Postexposure Prophylaxis for HIV infection

The use of zidovudine in healthcare workers exposed to needle sticks reduced seroconversion rate to HIV positivity by 81% in (Cardo DM).

Antiretroviral therapy may be administered for prophylaxis againstafter exposure to HIV through sexual contact or injection drug use.

Postexposure prophylaxis use presupposes that exposed individuals are HIV negative.

Overall rate of HIV transmission via percutaneous inoculation by a needle or other instrument that pierces the skin is 0.3%.

Higher rates transmission of HIV, following exposure to a percutaneous inoculation, is associated with a needle that was used to cannulate a blood vessel in a source patient, the presence of advanced HIV in the source patient, a deep needlestick, and visible blood on the source instrument (Cardo DM).

While any exposure that pierces the skin may transmit infection it is generally held that a puncture must draw blood for there to be a significant risk of infection.

Splashes of HIV infected material, mucous membranes or broken skin is associated with an estimated risk for exposure .09% (Ippolito G).

Estimated risk is 1% to 30% for transmission of HIV infection with receptive anal intercourse.

Estimated risk is 0.1 to 10% for transmission of HIV infection with insertive anal intercourse.

Estimated risk is 0.1 to 10% or more receptive vaginal intercourse (Powers KA, Boily MC).

Estimated risk is 0.1 t0 1.0% with insertive vaginal intercourse.

Oral sexual contact said to be less risky for HIV transmission.

The risks of sexual transmission of HIV are difficult to quantify and are influenced by the presence or absence of a genital ulcer, cervical or anal dysplasia, the presence or absence of circumcision, the viral load that is transmitted, the virulence of the viral particles and the presence of comorbid disease.

Estimated risk for individuals sharing needles for injection drug use associateD with a transmission risk of approximately 0.67% per needle sharing contact (Kaplan EH).

The use of postexposure prophylaxis hinges on the likelihood that the source patient is HIV-positive.

The use of the highly sensitive rapid ELISA test is essential to test the source patient, as a negative result obviates prophylactic treatment.

Rarely, a negative result in a source patient with recent high-risk behavior, may still require treatment pending later studies on the source patient.

Postexposure chemoprophylaxis recommended after exposure ti HIV infected fluids that should start wthin 72 hours.

Daily antiviral preexposure prophylaxis with oral tenofovir fumarate and co-formulated emtrictabine/tenofovir fumarate is efficacious for the prevention of HIV acquisition in diverse populations.

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