What is PrEP?
Pre-exposure prophylaxis, PrEP, is an HIV prevention strategy for HIV-negative individuals to take anti-retroviral medication to prevent HIV infection from exposure to the virus by suppressing HIV viral replication.
There are currently two medications approved by the US FDA for use as PrEP: Truvada® (emtricitabine and tenofovir disoproxil fumarate; EM-TDF) and Descovy® (emtricitabine and tenofovir alafenamide; EM-TAF). Generic versions are also available but are not FDA-approved for PrEP purposes.
New EM-TAF vs old EM-TDF
Clinical trials suggested that the new EM-TAF is not inferior to the old EM-TDF in terms of their efficacy in preventing HIV infection (0.16 vs 0.34 infections/100 people/year for EM-TAF and EM-TDF, respectively), and EM-TAF is associated with a lower incidence of adverse events (1%) when compared to the old EM-TDF (2%). The new EM-TAF is also reported to be safer than EM-TDF as it is associated with lower risk of renal toxicity and reduced bone mineral density loss.1-2
PrEP Cost
Truvada® : $7,750/Bottle
Descovy® : $8,350/Bottle
Medicine above can only be purchased after doctor consultation.
Check-ups before taking PrEP
To order PrEP medicines in Hong Kong or online, a doctor's prescription or documentation of recent HIV, hepatitis B, kidney and liver function test results is required. While taking PrEP, HIV testing is also recommended every 3 months, kidney and other STD tests are recommended every 6 months during PrEP.
PrEP Test Fee - Basic
$980, including the following tests and related report documents.
- HIV p24 antigen and antibody test
- Hepatitis B Surface Antigen Test
- Liver function test
- Kidney function test
Reporting time : 1-2 days (working days)
Effectiveness of PrEP
According to CDC, If taken correctly as prescribed (oral daily dose), PrEP can lower the risk of HIV transmission by 99% from sexual activities, and by 74% among intravenous drug users . The risk of contracting HIV can be further reduced if other prevention methods (such as using condom) are used in conjunction with PrEP.3
How to take PrEP
There are currently two options to take PrEP:
| Daily oral regimen of taking one pill per day |
| which provides the highest level of protection when taken as prescribed. The daily use regimen is the only FDA-approved schedule for using PrEP. |
| “On demand” |
| regiment also known as “event-driven” or “non-daily use”, which is taken according to the “2-1-1” schedule – two pills taken 2-24 hours before sex, followed by one pill 24 hours after the first dose, and one pill 24 hours after the second dose. The “2-1-1” schedule has been scientifically proven to provide sufficient protection for MSM when having unprotected anal sex. However, the effectiveness of the “on-demand” PrEP regimen is currently unavailable for intravenous drug users, transgender, heterosexual men and women. This “on-demand” schedule use of PrEP is NOT FDA-approved and is NOT included in the CDC guideline. |
Time to PrEP effective
PrEP provides maximum protection after 7 days of daily dose for receptive anal sex, and after 21 days of daily dose for receptive vaginal sex. The effectiveness of PrEP for insertive vaginal and anal sex is currently unavailable.
Who should take PrEP?
1. Individuals who engaged in anal or vaginal sex in the past 6 months with
- a sexual partner with known HIV infection (especially if the partner has unknown or detectable viral load), or
- inconsistent use of condom, or
- a positive STD diagnosis made in the past 6 months
2. Individuals who inject drugs and
- your injection partner is HIV-positive (especially if the partner has unknown or detectable viral load), or
- share needles and/or syringes with others
3. Individuals that have been prescribed PEP (post-exposure prophylaxis) before
- multiple times previously, or
- continue to engage in high-risk exposure behaviours
4. Woman with a partner with HIV who
- Considering of getting pregnant. PrEP medication is safe for pregnancy and could protect the woman and infant from HIV infection during pregnancy and breastfeeding.
It is important for individuals to consult doctor before initializing PrEP treatment, especially for the important information regarding of the starting / stopping of PrEP and necessary test schedule along the period.
Risk and Side effects of PrEP4
1. Risk of long term use or medication toxicity
Study suggested that daily use of PrEP can result in serious side effects, including abnormal liver function, kidney damage, pancreatitis and bone thinning. Therefore, regular monitoring of liver function, kidney function and bone mineral density are recommended for all PrEP users.
2. Side effect of drug
Regular monitoring during the use of PrEP is recommended to prevent long-term medication toxicity from long-term use. The majority of side effects reported are related to the gastrointestinal tract which range from mild to moderate, including nausea, vomiting and diarrhoea.
3. Risk of STI infection
The rate of condom use among PrEP users is low due to the fact that the fear of contracting HIV is greatly reduced by PrEP, which results in high STI infection rate. One study reported the incidence of STI increased from 69.5/100 person/year prior to enrolment to 98.4/100 person/year during follow-up. Recent findings reported the incidence of rectal chlamydia and syphilis increased by 29% and 164% respectively among PrEP user. Education on taking PrEP as prescribed and the correct and persistent use of condom during sex are vital in preventing the transmission of HIV and STIs. 5
Recommended tests before and after PrEP
According to the WHO, testing for HIV infection status is required before initiating PrEP. HIV testing is suggested every three months and before restarting of PrEP.
Regular monitoring of liver function, renal function, hepatitis B infection/immunization status and STI infection, including syphilis, gonorrhea and chlamydia, before and after starting of PrEP are also recommended.
| Basic PrEP Screening Package | $980 |
|
| Comprehensive PrEP Screening Package | $2,500 |
|
(Ref1: Kenneth H Mayer, Lancet 2020; 396: 239–54 )
(REF2: Fong, T. L., Lee, B. T., Tien, A., Chang, M., Lim, C., Ahn, A., & Bae, H. S. (2019). Improvement of bone mineral density and markers of proximal renal tubular function in chronic hepatitis B patients switched from tenofovir disoproxil fumarate to tenofovir alafenamide. Journal of viral hepatitis, 26(5), 561-567.)
(REF3: Massud, I., Ruone, S., Zlotorzynska, M., Haaland, R., Mills, P., Cong, M. E., ... & García-Lerma, J. G. (2020). Single oral dose for HIV pre or post-exposure prophylaxis: user desirability and biological efficacy in macaques. EBioMedicine, 58, 102894.)
(Ref4: MichaelW. Traeger et. Al. (2019) Association of HIV Preexposure Prophylaxis With Incidence of Sexually Transmitted Infections Among Individuals at High Risk of HIV Infection. JAMA April 9, 2019 Volume 321, Number 14. )
(Ref5: Raymond A. Tetteh et al (2017) Pre-Exposure Prophylaxis for HIV Prevention: Safety Concerns Drug Saf (2017) 40:273–283)
