Occupational Transmission of HIV: Health Care Workers

There is a small, but definite, occupational risks of HIV transmission to health care workers in hospitals, laboratories and other places, who work with HIV containing materials, particularly when sharp objects like needles, are used. Few million health care workers are stuck with needles or other sharp medical instruments throughout the world every year.

Health care worker are at potential risk of HIV infection through contact of mucous membrane or non intact skin like exposed skin that is chapped, abraded, or afflicted with dermatitis or ulcer, with blood, tissue etc. or other potentially infectious body fluids, or percutaneous injuries like a needle prick or cut with a sharp object/instrument. Multi institutional studies have indicated that the risk of HIV transmission following skin puncture from a needle or a sharp object that was contaminated with blood from a person with documented HIV infection is about 0.3% and after a mucous membrane exposure it is 0.09%. HIV transmission after non intact skin exposure is seen but it is not clear what percentage of these exposures lead to infection. But it is estimated to be much less than other two mentioned above. Transmission of HIV through intact skin does not occur. The following fluids are also considered potentially infectious: cerebrospinal fluid, synovial fluid, amniotic fluid pleural fluid, peritoneal fluid, and pericardial fluid. Feces, saliva, sputum, sweat, nasal secretions tears, urine, and vomits are not considered potentially infectious. Semen and vaginal secretions are also considered potentially infectious, but have not been implicated in occupational transmission from patients to health care workers. There are rare cases of HIV infection through human bite though not considered as occupational hazard.

An increased risk for HIV infection following percutaneous exposures to HIV infected blood is due to exposures involving a relatively large quantity of blood. As the procedure involves a needle placed directly in a vein or artery, or a deep injury. Mucocutaneous transmission of HIV includes exposure to an unusually large volume of blood, and a prolonged contact. The risk increases for exposures to blood from patients with advanced-stage disease, because of the higher titer of HIV in the blood as well as to other factors, such as the presence of more virulent strains (capable of causing disease with lesser amount) of virus.

The use of antiretroviral (anti HIV) drugs as post exposure prophylaxis decreases the risk of infection. The risk of hepatitis B virus (HBV) infection following a similar type of exposure is about 6% to 30% in non immune individuals; if a susceptible worker is exposed to HBV, post exposure prophylaxis with hepatitis B immune globulin and initiation of hepatitis B vaccine is more than 90% effective in preventing HBV infection.

There have been at least three reported instances in which transmission of infection from a health care worker to patient has occurred. Non compliance of infection control and the reuse of contaminated syringes have resulted in the transmission of HIV from patient to patient in hospitals, nursing homes, and outpatient settings. Transmission of HIV through health care worker occurs; the health care worker may or may not be HIV positive.

The very rare occurrence of transmission of HIV as well as hepatitis B and hepatitis C to and from health care workers in the workplace, shows the importance of the use of universal precautions when caring for all patients.