 2016]}

What are the PEP side effects?

Common side effects include: 

• fatigue,
• nausea,
• vomiting,
• headache,
• stomachache,
• flatulence,
• bloating, and
• diarrhea.

The side effects can be managed and are not life-threatening, and will usually subside as treatment progress.

One PEP pill vs two pills?

Currently, PEP could be provided in the form of once-daily or twice-daily dosing. Please consult your doctor for the appropriate choice of selection.

Application of Biktarvy® in Post-exposure prophylaxis (PEP)

The HIV Post-exposure prophylaxis we provide is Biktarvy®, which is taken once a day to reduce the impact of missed doses and have fewer side effects.

The use of twice-daily dosing involves Truvada (or generic version of Truvada) once a day with another raltegravir twice a day, as a combination treatment for PEP, which may pose a threat to the effectiveness of PEP as the user is at risk of missing the afternoon/evening dose. Study shows that nearly 25% of the users missed the afternoon dose when given a twice-daily dosing of raltegravir with once-daily of Truvada as PEP regimen.⁷

On the other hand, another study shows that the use of fixed-dose, once daily PEP regimen have a completion rate up to 92% (REF8), which suggests that adherence rate of the twice-daily regimen is challenging and may result in treatment failure.

Elliot DeHaan et. Al, Post-Exposure Prophylaxis (PEP) to Prevent HIV Infection, 2020

Tests before and after PEP Treatment

HIV testing is required before PEP is prescribed as it is only effective for people without HIV. PEP will not be prescribed if you do not agree to undergo initial HIV testing.

After PEP is started, laboratory monitoring is recommended, including:

• Liver and kidney function (tenofovir is known to cause kidney damage)
• Hepatitis B infection status, as the PEP medication also suppresses hepatitis B viral replication, viral rebound may occur after PEP treatment is finished which could lead to significant worsening of hepatitis B infection
• Other STDs, especially for chlamydia, gonorrhea and syphilis, which are usually found to be co-infected with HIV
• HIV antigen/antibody (combo) test is suggested 45 days post exposure to confirm HIV status. If you keep worrying, rapid HIV antibody test can be done after 90 days (cost $290)

Ref: Post-Exposure Prophylaxis (PEP) to Prevent HIV Infection. Elliot DeHaan, MD, Lead Author, on behalf of Medical Care Criteria Committee of the New York State Department of Health AIDS Institute (NYSDOH AI). Baltimore (MD): Johns Hopkins University; 2020 Jun.

After completion of the PEP treatment, individuals are recommended to have a follow-up HIV testing at 45 days and 90 days post exposure. If the 4th generation (HIV antigen/antibody combo) test is used at 45 days post exposure, sequential HIV testing beyond 90 days is not recommended.

The presence of PEP (antiviral medication) in the circulation may suppress or decrease the rate of HIV replication, thus the RNA viral load (RNA level) could drive to undetected level during the PEP treatment, therefore the HIV RNA test is not recommended during and right after the PEP treatment, which may provide a false negative result. Both the UK and New York State Department of Health AIDS Institute PEP recommended the use of 4th generation tests (HIV antigen/antibody combo) as follow-up test after PEP treatment.

Individuals on PEP are also at elevated risk of contracting other infections, therefore users of PEP are advised to test for diseases such as hepatitis B, hepatitis C, and other common STIs (including chlamydia, gonorrhea, trichomoniasis syphilis) after completion of PEP treatment.

Important Issues for PEP

It is very important for individuals to understand that:

• PEP is for Emergency Situations only
• PEP is given only after a possible HIV exposure
• PEP is not a substitute for other regularly used HIV prevention measures
• PEP is not the right choice for individuals who may be frequently exposed to HIV.
• If you are regularly exposed to HIV, e.g. repeated sexual encounter with a HIV-positive partner, you are advised to talk to your doctor about using PrEP.

HIV cannot be cured. Individual should not rely on PEP to prevent HIV as it does not always work. Use protection during sex is the best way to prevent STI including HIV infection.

(REF1: Post-exposure prophylaxis after non-occupational and occupational exposure to HIV. 2nd ed. Darlinghurst (AU): ASHM; 2016.).
(REF2: Kuhar, D. T., Henderson, D. K., Struble, K. A., Heneine, W., Thomas, V., Cheever, L. W., ... & Panlilio, A. L. (2013). Updated US Public Health Service guidelines for the management of occupational exposures to human immunodeficiency virus and recommendations for postexposure prophylaxis. Infection control and hospital epidemiology, 34(9), 875-892.)
(REF3: Elliot DeHaan et. Al, Post-Exposure Prophylaxis (PEP) to Prevent HIV Infection, 2020)
(REF4: Elliot DeHaan et. Al, Post-Exposure Prophylaxis (PEP) to Prevent HIV Infection, 2020)
(REF5: Cardo DM, et al. A case-control study of HIV seroconversion in health care workers after percutaneous exposure. Centers for Disease Control and Prevention Needlestick Surveillance Group. New England Journal of Medicine. 1997;337(21):1485–90)
(REF6: Thomas, R., Galanakis, C., Vézina, S., Longpré, D., Boissonnault, M., Huchet, E., ... & Machouf, N. (2015). Adherence to post-exposure prophylaxis (PEP) and incidence of HIV seroconversion in a major North American cohort. PLoS One, 10(11), e0142534.)
(Ref 7Mayer KH, et al. Raltegravir, tenofovir DF, and emtricitabine for postexposure prophylaxis to prevent the sexual transmission of HIV: safety, tolerability, and adherence. J Acquir Immune Defic Syndr 2012;59(4):354-359)
(REF Valin N, et al. Evaluation of tolerability with the co-formulation elvitegravir, cobicistat, emtricitabine, and tenofovir disoproxil fumarate for post-HIV exposure prophylaxis. BMC Infect Dis 2016;16(1):718)