Prevention of HIV and hepatitis C infection

Viral hepatitis and HIV infection have become one of the main health problems both in our country and in most countries of the world. Almost a third of the world's population is infected with the hepatitis B virus, and more than 150 million are carriers of the hepatitis C virus. In the Russian Federation, this figure ranges from 3 to 5 million people. Every year, 1.5-2 million people die from pathologies associated with viral hepatitis, including liver cirrhosis and hepatocellular carcinoma. According to WHO forecasts, chronic hepatitis C will become a major health problem in the next 10-20 years. As a result of its widespread distribution, the number of patients with liver cirrhosis may increase by 60%, with liver carcinoma by 68%, with decompensated liver damage by 28%, and mortality from liver diseases will increase by 2 times. In Moscow, according to 2006 data, the infectious diseases that most often lead to death are viral hepatitis, HIV infection, and tuberculosis.

Even with the use of the entire arsenal of modern therapeutic agents, a fatal outcome in acute hepatitis B is possible in 0.3-0.7% of cases; in 5-10% of patients, chronic forms develop, cirrhosis or primary liver cancer develops in 10-20% of them. Viral hepatitis C is characterized by an asymptomatic course, so the disease rarely comes to the attention of doctors, but patients pose a serious threat to others, being the main source of infection. Hepatitis C is characterized by an unusually high frequency of chronic course of the process, leading to serious consequences. For one icteric case of acute viral hepatitis C, there are six cases of asymptomatic course. Most patients develop chronic forms of the disease, in 40% of patients - leading to the development of cirrhosis, and later in a third of them primary liver cancer develops. For its quiet but insidious "nature" hepatitis C is called a "gentle killer".

The HIV pandemic also continues to grow. Currently, according to WHO and UNAIDS, 66 million people in the world are infected with HIV, of whom 24 million have already died from AIDS. In Russia, at the end of 2006, the total number of recorded cases of HIV infection since the first one was registered in 1987 was 391,610 people, of whom about 8 thousand are no longer alive. The number of patients increases every year. HIV infection is characterized by a long and almost imperceptible course for many years after infection, leading to a gradual depletion of the body's defenses, and after 8-10 years - to the development of AIDS and life-threatening opportunistic infections. Without antiretroviral treatment, an AIDS patient dies within a year.

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Routes of transmission of HIV and hepatitis C

Potentially dangerous biological fluids that most often transmit viral infections include blood, sperm, vaginal secretions, and saliva. Viruses can be found in cerebrospinal, pericardial, synovial, pleural, peritoneal, amniotic, and other biological fluids contaminated with the blood of infected patients (urine, vomit, sputum, sweat, and tears). Blood products can be a rare source of viral infections.

The virus can be transmitted when any of the listed fluids enters the blood through damaged skin or mucous membranes, or when splashes come into contact with the conjunctiva of the eye.

In recent years, the epidemic process of viral hepatitis has involved the majority of injection drug users. Infection occurs through the shared use of syringes, which maintains a high incidence rate. The sharp increase in the number of HIV carriers at the end of the last century is also associated with the use of psychotropic drugs intravenously. The current stage of the HIV epidemic is characterized by predominantly sexual transmission of the virus. In recent years, the overwhelming majority of those infected and died from AIDS in the world are not homosexuals and drug addicts, but people with heterosexual sexual behavior who do not use drugs.

Nosocomial transmission of HIV and hepatitis C

Infection of patients with viral hepatitis in medical institutions is becoming a serious problem, accounting for 3-11% of the total number of infected. These viruses are transmitted most intensively in surgical departments with long-term stay of patients who underwent abdominal interventions and various invasive procedures, as well as manipulations with violation of the integrity of the skin; in departments where disinfection and sterilization of instruments and equipment is difficult (hemodialysis, hematology, resuscitation and endoscopy departments).

Patients can also become infected through contact with the blood of an infected health care worker. In 1990, a story emerged in which an HIV-infected dentist infected one of his patients in Florida during oral surgery. The dentist was later found to have infected six more patients. The earliest case of hepatitis B virus transmission from a health care worker to a patient was reported in 1972, when a nurse infected eleven patients.

Evidence from analyses of HIV and hepatitis B cases suggests that the risk of infection increases with high levels of viremia, as demonstrated by either a high 'viral load' in the case of HIV or the presence of hepatitis B E antigen (HBEAg).

HIV and Hepatitis C Infection in Healthcare Workers

In Western Europe, about 18,000 employees of medical institutions contract the hepatitis B virus annually (an average of 50 people per day). In Moscow in 2001, viral hepatitis was registered in 3% of medical workers. The overall level of HIV infection among medical workers is from 0.4 to 0.7%.

Infection with the hepatitis B virus is becoming a serious occupational hazard. Among medical personnel in the United States, who frequently come into contact with patient blood, the infection rate is 15-33%, while for the rest of the population the rate does not exceed 5%.

In Moscow in 1994, before the start of a broad program of hepatitis B vaccination, the incidence rates among health workers were 3-3.5 times higher than among adult city residents. An even more serious situation was observed in the Moscow Region, where the average incidence rate of hepatitis B among health workers was 6.6 times higher than among the rest of the population. A similar situation was in many regions of our country. Only with the start of broad vaccination against hepatitis B among health workers did these rates begin to decrease. However, in the event of violation of safety regulations or emergency situations, a high risk of occupational infection of unvaccinated hospital and clinic employees remains.

In recent years, the incidence of hepatitis C among health care workers has increased significantly. According to various studies, the prevalence of hepatitis C among health care workers in the United States ranges from 1.4 to 2%, which is comparable to the general situation.

The high risk of hepatitis and HIV infection among healthcare workers is associated with frequent and close contact with blood. In the United States, 2,100 of the 8 million healthcare workers receive an accidental injection or other skin microtrauma every day during work, resulting in hepatitis in 2 to 4% of workers. Almost every day, one healthcare worker dies due to decompensated cirrhosis or primary liver cancer.

Skin damage most often occurs when using needles during or after medical procedures. The risk of skin damage is especially high when disassembling an intravenous infusion system, securing a needle in a vein, removing it, drawing blood, putting a tip on a needle, and changing bed linen.

The risk of contracting various viral infections through contact with contaminated blood varies. It is believed that the probability of contracting hepatitis C is lower than hepatitis B. This is due to the fact that a larger amount of infected blood must enter the body to become infected with hepatitis C. The risk of infection of health care workers who receive accidental injuries from injection needles with the hepatitis C virus is from 5 to 10%. One case of transmission of the hepatitis C virus with drops of blood that got on the conjunctiva is known. According to the US Centers for Disease Control and Prevention (CDC) in 1989, the frequency of transmission of the hepatitis B virus to health care workers after contact of damaged skin with HBEAg-positive blood of a patient is approximately 30%, and with similar contact with HIV-infected blood - 0.3%.

The highest rates of hepatitis B are observed among resuscitators and surgeons. They are twice as likely as employees of other departments to have HBsAg and antibodies to the hepatitis C virus. The highest risk groups also include personnel of blood service institutions, hemodialysis departments, kidney transplantation and cardiovascular surgery.

A study conducted in Germany and Italy among various groups of medical workers showed that the risk of infection of operating room medical personnel increases with increasing length of service: the minimum number of infections occurs in the first 5 years of work, and the maximum - in 7-12 years. The group at greatest risk is nurses (almost 50% of all cases), followed by doctors - 12.6%. Laboratory personnel, orderlies and nurses are at significant risk. There are now good reasons to consider hepatitis B and C as occupational diseases of doctors.

By now, there have also been many confirmed cases of occupational HIV infection among health care workers. In 1993, 64 cases were documented: 37 in the USA, 4 in Great Britain, 23 in Italy, France, Spain, Australia and Belgium. In 1996, the Centers for Disease Control and Prevention (Atlanta, USA) published a report on 52 cases of proven HIV infection among health care workers at work, including 19 laboratory workers, 21 nurses, 6 doctors and 6 other specialists. In addition, another 111 cases of possible occupational infection were reported. Almost all of them are associated with needle sticks while providing care to patients. In Russia, about 300 HIV-infected health care workers have been identified, but they were infected either sexually or by injecting drugs with a non-sterile syringe. There are only two documented cases of infection of health care personnel during work.

Those at the highest risk of HIV infection are healthcare workers who provide care to HIV-infected patients:

• mid-level medical personnel, primarily procedural nurses;
• operating surgeons and operating nurses;
• obstetricians-gynecologists;
• pathologists.

The risk of HIV infection depends on the degree of damage to the integrity of the skin and mucous membranes. The risk of infection is greater the more extensive and deep the skin contact (injections and cuts). If the integrity of tissues is damaged, the risk of infection of medical personnel is about 0.3%; if HIV-infected blood gets on the mucous membranes, the risk is even lower - 0.09%, and if intact skin comes into contact with blood, the risk is practically zero.

A needle prick after taking blood from a patient's vein is more dangerous than a prick after an intramuscular injection. The risk also depends on the stage of the disease: in the acute stage of HIV infection, as well as in the late stages (AIDS), when the level of viremia is high, the danger is greatest. If the patient is receiving antiretroviral therapy, its duration is important, since during treatment there is a gradual decrease in the viral load (the content of the virus in the blood); the risk of infection from such a patient is reduced. In some cases, the presence of resistant strains of HIV in the patient is important for post-exposure prophylaxis.

Factors that determine the risk of HIV infection among medical personnel:

• degree of tissue integrity violation;
• degree of contamination of the instrument;
• the stage of HIV infection in the patient;
• the patient receiving antiretroviral therapy;
• the presence of resistant strains of HIV in the patient.

Prevention of nosocomial and occupational transmission of HIV and hepatitis C

Preventive measures should be aimed at preventing the intra-hospital spread of infection and professional infection of healthcare workers.

Early in the HIV pandemic, it was recognized that the condition of patients and blood samples encountered by health care workers was presumably unknown. This led to the recommendation to extend the concept of “blood and body fluid precautions” to all patients. The concept is known as universal precautions (CDC, 1987). Its application eliminates the need for mandatory prompt identification of patients with bloodborne infections and requires treating every patient as a potential source of infection. Universal precautions include hand washing, use of protective barriers for potential exposure to blood, and caution when using needles and other sharp instruments in all health care settings. Instruments and other reusable equipment used in invasive procedures should be appropriately disinfected or sterilized. Subsequently, recommendations were developed to prevent the transmission of HIV and viral hepatitis through occupational contacts, including provisions for vaccination against viral hepatitis B, for the prevention of infection in dentistry and in the work of emergency medical teams, for the use of post-exposure chemoprophylaxis when HIV infection is suspected, and for the prevention of HIV transmission from health care workers to patients during invasive procedures (CDC, 1990, 1991, 1993).

Ways to reduce the risk of infection of medical personnel

To reduce the risk of infection of medical personnel in medical and preventive institutions, it is recommended:

• regular informing and training of health workers on methods of prevention when in contact with potentially infectious material;
• prevention of medical and technical workers with damaged skin (wounds, cracks, weeping dermatitis) from working with patients of any profile, biomaterials and objects contaminated with them;
• providing all workplaces with disinfectant solutions and a standard first aid kit for emergency prevention;
• proper collection and processing of infected material, including various biological fluids, used instruments and dirty linen;
• use of personal protective equipment: gloves, glasses, masks, aprons and other protective clothing;
• vaccination against hepatitis B of all healthcare workers, primarily those at professional risk;
• regular screening of all personnel for hepatitis and HIV viruses (before and during work);
• strict administrative control over the implementation of the prevention program.

Actions to prevent infection of medical personnel with viral hepatitis and HIV infection:

• attend classes on the prevention of parenterally transmitted infections and follow the relevant recommendations;
• plan your actions in advance before any work with hazardous tools, including their disposal;
• do not use dangerous medical instruments if they can be replaced with safe ones;
• do not recap used needles;
• promptly dispose of used needles in a special puncture-proof waste container;
• promptly report all cases of injury when working with needles and other sharp objects and infected substrates in order to promptly receive medical assistance and carry out chemoprophylaxis of infection;
• inform the administration of all factors that increase the risk of injury in the workplace;
• give preference to devices with protective devices;
• to train health workers at all levels: managers, doctors, nurses, social workers, consultants and other specialists;
• provide complete and accurate information on infection transmission and risk factors;
• teach methods to combat discrimination and stigma;
• maintain confidentiality.

Vaccination of health workers against hepatitis B. For vaccination, one of the following two schemes is used:

• 0, 1, 6 months (administration of the second and third dose, respectively, 1 and 6 months after the first dose);
• 0, 1, 2 and 6 months (administration of the second, third and fourth dose, respectively, 1, 2 and 6 months after the first dose).

The second regimen is recommended if, due to a high degree of risk, it is necessary to quickly provide protection against a possible infection. In such cases, emergency prevention is based on the ability of vaccines to quickly trigger the mechanism of specific immunity development and thus prevent the development of the disease, provided that the vaccine is administered early after infection. In an emergency, it is necessary to administer specific immunoglobulin (HBsIg) containing antibodies to HBsAg (anti-HB5) in high concentration intramuscularly on the first day (but not later than 48 hours), 0.12 ml (at least 5 IU) per 1 kg of body weight. The first dose of the vaccine is administered simultaneously. Vaccination is then continued according to the second regimen. The full vaccination course is carried out if the absence of viral hepatitis markers in the victim is detected during the blood test taken before the vaccine administration. It is believed that it is advisable to start vaccinating medical workers against hepatitis B even before they start working independently (in the first years of medical institutes and colleges). Vaccination protects the medical worker and eliminates the possibility of transmitting the infection to the patient.

Currently, an accelerated immunization schedule with the EngerixB vaccine has been officially registered for the prevention of viral hepatitis B. The schedule is 0-7-21 days, it is used in a number of hospitals for patients with upcoming planned surgical interventions and other patients with planned invasive manipulations. The introduction of the vaccine according to this schedule leads to the formation of anti-HB3 in a protective concentration in 81% of vaccinated people, however, after 12 months, an additional vaccine is required.

An anti-HB5 titer of 10 mIU/ml is an indicator of the formation of protective immunity, which develops in more than 95% of vaccinated individuals and provides protection against infection not only with hepatitis B, but also with delta hepatitis (the hepatitis D virus requires the presence of the hepatitis B virus for its replication, since it infects a person only together with the hepatitis B virus. This can increase the severity of liver damage).

If the antibody titer is less than 10 mIU/ml, the person remains unprotected from infection and a second vaccination is necessary. In some individuals, even a second vaccination may be ineffective. Healthcare workers with no protective level of anti-HB5 must strictly follow safety regulations in the workplace.

To prevent infection with the hepatitis C virus, it is necessary to follow universal precautions and prevent skin lesions, since there is no specific vaccine yet.

Post-exposure prophylaxis of HIV infection

The main way to protect the health of medical workers in an emergency with the risk of HIV infection is preventive measures, including the administration of antiretroviral drugs. In the event of an emergency, it is recommended:

• If the skin is damaged (cut, prick) and bleeding appears from the damaged surface, it is not necessary to stop it for several seconds. If there is no bleeding, then the blood should be squeezed out, the skin should be treated with a 70% alcohol solution, and then with a 5% iodine solution.
• If infected material comes into contact with the face or other exposed areas of the body:
  • wash the skin thoroughly with soap, then wipe with a 70% alcohol solution;
  • rinse eyes with water or 0.01% potassium permanganate solution;
  • If contaminated material gets into your mouth, rinse your mouth with a 70% alcohol solution (do not drink!).
• If contaminated or suspicious material comes into contact with clothing:
  • immediately treat this part of the clothing with one of the disinfectant solutions;
  • disinfect gloves;
  • take off the robe and soak it in one of the solutions;
  • Place clothes in sterilization boxes for autoclaving;
  • wipe the skin of your hands and other areas of the body under contaminated clothing with a 70% alcohol solution;
  • Wipe shoes twice with a rag soaked in a solution of one of the disinfectants.
• If infected material gets on the floor, walls, furniture, equipment and other surrounding objects:
  • pour any disinfectant solution over the contaminated area;
  • wipe after 30 minutes.

Chemoprophylaxis of parenteral transmission of HIV. In case of a threat of parenteral infection - damage to the skin with an instrument infected with HIV, contact of material containing HIV with mucous membranes or damaged skin - chemoprophylaxis with antiretroviral drugs is recommended. The following chemoprophylaxis regimen has been proven to be effective (the risk of infection is reduced by 79%): zidovudine - taken orally at 0.2 g 3 times a day for 4 weeks.

Currently, other regimens are used depending on the availability of antiretroviral drugs in medical institutions. Efavirenz - 0.6 g per day + zidovudine - 0.3 g 2 times a day + lamivudine 0.15 g 2 times a day. If intolerance to one of the drugs develops, it is replaced in accordance with the general rules described in the guidelines for antiretroviral therapy of patients with HIV infection. In addition, any regimens of highly active antiretroviral therapy can be used depending on the specific availability of antiretroviral drugs in a medical institution, with the exception of regimens using nevirapine, since its use increases the risk of side effects that threaten the lives of people with normal immunity. A single dose of nevirapine followed by a switch to another regimen is acceptable in the absence of other drugs.

It is very important to start chemoprophylaxis as early as possible, preferably within the first two hours after possible infection. If it is not possible to start it immediately according to the high-intensity therapy scheme, then it is necessary to start taking the available antiretroviral drugs as soon as possible. After 72 hours after possible infection, it is pointless to start chemoprophylaxis or expand its schemes.

Recommendations for chemoprophylaxis can be obtained from a specialist at the AIDS Center by phone. At night, on weekends and holidays, the decision to start antiretroviral therapy is made by the doctor in charge of the hospital.

Registration of emergency situations is carried out in accordance with the laws and regulations adopted by the Federal Government and the subjects of the Federation. When registering an accident, the date and time of the incident, the full name of the health worker, his position are recorded in a special journal; the manipulation during which the accident occurred and the measures taken to protect the health worker are indicated. The full name, age, address of the patient, during the provision of assistance to whom the accident occurred, are separately indicated; information about HIV infection (HIV status, stage of the disease, received antiretroviral therapy, HIV RNA level (viral load), the number of CD4 and CD8 lymphocytes) and the presence of viral hepatitis B and C are entered in detail. If the source patient or his HIV status are unknown, a decision is made to begin post-exposure prophylaxis based on the probable risk of infection.

The fact of injury should be immediately reported to the head of the department or his deputy, as well as to the AIDS Center and the State Sanitary and Epidemiological Surveillance Center (SSES). Each medical and preventive institution should have a record of injuries sustained by medical workers and registered as an industrial accident.

Observation of affected employees

A healthcare worker must be monitored for at least 12 months after an emergency contact with a source of infection. Laboratory testing of the victim for HIV antibodies is carried out when an emergency situation is identified, 3, 6 and 12 months later. The victim must be warned that he must take precautions throughout the entire observation period to avoid possible transmission of HIV to another person.

Following the above-mentioned case in Florida, when a dentist infected his patients with HIV, relevant documents were developed on the prevention of infection with pathogens transmitted by blood from medical workers. Currently, such documents have legislative force in a number of countries, where committees have been formed to manage medical workers infected with hepatitis or HIV and on their professional employment. In 1991, the US Centers for Disease Control and Prevention published recommendations on the prevention of transmission of HIV and hepatitis B to patients during invasive procedures. Procedures with a high probability of transmitting the viral infection were listed. It was recommended that infected medical workers be removed from performing such procedures (except in certain situations). However, in the US, there are still no restrictions on the professional activities of medical workers infected with the hepatitis C virus.