Hiv infection, post-exposure prophylaxis

• Remember! The average risk of HIV infection after percutaneous exposure to the blood of HIV-infected persons is about 0.3% according to the data available to date; i.e. on average, one in 330 exposures leads to HIV infection. In contrast, the average risk of infection after exposure to mucous membranes and after exposure to inflammatory changed skin parts is around 0.03% (one HIV infection for 3300 exposures). In all cases, individual differences are determined by the amount of infectious blood, the virus concentration and the duration of exposure.

• Notice! HIV-PEP should be started as early as possible after exposure. The best results are expected if prophylaxis is started within 24 hours, or even better within 2 hours. If there are already more than 72 hours between exposure and the possible start of prophylaxis, prophylaxis can no longer be recommended according to the current state of knowledge (exceptions see above). Alternatively, HIV monitoring (HIV antibody tests e.g. 6 and 12 weeks after exposure, in case of clinical symptoms possibly HIV-PCR) can be offered and, if necessary, an early therapy can be considered if there is evidence of viremia.

• According to the current state of knowledge, exposure to HIV is assumed to occur in:
• injury with HIV-contaminated instruments or injection equipment
• Wetting of open wounds and mucous membranes with HIV-contaminated fluids
• unprotected sexual intercourse with a person infected with HIV
• use of HIV-contaminated injection equipment and
• Transfusion of HIV-contaminated blood or blood products.
• Probably injuries to hollow needles are more dangerous than surgical needles. Transmission of infection must also be considered after criminal attacks with possibly infectious weapons or objects (stabbing tools, etc.) as well as injuries to several people involved.
• Occupational HIV transmission has so far only occurred via blood or virus concentrate (virus culture), especially in the case of:
• Stab and cut injuries
• Contact of infectious materials with an open wound or non-intact (damaged) skin of the exposed person
• Mucosal exposure (including blood splashes in the eye).

• No recapping of protective caps on used needles!
• Orderly, well thought-out and concentrated working method for activities involving injuries.
• Use of safety needles (Blunt-Needles) for blood collection and indwelling cannulae.
• Use of shatterproof and puncture-proof disposal containers for used cannulas and other disposable materials at the place of handling or take the containers with you at every corresponding intervention (avoid overfilling!).
• Wear protective gloves against possible contact with infectious material such as blood, saliva, etc. (also applies to cleaning and disinfection measures including instrument reprocessing).
• Use protective goggles, if necessary also closed at the sides, if there is a risk of splashing infectious material into the eye (e.g. during bronchoscopy, intubation, transurethral catheterisation, childbirth, dental treatment, working with plasma / serum / liquor).
• Medical personnel should be vaccinated against HBV. HBV vaccination must be offered free of charge to all employees at risk of infection during recruitment and occupational health examinations. The same applies to non-medical personnel, including those from external companies, who perform cleaning and disposal services in work areas where there is a risk of infection.

To assess the concrete risk of infection after HIV exposure and to clarify a possible drug resistance of HIV, the following questions should be answered:

• When did the possible contact with HIV take place?

• From which index person does the material come?

• How was HIV possibly transmitted? (e.g. through hollow cannulas? through mucous membrane contact?)

• How deep are existing injuries (always only after bleeding induction and antiseptic)? Were blood vessels opened?

• Does the injured instrument bear traces of contamination with blood?

• Is the index person demonstrably infected or how likely is an HIV infection?

• At what stage of HIV disease (clinical manifestation, CD4 cell count) is the index person?

• How high is the current viremia of the index person measured by the HIV-RNA copies/ml?

• Is the index person treated with antiretroviral drugs? If so, with which drugs over which period of time?

• Are resistances known?

• What other measures have been taken so far?

• Prophylaxis modification: A modification of these prophylaxis schemes should always be considered if the index person has been antiretrovirally pre-treated or has a detectable viral load under antiretroviral treatment. The general guidelines for modification are the rules of sequential combination therapy of HIV infection:

• if possible, use of at least two drugs with which the index patient has not been treated before

• Consideration of known cross-resistance

• in index patients with NNRTI pre-treatment and virological failure as well as in patients with virological failure pre-treated with pro¬tease inhibitors, a boosted protease inhibitor (e.g. lopinavir in fixed combination with ritonavir [Kaletra]) should be preferred.

• In index patients with known multidrug-resistant virus, the use of newer drugs such as darunavir (Prezista) and enfurvitide (Fuzeon) for post-exposure prophylaxis may also be considered.

• The combination to be administered in individual cases should then additionally be based on the current status of therapy recommendations, as summarised with findings on side effects and interactions or on possible late effects to be expected, e.g. in the German-Austrian consensus recommendations on antiretroviral therapy. In these cases, HIV-PEP should be carried out in cooperation with a centre for HIV therapy or a physician experienced in HIV therapy. In case of uncertainty regarding the combination of drugs, however, every HIV-PEP should be started with standard prophylaxis!

• Loss of time results in a reduced protective effect of PEP! If the suggested medication is not immediately available, other proven and immediately available medication can be used, e.g. Stavudine instead of Tenofovir or Zidovudine, Didanosine instead of Emtricitabine or Lamivudine (but no combination of Zidovudine + Stavudine or Didanosine + Stavudine, Nelfinavir (unboosted), Indinavir (boosted or unboosted) or Saquinavir (only boosted) instead of Lopinavir/ritonavir.

• Current knowledge on pre- and clinical data on antiretroviral substances in pregnancy must be obtained and reviewed. At present, no substance can be classified as completely harmless for both treatment and prophylaxis. Since zidovudine and lamivudine have the most extensive clinical experience to date, the standard PEP for a pregnant woman should contain these drugs, e.g. in the form of a combination of:

• zidovudine + lamivudine + lopinavir/rit (Combivir 2 times/day 300/150 mg + Kaletra 2 times/day 400/100 mg).

• As far as investigated, all antiretroviral drugs can be detected to a relevant extent in breast milk when taken. In the case of post-exposure combination therapy during the breastfeeding period, a breastfeeding break or weaning is therefore recommended, at least for the affected period.