HIV: What is pre-exposure prophylaxis?


Pre-exposure prophylaxis (PrEP) is the newest method of preventing HIV transmission, explains Dr Avron Urison of AllLife.

PrEP is a new HIV-prevention method, in which people who do not have HIV, take a daily pill to reduce their risk of becoming infected. Taking medicine before exposure to an infectious agent is nothing new. Public health officials often advise travellers to take medications or be vaccinated before they visit areas where infectious diseases, such as malaria or typhoid, are common. Researchers believe that the same concept may work to protect you from HIV.

When used consistently, PrEP has been shown to be effective in men who have sex with men (MSM) and heterosexually-active men and women. A CDC (Centre for Disease Control) study is also underway to evaluate whether PrEP is safe and effective in reducing the risk of HIV infection through injection drug use, but those results are not yet available.

Findings in study

Based on studies to date, in July 2012 the US Food and Drug Administration approved the combination medication tenofovir disoproxil fumarate plus emtricitabine (TDF/FTC), known commonly as Truvada, for use as PrEP among sexually active adults at risk for HIV infection.

For some individuals at high risk for HIV infection, PrEP may represent a much-needed additional prevention method, but it will not be right for everyone and is not intended to be used in isolation, but rather in combination with other methods to reduce the risk of getting HIV infection. If it is delivered effectively and targeted to those at highest risk, PrEP may play a role in helping to reduce the significant continuing toll of new HIV infections.

 CDC is currently working with partners to ensure safe and effective PrEP use and begin to address key questions about acceptability, access, adherence, behavioural risks, and patient outcomes in community settings.

Importantly, anyone considering using PrEP should know:

  • PrEP should only be used among individuals who have been confirmed to be HIV-negative.  Initial and regular HIV testing is critical for anyone considering using PrEP.  All individuals considering PrEP must also be evaluated for other health conditions that may impact PrEP use.
  • PrEP should never be seen as the first line of defense against HIV.  It was only shown to be effective in clinical trials when provided in combination with regular HIV testing, condoms, and other proven prevention methods.
  • Taking PrEP daily is critical.  No other dosing regimen was evaluated in these studies.
  • PrEP must be obtained and used in close collaboration with health care providers to ensure regular HIV testing, risk reduction and adherence counselling, and careful safety monitoring.  Anyone considering using PrEP should speak with his or her doctor.
  • PrEP has only been shown in clinical trials to reduce HIV infection among heterosexual men and women and among men who have sex with men.  At this time, there are no data on its benefits or risks among injection drug users.
  • Because pregnant and breastfeeding women were excluded from participation in PrEP trials, further evaluation of available data will be needed before any recommendations can be made regarding the use of PrEP for women during conception, pregnancy, or breastfeeding

In summary, the latest PreP scientific studies seem to show that it is affective. However, the studies also show low adherence rates for a number of reasons. In particular, in the South African situation, it may be good for certain vulnerable groups, but both the expense and the difficulties in a large scale operational roll out make it unlikely to be used on any large scale.

(Dr Avron Urison is Medical Director at AllLife Pty Ltd - providers of life insurance for HIV positive individuals.)  

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