Post-exposure prophylaxis (PEP) is a health measure aimed at preventing the development of infection after potential exposure to pathogens. Regarding HIV, PEP implies providing a wide range of services to prevent HIV infection after exposure or with high probability of exposure to this agent. These services include first aid, counselling and assessment of HIV risk, HIV testing after receiving informed consent and depending on the level of estimated risk, conducting a short course (28 days) of antiretroviral therapy (ART) to support and follow-up.
PEP is carried out:
• in case of occupational exposure to HIV or high probability of such exposure;
• in case of accidental exposure that is not connected with professional activities or with high probability of exposure, including that in hospitals.
The decision to implement PEP is to be taken based on clinical assessment of risk factors.
Occupational exposure to the risk of HIV infection
Occupational exposure to the risk of HIV infection involves exposure to blood or other potentially dangerous biological fluids due to their penetration under the skin, transfer on mucous membranes or on damaged skin that occurred in the performance of their duties. Occupational exposure is possible in healthcare workers and people of some other occupations (e.g., law enforcement, etc.). The danger of HIV exposure while on duty is posed by sharp instruments (e.g., needles) that are contaminated with blood or other potentially dangerous biological fluids, contacts through damaged skin (fissures, abrasions) or mucous membranes.
The risk of infection in case of occupational exposure depends on the exposure form and quantity of the hazardous material.
• In case of injury with a sharp instrument, the infection risk is on average about 0.23% (0.00-0.46%).
• The risk of infection in case of exposure to mucous membranes averages on about 0.09% (0.006-0.5%).
• Factors that increase the risk of infection:
• deep (intramuscular) injury;
• injuries where a contaminated instrument penetrates a blood vessel;
• injury with a hollow needle;
• high viral load (VL) in the person who is a likely source of infection.
• There are cases of infection through damaged skin described in literature. The average risk for this form of exposure has not been established precisely, but it is estimated as much lower than in case of exposure to mucous membranes.
• The risk of infection through contact with other body fluids or tissues has not been established either, however, it seems to be lower than in case of exposure to blood.
Biological fluids potentially dangerous in terms of the risk of HIV infection:
• Potentially dangerous fluids include blood and other body fluids containing visible admixture of blood.
• The risk of HIV transmission through cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluid is unknown.
• Semen and vaginal secretion do not play any role in HIV transmission from patients to medical staff.
• Faeces, discharge from the nasal cavity, saliva, sputum, sweat, tears, urine and vomiting are considered safe unless they contain visible impurities of blood.
Factors that influence the risk of HIV transmission after occupational exposure
• In case of exposure involving penetration through skin, the risk of HIV infection after exposure to blood of an infected person increases under the following conditions:
• visible blood on the tool (e.g., a needle);
• a needle or another sharp instrument enters a vein or artery, or in case of deep penetration.
• In addition, the risk of HIV transmission is increased in case of high levels of VL in the blood of the person who is a possible source of infection.
Exposure to the risk of HIV infection of non-occupational nature
Exposure to the risk of HIV infection of non-occupational nature implies any exposure to potentially hazardous biological fluids due to their penetration into the mucous membranes, under the skin or directly into a vein which took place outside the context of professional activities.
Exposure of non-occupational nature includes all random individual contacts with blood and other potentially dangerous biological fluids (semen, vaginal secretions, etc.) where there is a risk of HIV transmission. Such exposure includes unprotected sex; first of all sex accompanied by violence, damage or slippage of condoms; the use of common needles, syringes, utensils and solution for entering drugs by injectors; accidental needle pricks; bit wounds; exposure to mucous membranes, etc.
Exposure of non-occupational nature also includes nosocomial exposure to infection. Accidental HIV infection in the hospital may occur from a health worker or another patient.
Nosocomial infection with HIV may occur in three ways:
• from an HIV-positive healthcare worker who implements invasive intervention without knowing of his/her infection and/or failing to apply the standard safety equipment;
• during non-invasive intervention implemented by an HIV-positive healthcare worker (e.g., when s/he has nose bleeding or if a patient inflicts physical damage);
• occasional use for invasive intervention of a tool or material contaminated with HIV after it was used for another patient in case of non-compliance with standard procedures of preventing infection.
The risk of infection in case of one-time exposure to a source of HIV is generally estimated as low, but it may differ depending on the type of exposure:
Calculated risk of HIV infection in the various types of one-time exposure
Type of exposure – Risk, % to 10 000 contacts with the source of HIV
Blood transfusion 92.5
Transmission of HIV from mother to child 15-30
Using shared needles and syringes to inject drugs 0.8
Anal sex: passive partner 0.5
Injection through the skin 0.3
Contact with mucous membranes 0.1
Vaginal intercourse: women 0.01-0.15
Anal sex: active partner 0.065
Vaginal intercourse: men 0.05
Oral sex: passive partner 0.01
Oral sex: active partner 0.005
The risk of HIV infection through sexual violence may be higher than in voluntary sexual acts as trauma increases the risk of HIV transmission. The risk of infection also increases in case of STDs (in both active and passive partners), and of exposure of teenage girls to sexual violence (immature cells of the vagina and cervix increase the susceptibility to HIV infection).
In addition to sex-related exposure and that pertaining to injectable drug use, at times there are requests for PEP because of damage to the skin by used needles that are discarded in public places (such as parks or public transport). Although HIV infections as a result of such damage have not been documented, there is concern that syringes used by injectable drug users can be dangerous. However, such injuries are usually caused by needles with small cavities that contain only a small amount of blood and the viability of the virus, even if it is available, is rather uncertain. In the study of syringes used for administration of medicines to HIV-positive patients, HIV RNA was found only in 3.8%. (Rich JD, Dickinson BP, Carney JM, Fisher A, Heimer R. Detection of HIV-1 nucleic acid and HIV-1 antibodies in needles and syringes used for non-intravenous injection. AIDS 1998; 12:2345-50).
In a study of the viability of the virus in the needle, viable HIV was detected in 8% of needles after 3 weeks at room temperature; <1% contained the viable virus after 1 week storage at higher temperatures. (Abdala N, Reyes R, Carney JM, Heimer R. Survival of HIV-1 in syringes: effects of temperature during storage. Subst Use Misuse 2000; 35: 1369-83).
First aid after potential exposure to HIV
First aid after potential exposure to HIV involves actions to be performed immediately after the exposure. Their goal is to reduce the time of contact with infected body fluids (including blood) and tissues.
It is necessary to debride the place of exposure, thereby reducing the risk of infection.
In case of an injury with a needle or another sharp instrument, the procedure is as follows:
• Immediately wash the place of exposure with soap and water;
• Hold the damaged surface under running water (for several minutes or until bleeding has stopped) to allow blood to flow freely from the wound;
• In the absence of running water the damaged place should be debrided with a disinfectant gel or solution for washing hands.
• Do not use potent ingredients: alcohol, whitening liquids and iodine, as they may irritate the wounded surface and worsen the state of the wound;
• Do not compress or rub the damaged place;
• Do not suck the blood from the wound after the injection.
In case of spraying blood or other potentially dangerous biological fluids, the procedure is as follows:
When it is sprayed on intact skin:
• In the absence of running water, debride the damaged place with a disinfectant gel or solution for washing hands;
• Use a weak disinfectant, for example, 2% -4% chlorhexidine gluconate solution;
• Do not use potent ingredients: alcohol, whitening liquids and iodine, as they may irritate the wounded surface and worsen the state of the wound;
• Do not compress or rub the damaged place;
• Do not apply a bandage.
When it is sprayed in the eyes:
• Immediately rinse eyes with water or saline. Sit down, throw back your head and ask colleagues to gently pour water or saline solution on your eyes; for water or a solution to flow under the eyelids, the eyelids should be gently pulled up from time to time;
• Do not remove contact lenses during the rinsing because they create a protective barrier;
• Once the eye is rinsed, remove contact lenses and sanitize them as usual; after that they may be safely used.
• Do not wash your eyes with soap or disinfectant solution.
When it is sprayed on the mucous membrane of the oral cavity:
• Immediately spit out the liquid that got into the mouth;
• Thoroughly rinse the mouth with water or saline, and spit out again. Repeat rinsing several times.
• Do not use soap or disinfectant solution for washing.
It is necessary to implement HIV testing:
• of the person who may be a potential source of infection, whose blood or other biological fluids may be a potential source of infection (if possible), if they cannot be examined, it is necessary to examine the material the applicant was exposed to (blood, tissue, etc.). If the ELISA result cannot be obtained within 24-48 hours, it is recommended to conduct a rapid test for antibodies to HIV;
• of the person exposed to a potential source of HIV infection to determine whether it s/he was infected before the exposure.
it is also necessary to implement tests for antibodies to hepatitis C (anti-HCV) and surface antigen of hepatitis B (HBsAg).
Under no circumstances can PEP be delayed pending the test results to be estimated additionally for a person who underwent exposure, especially at high risk of infection!
Indications for PEP when dealing with occupation-related exposure:
• consulting in less than 72 hours after exposure; and
• it is known that the person in contact with hazardous material is not infected with HIV; and
• the person who is the source of the hazardous material is infected with HIV or the HIV status is unknown; and
• there was exposure to blood, body tissues, body fluids with visible blood impurities, concentrated virus, cerebrospinal fluid, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, or amniotic fluid; and
• there was exposure penetrating the skin with spontaneous bleeding or deep injection or spraying a large amount of fluid in the mucous membrane or prolonged exposure of damaged skin to hazardous material; and
• if there was penetration through the skin with a hollow needle that was just used or another sharp object with visible contamination with blood.
Indications for PEP to persons who experienced sexual violence:
• consulting in less than 72 hours after exposure; and
• it is known that the person who experienced violence is not infected with HIV; and
• the person who is the source of the hazardous material is infected with HIV or the HIV status is unknown; and
• risky exposure has been established, namely:
• receptive vaginal or anal sex without a condom or with a condom that slipped or was torn; or
• exposure of mucous membranes or damaged skin of the victim to blood or ejaculate of the rapist; or
• receptive oral sex with ejaculation; or
• the person who suffered sexual violence was under the influence of narcotics or was not conscious during the probable rape or is not sure about the nature of the contact; or
• the person suffered a gang rape.
In some cases there is no need for PEP, namely:
• a person who had a contact with a potential source of infection was HIV-positive before (which must be confirmed with documents);
• exposure to HIV is of permanent nature (contacts take place regularly rather than occasionally), for example, in sero-discordant couples (where only one partner is infected with HIV) if they use condoms only occasionally; or among IDUs who share one syringe;
• the exposure cannot result in infection (for example):
• if intact skin is exposed to potentially hazardous biological fluids;
• in case of a sexual contact with a condom which was not torn and did not slip during the intercourse;
• in case of exposure to safe body fluids (faeces, saliva, urine, sweat) that did not contain impurities of blood;
• in case of exposure to body fluids of a person whose blood is known to contain no antibodies to HIV, except for those who have high risk of recent infection and being in the ‘window period’ (seronegative period between infection and the appearance of antibodies to HIV – seroconversion);
• it has been over 72 hours since the exposure. PEP is already useless, however, the victim can be referred for counselling, testing and follow-up observation.
The time of beginning and duration of PEP
PEP should begin as soon as possible during the first hours after exposure without waiting for test results, optimally within 2 and no later than 72 hours after the exposure. The optimal duration of PEP is 28 days.
The choice of ARVs for PEP
For the PEP in case of both occupational and non-occupation exposure, including penetrating injuries with exposure of damaged skin and mucous membranes to infected material, the recommended scheme includes three antiretroviral (ARV) drugs (two nucleoside reverse transcriptase inhibitors – NRTIs, and one protease inhibitor – IP, which must be reinforced with ritonavir).
Information on medicated post-exposure HIV prophylaxis for 6 months in 2015
Information on medicated post-exposure HIV prophylaxis in 2014.