July 12, 2024

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What is HIV Post-Exposure Prophylaxis (PEP)?

What is HIV Post-Exposure Prophylaxis (PEP)?

What is HIV Post-Exposure Prophylaxis (PEP)?

December 1, 2023, marks the 36th “World AIDS Day,” with this year’s theme in China being “Unite Society, Jointly Fight Against AIDS.”

While it’s often said that there are no “regrets” in the world, those working in HIV prevention may be familiar with a unique “regret remedy” known as Post-Exposure Prophylaxis (PEP) for HIV exposure.

Origin of HIV Post-Exposure Prophylaxis

Medical professionals frequently encounter situations where accidental exposure to HIV becomes a concern.  PEP, which originated in the late 1980s, was initially designed for healthcare workers to reduce the risk of infection after accidental exposure to the HIV virus. Over the years, it has become available to the general public.

Effectiveness of PEP

In China, occupational post-exposure prevention has been in practice for over two decades, with over a thousand cases implemented, and there have been no reported cases of PEP failure. This underscores the effectiveness of PEP in preventing HIV transmission.


Understanding HIV Post-Exposure Prophylaxis

HIV Post-Exposure Prophylaxis refers to the early (within 72 hours, ideally within 2 hours) use of specific antiretroviral drugs by individuals not yet infected with HIV but exposed to a high-risk situation, such as engaging in fluid exchange with an HIV-positive person or someone with an unknown infection status.

Key points about PEP:

  1. It does not cure those already infected but protects the uninfected.
  2. It is effective after contact with HIV-positive individuals or those with an unknown status.
  3. It must be taken within 72 hours (ideally within 2 hours) of exposure.

Components of PEP

PEP is not a single pill; it involves a combination of three antiretroviral drugs. Commonly used PEP regimens in China include (choose one from each category): (TDF or TAF) + (FTC or 3TC) + (DTG or RAL). Alternatively, tenofovir disoproxil fumarate and emtricitabine can be replaced by emtricitabine/tenofovir alafenamide or lamivudine, and dolutegravir or raltegravir can be replaced by rilpivirine.

It’s important to note that some individuals may experience side effects such as headaches, insomnia, dizziness, fatigue, nausea, vomiting, or gastrointestinal discomfort. Most of these symptoms resolve on their own. However, strict adherence to the 28-day regimen is crucial, as discontinuation may lead to viral resistance and treatment failure.


Blocking the Virus, Every Second Counts

The emphasis on taking medication within 72 hours is closely related to how the virus invades the body.

After entering the subcutaneous or mucous membrane, the virus is first recognized by dendritic cells, infects nearby CD4 cells, spreads to nearby lymph nodes, and then further disseminates. The time from local infection to spread is generally 72 hours. While the drugs won’t kill the virus, they create a “barrier” that confines the virus within certain cells, preventing replication and spread. Early medication reduces infected immune cells, limits the virus’s spread, and enhances the efficacy of blocking drugs.


How to ask for Blocking Medication?

For professionals at risk of HIV exposure in their work, such as healthcare workers and police, this drug regimen is effective and free if deemed an occupational exposure.

For those who engage in high-risk behavior and need post-exposure prevention, they can seek medication from HIV infection specialized clinics, disease control agencies, VCT clinics, or social organizations. The cost varies depending on the drug combination.


What is HIV Post-Exposure Prophylaxis (PEP)?



In practice, these agencies will ensure that only people who meet all five of the following conditions can start using PEP:

(1) Aged 18 years and above, those under 18 years old need guardian’s consent;

(2) HIV antibody test negative;

(3) The exposure time does not exceed 72 hours;

(4) Exposure source and behavioral assessment analysis indicate that the inquirer is at higher risk of HIV infection;

(5) Agree to take medications on time, ensure compliance, and participate in follow-up tests on time.



While post-exposure prevention has a high success rate, it’s not 100% guaranteed. It is not a routine preventive measure, and the consistent use of condoms and other preventive methods remains crucial for preventing HIV infection.

What is HIV Post-Exposure Prophylaxis (PEP)?

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