Chris Miller, PHD
The Centers for Disease Control and Prevention (CDC) reports updated information on health care workers (HCW) with documented and possible occupationally acquired AIDS/HIV infection (CDC: HIV/AIDS Surveillance Report. 1997, 9[No. 2]: 1-43). The data presented are the most current and are based on information reported through December 1997 in the United States.
Documented occupational transmission of HIV has been reported in 54 health care workers, none of which are dental workers. This has increased from 52 since December 1996, and includes:
- 22 nurses
- 19 laboratory technicians
- Six physicians
- Three hospital technicians
- One embalmer, health aide, housekeeper, and therapist
A documented transmission is defined as:
- having an exposure involving an HIV-positive patient.
- testing HIV-negative at the time of exposure.
- seroconverting to HIV-positive.
- having no identifiable behavior or transfusion risks.
Of these 54 health care workers, 46 had percutaneous (through the skin) exposures; five had mucocutaneous exposures (sprays or splashes involving mucous membranes); two had both percutaneous and mucocutaneous exposures; and one had an unknown route of exposure. Thus, sharp injuries through the skin were the most numerous routes of exposure. Of these 54 cases, 49 had contact with the patient`s blood; one with visibly bloody fluid; one with an unspecified fluid; and three with a concentrated virus in a laboratory. Twenty-five of the health care workers have progressed from being infected with HIV to AIDS.
Possible occupational transmission of HIV has been reported in 132 health care workers. The types of health care workers involved are:
- 32 nurses
- 18 laboratory technicians
- 17 physicians (11 nonsurgical and six surgical)
- 15 health aides
- 12 emergency medical technicians or paramedics
- 10 housekeepers or maintenance workers
- Nine technicians or therapists other than those listed
- Seven dental workers
- Three dialysis technicians
- Two each of embalmers, respiratory therapists, and surgical technicians
- Three other health care occupations
A "possible" transmission is defined as:
- having a percutaneous or mucocutaneous exposure involving an HIV-positive patient.
- seroconverting to HIV-positive.
- having no identifiable behavioral or transfusion risks.
The reason for listing these cases as "possible" is because the HIV statuses of the exposed health care workers was not known at the time of exposure - since they were not tested at that time. Thus, there is an outside chance that the health care workers may have already been HIV-positive at the time of occupational exposure.
The previous edition of the CDC report listed 111 "possible" cases, but the increase to 132 in the current report does not indicate a recent increase in the trend of possible occupational transmission. Instead, additional cases of health care workers with AIDS and without behavioral or transfusion risks were found and added to the "possible" occupational transmission category. This occurred as a result of a specific review by the CDC of AIDS cases without identifiable behavioral or transfusion risks. Most of these added cases were diagnosed with AIDS more than five years ago.
Since there have been no documented cases of occupational HIV disease in dental workers and only seven dental workers are suspected of having acquired a possible occupational transmission, the risk for occupational transmission of HIV is low for dental workers. However, this risk is not zero. The key prevention procedures are carefully handling contaminated sharps and routinely wearing appropriate barriers to avoid contact with sprays or spatter of oral fluids. Sharps are any items that may puncture the skin including scalers and all other pointed or sharp instruments - needles, wire, files, scalpel blades, burs, etc.
Preventive procedures for hygienists, assistants, and dentists to consider include:
- Making sure all those who are to handle sharps have been properly trained to do so safely.
- Adding enough extra sterile, sharp scalers to the instrument setup to avoid having to sharpen contaminated scalers at chairside.
- Stabilizing the sharpening stone on a counter and sharpening with one hand or using a rotary sharpening device.
- Using the proper hand/finger positioning when using sharp instruments in the mouth.
- Replacing hand-scrubbing with ultrasonics or washer-disinfect action for cleaning of contaminated instruments.
- Pointing the bur away form you when placing a high-speed handpiece back into its holder.
- Recapping needles using a safe, one-handed technique or a special cap-holding device.
- Disposing of sharps in proper containers as soon as possible after use and avoiding a second or third handling of the item.
- Using sharps containers that will not easily tip over, placing these containers where sharps are used or may be found, filling them only three-fourths full, closing them before moving them, and disposing of them properly.
- Slowing down and never being in a hurry when handling a contaminated sharp.
- Watching what you`re doing when intensive care patients. In the Preventive Dentistry Clinic at State University of New York in Buffalo, patients who had been treated for periodontal disease, including with antibiotics, had potential respiratory pathogens in their mouths.
In a recent study of nursing home patients, 72 percent had poor oral hygiene. A link between poor oral hygiene and the incidence of pneumonia in nursing homes has been suggested, but very little supporting evidence is available at this time. A preliminary report of a longitudinal study on nursing home patients does show an association between dental status and development of aspirating pneumonia.
Nursing educators have suggested giving at-risk patients antibiotic lozenges which would selectively decontaminate the digestive tract. A study comparing antibiotic and placebo lozenges demonstrated a significant reduction in the incidence of pneumonia: 16 percent versus 78 percent.
If antibiotics work, would chlorhexidine work? Probably not as effectively, say Drs. Frank Scannapieco and Joseph Mylotte, authors of a report in a 1996 issue of the Journal of Periodontology. Although chlorhexidine can inhibit bacterial growth, it may not be effective against the Gram-negative species associated with pneumonia. Effective oral hygiene may be the best way to reduce the risk of hospital-acquired aspiration pneumonia.
In light of the many reports linking periodontal status with systemic conditions, the American Academy of Periodontology has launched a national public awareness campaign, including a toll-free consumer information number: (800) 356-7736. They have also created an interactive Web site (www. perio.org). We will be seeing and hearing more about the possible links between oral and systemic health both from the profession and from our patients. Be prepared.
Chris Miller is director of Infection Control Research and Services and professor of oral biology at Indiana University.