If the source individual cannot be identified or tested, decisions regarding follow up should be based on the exposure risk and whether the source is likely to be a person who is HIV positive. Follow up HIV testing should be available to all workers who are concerned about possible HIV infection through occupational exposure.

Testing & counselling following exposure
The exposed HCP is tested for HIV immediately following exposure, at six weeks following exposure and again at twelve weeks after the exposure. On all the occasions, HCP must be provided with a pre-test and post-test counselling. HIV testing should be carried out on three ERS (ELISA/Rapid/Simple) test kits or antigen preparations. A complete blood count renal function and liver function tests should be done 2 weeks after starting treatment HCP should be advised to report any flu like illness, fever, rash, muscle aches, swollen glands etc He/She should be advised to refrain from donating blood, semen or organs/tissues and abstain from sexual intercourse. In the case sexual intercourse is undertaken a latex condom be used consistently. In addition, women HCP should not breast-feed their infants during the follow up period.

How soon after exposure to HIV should treatment start?


Treatment should be started promptly, preferably within 1 - 2 hours after the exposure or as soon as possible. Although animal studies suggest that treatment is substantially less effective when started more than 24 - 36 hours after exposure, it is not known if this time frame is the same for humans. Starting treatment after a long period (for example, 1-2 weeks) may be considered for the highest risk exposures; even if HIV infection is not prevented, early treatment of initial HIV infection may lessen the severity of symptoms and delay the onset of AIDS.

How long do the drugs need to be taken?


The optimal course of treatment is unknown; since it has been observed that 4 weeks of ZDV appears to provide protection against HIV infection, if tolerated, treatment should probably be taken for 4 weeks.

How safe are these drugs?


While administering PEP, the important goal is completion of a 4 week PEP regimen. So the toxicity profile of drugs used is a relevant consideration. NRTIs are associated mainly with gastrointestinal side effects like nausea, diarrhoea; however ddI has been associated with fatal and non-fatal pancreatitis among HIV infected patients treated for more than 4 weeks. The use of PI has been shown to be associated with rise in blood sugar, triglycerides, IDV with nephrolithiasis (so more water intake), NFV with diarrhoea, NVP with hepatotoxicity and EFV with dizziness, insomnia etc. All these drugs have interactions with other drugs also.

It has been observed that 50 % of HCP experience adverse symptoms like nausea; malaise, anorexia and headache while taking PEP and approx. 33% stop taking PEP due to adverse signs and symptoms. The side effects are more among HCP taking three-drug regimen as compared to those on two-drug regimen. NVP has been associated with serious hepatic toxicity in a number of cases and is no longer recommended for PEP.

Should pregnant women take these drugs?


Based on limited information available, anti-retroviral therapy taken during 2^nd and 3^rd trimester of pregnancy have not caused serious side effects in mothers or infants. There is very little information on their safety in the 1^st trimester. If the HCP is pregnant at the time of exposure to HIV, the designated authority/physician must be consulted about the use of the drugs for PEP. EFV is not used during pregnancy. D4T and ddI, IDV may be dangerous. However, Zidovudine has been found to be quite "safe".

Availability of PEP
In most developing countries of world, PEP regimens are now widely known. However, there might be operational difficulties in early administration of drugs e.g. non availability of drugs resource person after "office hours" of hospital, lack of adequate testing/counselling services, monitoring of PEP toxicity and expert advice in difficult situations.

In our country, National AIDS Control Organisation, Government of India is providing drugs for PEP free of cost to all HCP in all Government Hospitals. An extensive plan has been developed whereby hospital ensures that drugs are accessible all 24 hours at a place in emergency room, more than one resource persons are identified to decide on administering PEP and adequate counselling and testing facilities are available to all categories of HCP. A proper "exposure report" is made in a pre designed form and full follow up of HCP for at least six months is ensured.