HIV exposure and treatment

Occupational HIV exposure of health-care providers is quite common, but not all exposures lead to infection. This is the risk that every health worker must face.

Dr. Nguyen Tan Thu with many years working in the field of HIV prevention and treatment said, in fact, occupational exposures by health workers are quite common, but not all cases of exposure. leads to infection. This is considered to be a risk that every health worker must face during his or her stay.

In fact, occupational exposures by health workers are quite common.(Artwork: HIV).

Exposure to HIV (exposure) is understood as a situation where contact with secretions is likely to carry HIV. A situation that is considered at risk of exposure must satisfy two factors:

1. The most common infectious secretions are blood, vaginal fluids, semen and breast milk. Other common body fluids such as sweat, tears, saliva, urine . are considered to be no risk of infection.
2. Input factor: Open wound, skin piercing, mucosal contact (eyes, nose, mouth, vagina, anus .).

Due to the silky and unrecognizable nature of the disease, all exposure to secretions of people who are unaware of anti-HIV serological status are considered ' potentially pathogenic '. Thus, situations where the source of exposure cannot be verified such as being stabbed in a public place, the partner suddenly . is considered as the case of contact with secretions of a positive person.

Exposure in the community mainly revolves around 2 situations. The first is sexual exposure when sex does not use a condom or a condom is broken or torn, raped. The second is exposure to the blood due to a needle-piercing wound or sharp objects thrown into public areas and visible blood.

Meanwhile, occupational exposures in health workers are much more diverse. Particularly their work must be exposed to a variety of more dangerous secretions (amniotic fluid, cerebrospinal fluid, pus, pleural fluid, peritoneal fluid). At the same time, they have a higher frequency of exposure through procedures such as visits, injections, perfusion, aspiration, surgery . so the risk of exposure is higher.

According to the US Department of Disease Management, an estimated 380,000 cases of health workers in hospitals are stabbed annually. That's not to mention other types of exposures and exposure cases in non-hospital settings. In Vietnam, situations of doctors who give birth to pregnant women to the extent that the amniotic fluid is wet with clothes, the emergency times that the patient's blood is shot all over are not uncommon. While the probability of health workers having a chance to interact with a positive patient is much higher than the general population.

Exposure is a necessary condition to lead to infection, but not a sufficient condition. For example, a family with someone with the flu. In this activity, the whole family will be more or less exposed to the pathogen. This situation is understood to mean they are exposed to flu germs. However, not all members of this family will get the flu, depending on each person's exposure and health.

The situation is similar for exposure and HIV infection . Factors such as transmission, the number of HIV viruses in their exposed and immune secretions each affect their ability to switch from exposure to infection.

The Centers for Disease Control and Prevention (CDC) estimates that the risk of one-time exposure to HIV from the skin piercing needle is about 0.3%, blood cord to the open wound or the knife lining. Dynamic from 0.1 to 0.3%, through sexual intercourse ranged from 0.1 to 0.5%. Thus, with one exposure, the risk of HIV infection is not high. If compared with blood-borne diseases such as hepatitis B, it is only 1/100 and 1/10 of hepatitis C.

Occupational exposures in health workers are much more diverse.

Post-exposure prophylaxis

Along with the development of antiretroviral therapy with antiretroviral drugs , the researchers succeeded in developing and applying post-exposure prophylaxis (Post-exposure prophylaxis - PEP). This is a medical intervention based on the ability of ARV to inhibit HIV.

Information on primary HIV infection indicates that systemic HIV infection does not occur immediately but there is a short delay between the time of exposure to the virus and the occurrence of HIV in the blood. During this 'window of opportunity ', antiretroviral therapy can prevent systemic infection, thereby helping the person avoid 'chronic HIV infection'.

The experimental model of the SIV viral pathogen, HIV relative, causes disease in monkeys, indicating that, after exposure to HIV, immune cells in place of HIV are infected. within the first 24 hours. Infected cells move to adjacent lymph nodes over the next 24-48 hours. In 5 days, HIV can be detected in the blood.

Thus, if using ARV soon after exposure can prevent systemic infection by preventing the replication of HIV in a few infected cells initially. After maintaining ARV in the body for 4 weeks, initially infected cells will be eliminated by the body due to cellular immunity, resulting in complete elimination of HIV from the body.

A case-control study in 1997 found that the effectiveness of PEP treatment helped reduce the risk of infection by 81% if Zidovudine was used. Thereafter, PEP treatment was gradually improved to improve efficiency. WHO is guiding the use of 2-drug regimens or 3 drugs, thereby increasing the success rate up to 95-99%. The effectiveness of treatment will be highest in the first few hours after exposure, gradually decreasing over time and is thought to be ineffective after 72 hours from exposure.

Post-exposure treatment, PEP treatment includes:

Step 1: Handle the wound in place

1. For skin damage leading to bleeding : Immediately flush the wound under running water. Allow the wound to bleed itself for a short time without squeezing. Wash thoroughly with soap and clean water, then disinfect with antiseptic solutions (Dakin, Javel 1/10, or 700 alcohol) for at least 5 minutes.
2. In case of exposure through eye mucosa: Wash eyes with distilled water or NaCl 0.9% salt continuously for 5 minutes.
3. Oral, nasal exposures: Wash, small nose with distilled water or NaCl 0.9% solution. Rinse mouth with NaCl 0.9% solution many times.

Step 2 : Report the person in charge and make a report. Notice clearly the date, time, circumstances, and injury assessment, the level of risk of exposure.

Step 3: Assess the risk of exposure according to the depth of vulnerability of the lesion and the area of ​​contact.

Step 4: Determine the HIV status of the source causing the exposure. Usually, health workers will advise those who are exposed to participate in HIV testing. In situations where this person is already aware of the infection status, it is necessary to gather information regarding their ARV treatment.

Step 5: Determine the HIV status of the exposed person by testing.

Step 6: Advise the exposed person about the risk of infection, post-exposure prophylaxis, medication and side effects, follow-up procedure .

Step 7: Preventive treatment with ARV drugs continuously for 4 weeks. All risk exposures should be prescribed ARV treatment as soon as possible, 2-6 hours from exposure and no more than 72 hours. In parallel with assessing the HIV status of the source of exposure and the person exposed, depending on the situation, the doctor can continue treatment for a full 4 weeks or discontinue antiretroviral therapy as appropriate.

ARV drugs.

Step 8: Follow up with test test after one month, 3 months and 6 months. On the community level, when there is exposure, it is necessary to quickly perform on-site wound management (if any) according to the instructions in step 1. Next, it is necessary to quickly approach the medical facility with HIV infection. (such as Tropical Diseases Hospital, provincial level general hospital, community consultation department). If information is obtained from the source of exposure, pay attention to their ARV treatment regimen. The remaining steps of the process will be supported by the facility's medical staff.

Factors affecting the effectiveness of PEP treatment include:

1. Delay in access to ARV. As recommended by the WHO, the first dose of ARV should be used as soon as possible, within the first few hours, possibly before an HIV screening test result is available. The slower the ARV approach is, the more effective the prevention is.
2. Antiretroviral drug resistance of the source of exposure, therefore, the best PEP treatment regimen needs to be adjusted to suit the regimen that the patient is using (it is recommended that the drug is different from the patient's medication). . The preferred regimen was also adapted to accommodate the prevalence of ARV resistance in the population. In Vietnam, the rate of drug resistance regimen 1 is still low, so the preferred regimen is still the first regimen for unknown cases of ARV regimens of the source of exposure.
3. Compliance of exposed persons: ARV compliance is required during 4 weeks of treatment as well as post-treatment follow-up procedures.

Note:

1. Post-exposure prophylaxis should only be used in unexpected accident situations, not as a long-term preventive measure.
2. When exposure occurs, psychological comfort is an essential factor. Comfort psychology helps the body better respond to drugs, limit the effects and side effects of ARV on life and activities.

In fact, it is very rare to record any seroconversion from negative to positive after PEP treatment. Although the protection effect is not 100%, experts in the field claim this is an important spearhead in repelling the HIV epidemic.

It is recommended that the management of exposures in the community is generally the management of one's own risk behaviors. Health care exposure management is combined into steps in the universal prevention process. In which, the main criterion is to see that all secretions are dangerous secretions and have careful attitude in contact.Protective barriers should be used : glasses, protective gowns, medical masks, gloves. Clean hands before and after handling. Practice safe injection. Environmental control of blood and body fluids through cleaning of rooms, cleaning and management of infected blood and epidemics. Handling sharp objects such as needle heads, cutlery .