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Scientific world belatedly recognizes HIV risks to laboratorians.

Once mere speculation, many trends in occupational HIV transmission are now supported by hard data. Among workers newly in the spotlight: clinical laboratorians.

AS USUAL, the annual AIDS conference, held in Amsterdam from July 19 through 24 of this year, was embroiled in controversy. Originally scheduled to convene in Boston, the meeting was moved to the Netherlands at the last minute after U.S. officials failed to relax travel restrictions on HIV-infected individuals. A noticeable anti-U.S. Government attitude pervaded the meeting.

An assortment of new issues was brought to the table, including the discovery of a new virus, new vaccine strategies, new but disappointing developments in AIDS treatment, new animal models, and attempts to provide a new definition of AIDS. Also discussed were gene therapy, human rights, and the growing proportion of women with AIDS.

Michael H. Merson, M.D., director of the Global Programme on AIDS, World Health Organization (WHO), opened the conference by announcing these sobering statistics: Thirteen million people are now infected with the AIDS virus globally; one million had become infected within the previous six months.|1~ "Averting one infection does not mean just averting the impact of one case," Merson emphasized. "It means breaking the chain of transmission to prevent not one but perhaps hundreds or thousands of cases." Merson said that developing countries are increasingly bearing the burden of the HIV pandemic. He predicted that in this decade AIDS will break out of the inner cities to become more prevalent in suburban and rural "Main Street USA."

* Occupational exposure. The Centers for Disease Control (CDC) has found that the largest number of documented occupational HIV infections is shared equally by laboratorians and nurses. Carol A. Ciesielski, M.D., a medical epidemiologist with the Surveillance Branch of the AIDS program at the CDC, announced that as of June 30, 31 health care workers had contracted HIV from an occupational exposure: 12 nurses, 12 laboratorians (all but one from clinical labs), four physicians, one respiratory technician, one nurse's aide, and one employee from the housekeeping and maintenance department.|2~ The risk of contracting the virus from a single injury from a needlestick contaminated with the virus remains 0.3%.

A national surveillance study conducted by the CDC revealed that all 11 infected clinical laboratorians had documented occupational seroconversions. This means that 1) they had no known risk factors; 2) they were involved in a documented percutaneous (needlestick) or mucocutaneous (splash of blood in the face) exposure at work; 3) the source individual tested positive for HIV; 4) the laboratorians' baseline specimens were negative for HIV antibody; and 5) they became infected with HIV (seroconverted) within 12 months after exposure.

During an interview with MLO, Russ Metler, R.N., M.S.P.H., a nurse epidemiologist with the CDC, explained that 9 of the 11 incidents were percutaneous injuries.|3~ One episode occurred from a broken vial, one from grabbing a slipping needle, two from inadequate needle disposal, two from recapping a needle, and three from unexpected movement from a patient or equipment. Half of the needlestick injuries happened using standard vacuum tube blood collection devices and one quarter using winged-steel needles. More than half (58%) of the infections occurred during phlebotomy.

Of these nine workers, one experienced a mucocutaneous exposure as well, as did the remaining two laboratorians. Their exposures occurred while they were working with an apheresis machine or using blood collection tubes. Metler emphasized the importance of wearing face protection in the laboratory.

Among the most stirring findings to be announced at the conference was the documented seroconversion by a health care worker more than six months after infection. The United States Public Health Service (USPHS) may be forced to rethink its follow-up testing recommendations, which now specify that a baseline specimen be taken, followed by testing at 6 weeks, 12 weeks, and 6 months. Asked to comment on the need to extend final testing, David Bell, M.D., chief of the HIV Infections Branch of the Hospital Infection Program at the CDC, told MLO that these recommendations are merely guidelines indicating minimum action to be taken after an occupational exposure.

* Phlebotomy. In the summer of 1990, before OSHA's bloodborne pathogens standard was finalized, the CDC and the National Institutes for Occupational Safety and Health (NIOSH) conducted a joint study of 2,463 phlebotomy procedures performed at three hospitals.|4~ At hospital A, employees were required to wear gloves during phlebotomy; gloves were therefore used 99% of the time. At hospitals B and C, which had no such requirements, gloves were worn less than 20% of the time.

Further investigation showed that phlebotomists at hospital A followed CDC needle disposal guidelines 99% of the time; at hospital B, 40% of the time; and at hospital C, a frightening 1% of the time. Needlestick injuries ranged from one needlestick per phlebotomist every 34 months to one every 73 months. This study indicates the need to standardize CDC's recommended universal precautions, largely accomplished by OSHA's standard.

* Classifying exposures. Determining whether an HIV-infected person acquired the virus in the workplace can be difficult, CDC representatives explained. For instance, a laboratorian who has several sex partners and reports a needlestick is more likely to have contracted the AIDS virus from his or her sex practices than in the lab. Still, the CDC presented 65 additional cases that are believed to represent occupational exposures. Either these cases lacked the initial baseline specimens that officially document a seroconversion or source specimens could not be obtained for testing.

The CDC announced that health care workers represent 4.8% of adult AIDS cases whose occupations are known. As of the end of June, the organization knew of 8,467 health care workers with HIV or AIDS. Of these, 83% had other identifiable risks unrelated to their jobs.

* Controversial drug. While the CDC does not officially recommend zidovudine (azidothymidine, or AZT) for occupational exposures, the agency sits on the fence by not not recommending it. Nevertheless, AZT treatment is becoming generally accepted for HIV exposure.

To find out how many facilities use AZT after an occupational exposure, NIOSH surveyed all 160 hospitals affiliated with the American Medical Association (AMA) Graduate Medical Education Program that offer accreditation in infectious diseases, along with 100 randomly chosen U.S. hospitals and 161 acute-care hospitals in Minnesota.|5~ Altogether, 76% of the program hospitals, 25% of the random U.S. hospitals, and 18% of the Minnesota hospitals make this regimen available. Facilities whose staff were epidemiologically more likely to encounter HIV were more apt to offer AZT.

Rita Fahrner, R.N., M.S., clinical director of the Occupational Disease Program at San Francisco General Hospital and a leader in post-exposure counseling and follow-up for health care workers, is a member of an SFGH team that pioneered the use of AZT for post-exposure chemoprophylaxis.|6~ The team studied 108 health care workers from 19 U.S. hospitals who began AZT treatment after a potential exposure. Eighty-three percent began taking the drug within three hours and 95%, including the first group, within 12 hours. Almost one-third stopped treatment when the source patient was shown to be HIV-negative. Approximately 4 in 10 workers who completed the treatment showed no subjective symptoms. Those showing symptoms such as fatigue, headaches, insomnia, and nausea (about one in five) received lower doses. All abnormal hematology parameters returned to normal 12 weeks after cessation of treatment. The team concluded that prompt provision of AZT to exposed health care workers is safe and feasible.

Fahrner estimates that as many as 80% of major U.S. health care facilities make some form of chemoprophylaxis available to workers. New data support earlier use of AZT for those exposed to HIV. Still, it is not clear if prophylactic AZT can actually prevent HIV infection from a needlestick. Treatment is no longer limited to AZT, according to Keith Henry, M.D., director of HIV/AIDS Programs at the St. Paul-Ramsey Medical Center in St. Paul, Minn. Nucleoside analogs similar to AZT--ddI and ddC--will be used to prolong life as well, he said. Henry told MLO that he is "increasingly nervous about whether AZT is the best thing" to use and expressed concern about reports suggesting that the AIDS virus could become resistant to the drug. He warned that "the waters ahead" were "still very murky."

* Biosafety. Over the last few years, biosafety equipment and products have undergone a dramatic transformation to reduce the likelihood of HIV transmission. Much clinical laboratory equipment is largely automated and requires minimal manipulation during preventive maintenance and cleaning protocols, thereby reducing the risk of exposure incidents. A representative from a manufacturer of laboratory instrumentation predicted at the conference that tests currently classified under CLIA '88 as highly complex will soon become available as moderately complex through newer single-step devices that utilize state-of-the-art electronics and computerization to reduce error.

Some participants at the conference expressed reservations about the "black box" trend in lab testing. Renowned microbiologist William J. Hausler Jr., Ph.D., director of Iowa Hygienic Laboratories, University of Iowa, Iowa City, cautioned that despite the urgent need for equipment that reduces biohazards, such technology may begin to raise a generation of laboratory incompetents who are unable to alter a procedure or troubleshoot a system.

Conference attendees agreed that the push for biosafety in the workplace is putting increased financial pressures on employers, particularly in this era of extreme cost containment and significantly reduced reimbursement rates. According to Dr. Bell of the CDC, about half of all needlestick injuries could be prevented by using needles with safer designs. Such products are currently available but far more expensive than traditional needles. Bell predicted that the personnel shortage and the pressures of potential litigation will soon force employers to capitulate.

Scott Campbell, R.N., M.S.P.H., administrative director of HIV/AIDS Programs at the St. Paul--Ramsey Medical Center, told MLO that he envisions "anti-needlestick devices as the wave of the future." He noted that safer procedures and devices are already being implemented in some facilities. For instance, surgeons can now use special thimbles to reduce the chance of needlesticks from solid-bore suture needles.

A manufacturer of laboratory gloves introduced a new technology at the conference by which latex products are impregnated with a viricidal agent. Hopeful that this invention will provide extra protection against HIV, the company plans to manufacture a new condom that employs the same methodology.

The quality of gloves has improved tremendously in the last few years. Denise Korniewicz, D.N.Sc., R.N., associate dean for academic affairs at Georgetown University, Washington, D.C., and still considered the "glove guru," explained to MLO that considerable variation remains among brands.|7~ In a study of glove defects during nonsurgical procedures, such as phlebotomy, in hospital emergency departments, she uncovered glove failure rates ranging from 9% to 22%, depending on the brand used. As a result, Korniewicz continues to recommend that health care workers "double glove in high-risk procedures."

In a similar study, Karen Hansen, M.D., clinical instructor for the department of emergency medicine at the Johns Hopkins Hospital, Baltimore, found a significant loss of glove integrity during commonly performed emergency department procedures.|8~ After observing over 300 such procedures, she determined that gloves can leak even without visible holes. The glove failure rate was 7.7%; 4.3% failed during phlebotomy. She also found that loss of glove integrity is associated with how long they are worn, which suggests that gloves should be changed frequently, before holes become visible.

* Losing employment. Many conference attendees expressed their growing concern about where health care professionals should look for employment after testing positive for HIV. While this issue has had little impact on clinical laboratorians, it has become all too familiar to physicians and dentists. Employers are increasingly asking HIV-positive professionals, including surgeons, who might put their patients at risk to step down from their positions on a voluntary basis.

Benjamin Schatz, J.D., executive director of the Medical Expertise Retention Program, San Francisco, told conference delegates that many such individuals suddenly face a sharp drop in income coupled with enormous professional debt. They are confronted with loss of confidentiality and professional status as well as a lowered self-image. Schatz urged professional organizations to advocate the creation of programs to absorb displaced health care employees and suggested that the clinical laboratory might be one such harbor.

* Old enemy, new concern. An alarming surge of infectious tuberculosis has been noted, particularly in the U.S. Unlike HIV, multi--drug-resistant tuberculosis (MDR-TB) is highly contagious and "poses a significant risk to health care workers," said Michael Mullen, M.D., acting chief of infectious diseases, Cabrini Medical Center, New York City.|9~ Mullen urged strict isolation for HIV-positive patients with fever and respiratory symptoms that suggest TB. "Isolation must continue until there is a clear response to treatment, and follow-up monitoring of respiratory isolates must be done," he said, adding that "extreme caution must be practiced when patients are on treatments such as aerosolized pentamidine."

Dr. Mullen reported a jump of MDR-TB nationwide from 8 of 132 TB cases between 1982 and 1987 to 24 of 74 cases from December 1990 through May 1991. Nosocomial spread was indicated in that 14 of 15 isolates were genetically identical.

Margaret Fischl, M.D., professor of medicine at the University of Miami School of Medicine, also reported a rising incidence of the disease at the hospital associated with her facility.|10~ Fischl concluded that "we were dealing with nosocomial transmission of MDR-TB, probably in crowded waiting rooms of our outpatient clinic."

* Constant vigilance. Clinical laboratorians will remain on the front lines in HIV disease for the rest of this century. While the risk of contracting the virus in the laboratory remains small, it is significant enough to warrant our constant vigilance over biosafety in the workplace.

As leaders in the profession, we must join forces to fight the discrimination and hysteria about AIDS that misinformation occasionally inspires among the public. Our response to the epidemic must be firmly grounded in science--not silence. Our response must be framed as well in sensitivity and compassion.

References

All references below represent presentations at the VIII International Conference on AIDS, Amsterdam, The Netherlands, July 19-24, 1992.

1. Merson MH. Opening address. July 19.

2. Ciesielski CA, Metler R, Hammett T, et al. National surveillance for occupationally acquired HIV infections in the United States. PoC 4143. July 20.

3. Metler R, Ciesielski C, Ward J, Marcus R. HIV seroconversion in clinical laboratory workers following occupational exposure, United States. PoC 4147. July 20.

4. McCabe K, Henry K, Campbell S, et al. Differences in universal precautions policies and practices among phlebotomists at three Minnesota teaching hospitals. PoC 4146. July 20.

5. Campbell S, Henry K. Zidovudine (AZT) use after HIV exposure: A survey of U.S. hospitals. PoC 4142. July 20.

6. Fahrner R, Beekman SE, Kozial DE, et al. Safety of zidovudine (ZDV) as post-exposure chemoprophylaxis to healthcare workers (HCW) after occupational exposures to HIV. PoC 4132. July 22.

7. Korniewicz D, Hansen K, Kelen G, Larson E. A comparative analysis of glove use in the emergency department. PoC 4820. July 22.

8. Hansen K, Korniewicz D, Larson E, et al. Loss of glove integrity during common ED procedures. PoC 4547. July 22.

9. Mullen M, Soumakis S, Lessnau K, et al. Multi-drug resistant tuberculosis (MDR-TB) in patients infected with HIV. TuB 0535. July 21.

10. Fischl M, Uttamchandani R, Daikos R, et al. Outbreak of multiple resistant tuberculosis (MDR-TB) among patients with HIV infection. TuB 0534. July 21.

Dr. Brown, a member of MLO's Editorial Advisory Board, is director of microbiology and of health and environmental affairs at Roche Biomedical Laboratories, Raritan, N.J.
COPYRIGHT 1992 Nelson Publishing
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Author:Brown, James W.
Publication:Medical Laboratory Observer
Date:Oct 1, 1992
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