Post-exposure prophylaxis

Post-exposure prophylaxis (PEP) is any prophylactic treatment started immediately after exposure to a pathogen (such as a disease-causing virus), in order to prevent infection by the pathogen and the development of disease.

Rabies

PEP is commonly and very effectively used to prevent the outbreak of rabies after a bite by a rabid animal.

The treatment consists of repeated injections of rabies vaccine and immunoglobulin.cite web |url=http://www.who.int/rabies/human/postexp/en/index.html |title=WHO | Guide for post-exposure prophylaxis |accessdate=2008-03-05 |format= |work=]

HIV

In the case of HIV infection, post-exposure prophylaxis is a course of antiretroviral drugs which is thought to reduce the risk of seroconversion after events with high risk of exposure to HIV (e.g., unprotected anal or vaginal sex, needlestick injuries, or sharing needles).

To be effective, treatment should begin within an hourcite web |url=http://bja.oxfordjournals.org/cgi/content/abstract/84/6/767 |title=Ignorance of post-exposure prophylaxis guidelines following HIV needlestick injury may increase the risk of seroconversion -- Diprose et al. 84 (6): 767 -- British Journal of Anaesthesia |accessdate=2008-03-05 |format= |work=] of possible infection, and no longer than 72 hours post-exposure. Fact|date=March 2008 Prophylactic treatment for HIV typically lasts four weeks.cite web |url=http://hab.hrsa.gov/tools/HIVpocketguide/PktGPEP.htm |title=HIV/AIDS Bureau - HIV Care Pocket Guide 2006 - Occupational HIV Postexposure Prophylaxis (PEP) |accessdate=2008-03-05 |format= |work=]

While there is compelling data to suggest that PEP after HIV exposure is effective, there have been cases where it has failed. Failure has often been attributed to the delay in receiving treatment, the level of exposure (i.e., the viral load received), or both. However, for non-occupational exposures, the time and level of exposure are based on patient-supplied information; absolute data is therefore unavailable. PEP can also slow down the development of antibodies, potentially causing false negatives on a later HIV test. Doctors will advise patients who received PEP to get a test at 6 months post-exposure as well as the standard 3 month test. In certain cases PEP has been known to slow the development of antibodies by beyond 12 months.

The antiretroviral regimen used in PEP (see highly active antiretroviral therapy) requires close compliance and can have unpleasant side effects including malaise, fatigue, diarrhea, headache, nausea and vomiting.cite web |url=http://hab.hrsa.gov/tools/HIVpocketguide/PktGPEP.htm |title=HIV/AIDS Bureau - HIV Care Pocket Guide 2006 - Occupational HIV Postexposure Prophylaxis (PEP) |accessdate=2008-03-05 |format= |work=] Pleasant side effects have been reported within the first 4 days of treatment which mimic anti-depressant properties, however these are rare and none of these effects are known to have been reported past this period.Fact|date=March 2008

See also

* Pre-exposure prophylaxis (PrEP)

References