Page 267 - AIDSBK23C

Page 267

OCCUPATIONAL AND NON-OCCUPATIONAL HIV EXPOSURES

Transmission of HIV from infected patients to health care workers by accidents involving
parenteral exposure is highly unlikely--a risk of about 0.3% per exposure[161] Since this figure
represents the findings of studies of exposures in high risk situations to patients with advanced
AIDS with higher viral titers, the average risk in most health care delivery settings is much less.
The risk for HIV seroconversion is increased with a deep injury, injury with a device visibly
contaminated with patient blood, injury involving a procedure in which a needle is placed in a
patient’s artery or vein, and injury involving a patient progressing to death from AIDS within
two months of the injury. Health care workers who seroconvert are less likely to have had
postexposure zidovudine prophylaxis. These findings are consistent with the observations that
the risk for HIV infection after a percutaneous exposure increases with a larger volume of blood
and with a greater HIV viremia in the patient’s blood.[161]
However, rare inadvertent exposures to HIV or other infectious agents may occur despite
the best practices of health care workers. When such incidents occur, the situation that led to the
exposure must be documented, reported as an industrial accident, and investigated to determine
why it happened and how it could be prevented in the future. Persons exposed to HIV should
have serologic testing carried out immediately for baseline determination of serologic status and
followed by additional testing at 3 months, and 6 months after initial exposure. Persons with
work-related exposure to HIV can still acquire HIV infection outside of the workplace, and
persons in known risk groups with exposure to HIV may be employed in settings of occupational
exposure. There is no laboratory method for making a distinction among the means for HIV
exposure.
There is experimental and epidemiologic evidence that administration of antiretroviral
therapy beginning soon after exposure to HIV and continuing for several weeks may prevent
HIV infection from occurring. There is insufficient data in humans to fully verify this
observation, and persons accidentally exposed to HIV have seroconverted despite immediate
prophylaxis, but a risk reduction of 81% with post-exposure prophylaxis with zidovudine
following percutaneous injuries has been reported.[1070]
The standard 4-week regimen consists of two drugs (zidovudine and lamivudine, or
tenofovir and emcitrabine) started as soon as possible after HIV exposure through percutaneous
or mucosal routes. The standard two-drug regimen is indicated when the source proves to be
asymptomatic, with low viral load. If the source is symptomatic with high viral load, then
additional drugs can be added to the basic two-drug regimen (these may include: lopinavir with
ritonavir, atazanavir with ritonavir, darunavir with ritonavir). If the source person is determined
to be HIV negative, treatment should be discontinued. Antiretroviral treatment is not indicated
for contact between intact skin and blood or other body fluids contaminated by HIV. The degree
of risk of exposure may be stratified to determine the appropriateness of using postexposure
prophylaxis.[131,160]
Adverse side effects of such prophylaxis are frequent, but minor, with about three fourths
of persons reporting nausea, malaise or fatigue, and headache. The serious side effect of bone
marrow suppression is less frequent. Though pregnancy is not a contraindication to
postexposure prophylaxis, use of efavirenz should be avoided. Nevirapine should be avoided
because of potential hepatotoxicity.[131,161]