Is PrEP Effective After 3 Days?

Prevention of diseases is one of the ways to to reduce cost in the health sector. Is PrEP effective after 3 days?

In HIV program, epidemic control is one of the goals and at such we have to talk about PrEP. Is PrEP really effective?

Can I be infected while on PrEP? Can I infect someone while on PrEP? Can anyone take PrEP? Sit back and your questions will be answered.

What is PrEP

Is PrEP effective after 3 days? PrEP (Pre-exposure prophylaxis) is the taking of HIV medication by an individual who is HIV negative from contracting HIV. A lot of people wonder if this drug actual works. Does it work? 

Eligibility Criteria for PrEP use

Not everyone is eligible for PrEP use. The following are the criteria an individual must meet before being initiated on PrEP

  1. HIV negative: Before an individual is initiated on oral PrEP, a test is carried out to ascertain the HIV status of the individual. The test result must come out negative to be eligible.
  2. No suspicion of acute HIV infection: An individual that shows signs of acute HIV infection such as fever, headache, rash, sore throat is not eligible for PrEP. If an individual is experiencing the above symptoms in the last 14 days, defer PrEP and repeat HIV test in 28 days. If test comes out negative, consider initiating PrEP.
  3. No contraindications to any PrEP medicines: This means that there must be no allergies in the use of PrEP.
  4. No known exposure to HIV in the past 72hrs: If there has been an exposure to HIV infection in the past 72 hours such as sexual intercourse, blood transfusion, needle prick, the individual should be placed on PEP (post exposure prophylaxis) for 28 days and not PrEP. If after 28 days, a test is done and comes out negative, PrEP should be given without gap.
  5. Creatinine clearance ≥ 60ml/min: Cockcroft-Gault equations can be used to calculate the creatine clearance.
  6. Willingness to use PrEP and be tested periodically: PrEP shouldn’t be forced on anyone because it creates room for no adherence.
  7. At substantial risk of HIV infection.

Note that you can only be eligible when you meet all the 7 criteria above.

How do I know that I am at risk of HIV infection?

  1. Having a HIV positive sex partner and partner not virally suppressed.
  2. Used PEP for sexual exposure.
  3. Inconsistent use of condom.
  4. Recent sexual transmitted infection (STI).
  5. Sexual partner at high risk of HIV infection.

PrEP Regimens

There are 3 PrEP regimens available. The one in the country might depend on cost and country’s treatment guidelines.

  1. Single tenofovir disoproxil fumarate (TDF): It is taken in tablet form and the dosage is 300mg. it could be considered as PrEP for heterosexuals.
  2. Tenofovir combined with lamivudine (TDF/3TC): Includes 300mg of TDF and 300mg of 3TC.
  3. Tenofovir combined with emtricitabine (TDG/FTC): Also taken in tablet form. It is effective and safe for heterosexual men and women, MSM (men that have sex with men) and transgender women. It comes in 300mg of TDF and 200mg of FTC.

Dosing Frequency of PrEP

There are two types of dosing;

  1. Daily dosing
  2. Event-driven dosing

Women (cis- and transgender) and men that have sex with women

  • Daily dosing: Take PrEP 7 days before first exposure to reach level for optimal protection, then through period of risk and continue for 28 days after last exposure before stopping.

Men that have sex with men (MSM)

  • Daily dosing: recommended for men that have sex with men (MSM) frequently. 2 Pills should be taken 2-24 hours prior to first sex act. Followed by continuous daily use of a single pill/day throughout the period of risk. Continue daily dosing for 2 days after last exposure before stopping.
  • Event-driven (on-demand, event-based, 2+1+1) dosing: Recommended for men that have sex with men (MSM) occasionally. Take 2 pills on day 1 (protection within 2-24 hours after double dose), then single daily pill for 2 days after last exposure before stopping.

Special Situations

  • PrEP in Pregnancy: It is safe for pregnant and breast-feeding mothers because it doesn’t interfere with birth outcomes, infant birth weight and it doesn’t cause congenital malformations.
  • Can I be infected while on PrEP: There are ways you can be infected while on Prep;
  1. You might have been infected even before starting PrEP but not detected during testing probably because you were still in the window period.
  2. Missing your dose can reduce the effectiveness of PrEP.
  3. Infected with a strain that is resistant to the PrEP drug.
  • Can I infect someone while on PrEP: You can infect someone while on PrEP if you get infected while on PrEP (see scenarios above).
  • Missed Dose: Take it immediately you remember.
  • PrEP and Condom: PrEP prevents HIV infection only. It doesn’t prevent STIs, therefore condom should be combined with PrEP. Note that STIs increase your chances of contracting HIV.
  • Is PrEP effective after 3 days?: It depends on the type of dosing frequency. See dosing frequency above for more information.
  • PrEP and Contraceptives: PrEP is safe for women using any type of contraceptive.

Note that PrEP can be taken with or without food and it is 90% effective if taken appropriately. We want to make the world a better place by achieving epidemic control of HIV.