What is PEP, what is PrEP therapy

What is PEP?

PEP involves taking a short course of ARV drugs, usually for a month, after a high-risk exposure. Though experts believe that PEP works, based on large amounts of data in health care workers who were exposed to infected blood, it is not possible to ethically test this in humans for sexual exposure. To be most effective, PEP should be started immediately after possible exposure, waiting no more than 72 hours.

The term "post-expositional prophylaxis" (PEP) refers to activities to prevent infection, which include: first aid, counselling and risk assessment, HIV testing based on consent and, depending on the risk assessment, dose of short (28 days) antiretroviral treatment, with monitoring and support.

What is PrEP?

PrEP or "pre-expositional prophylaxis" involves having an uninfected person take ARV drugs (usually Viread or Truvada) before, during and after possible high-risk exposures to reduce the risk of becoming infected. The earliest PrEP studies call for taking either Viread or Truvada every day, even during periods of minimal or low-risk sexual activity. Future studies may explore intermittent dosing strategies.

This method is still being tested and there are no guarantees of its safety and effectiveness. There are a number of reasons for this, including the fact that we don't yet know how frequently a person needs to get tested while on PrEP. If a person does become infected, and continues to use Truvada before the next test, they could become resistant to one or both of the drugs contained in the combination pill. There are four other PrEP studies currently in progress, and it will be important to see how well PrEP works before firm recommendations can be issued.

So far, the evidence that brings hope for success of PrEP is the experience with the prevention of vertical transmission (from mother to child), the experience of post-expositional prophylaxis and the results obtained in separate tests conducted on animals.