How to reduce this risk?

Continued...

How does PEP works?


PEP is recommended because it has been observed that systemic infection does not occur immediately after an exposure and there is a brief window period of opportunity available to contain or eradicate HIV from body before wide spread cellular infection occur. After a needle-stick injury, immune cells (dendritic) in skin present the HIV to T-lymphocytes and natural killer cells. It is seen that in monkey models, Simian immunodeficiency virus (SIV) when injected into vagina, virus is engulfed by immune cells in the vaginal lining. Within 2 days SIV is found in inguinal lymph nodes. Within 5 days SIV infected T-cells and free SIV can be detected in blood stream ⁹. Migration of SIV after rectal or penile tip exposure follows a similar time frame. PEP can stop viral replication during this early period before it gains a 'foothold' in the body.

Is post-exposure prophylaxis recommended for all types of occupational exposures to HIV?



No, because most occupational exposures do not lead to HIV infection. The chances of possible serious side effects (toxicity) from the drugs used for PEP may be much greater than the chance of HIV infection from such exposures. Both risk of infection and possible side effects of drugs should be carefully considered when deciding whether to give post-exposure prophylaxis or not.

The decision to start PEP is made on the basis of degree of exposure to HIV (Exposure Code) and the HIV status of the source (HIV Status Code) from whom the exposure has occurred. The Exposure Code and Status Code are then correlated to arrive at a decision regarding initiation of PEP.

Determination of the Exposure Code (EC):
Exposure code can be defined as per the flow chart given below. It may be classified into three categories, EC-1, EC-2 and EC-3, depending upon the severity of exposure.