Kent A. Sepkowitz, MD
http://www.annals.org/cgi/content/full/125/11/917
1 December 1996 | Volume 125 Issue 11 | Pages 917-928
Background: Health care workers are at occupational risk for a vast
array of infections that cause substantial illness and occasional
deaths. Despite this, few studies have examined the incidence,
prevalence, or exposure-associated rates of infection or have considered
infection-specific interventions recommended to maintain worker safety.
Objective: To characterize the type and frequency of infections, the
recommended interventions, and the costs of protecting health care
workers. Part II of this two-part review focuses on infections caused by
bloodborne organisms, organisms spread through the oral-fecal route, and
organisms spread through direct contact. It also reviews established
interventions for controlling transmission.
Data Sources: A MEDLINE search and examination of infectious disease
and infection control journals.
Data Selection: All English-language articles and meeting abstracts
published from January 1983 to February 1996 related to occupationally
acquired infections among health care workers were reviewed. Outbreak-
and non-outbreak-associated incidence and prevalence rates were derived,
as were costs to prevent, control, and treat infections in health care
workers.
Data Synthesis: Occupational transmission to health care workers was
identified for numerous diseases, including infections caused by
bloodborne organisms (human immunodeficiency virus, hepatitis B virus,
hepatitis C virus, Ebola virus), organisms spread through the oral-fecal
route (salmonella, hepatitis A virus), and organisms spread through
direct contact (herpes simplex virus, Sarcoptes scabiei). Most
outbreak-associated attack rates range from 15% to 40%. Occupational
transmission is usually associated with violation of one or more of
three basic principles of infection control: handwashing, vaccination of
health care workers, and prompt placement of infectious patients into
appropriate isolation.
Conclusions: The risk for occupationally acquired infections is an
unavoidable part of daily patient care. Occupationally acquired
infections cause substantial illness and occasional deaths among health
care workers. Further studies are needed to enhance compliance with
established infection control approaches. As health care is being
reformed, the risk for and costs of occupationally acquired infection
must be considered.
More than 10 years have elapsed since the last major consideration of
occupationally acquired infections in health care workers [1, 2]. Since
then, much has changed—new infections have been identified, diagnostic
tests for previously recognized diseases have been improved, the use of
molecular epidemiologic techniques in outbreak investigations has
increasingly become routine, and outpatient and home care have become
more common.
The topic of occupationally acquired airborne infections in health
care workers was addressed in part I of this two-part review [3].
Infections such as occupationally acquired tuberculosis, varicella-zoster,
measles, and respiratory syncytial virus infections were considered, as
were ethical and historical concerns. Part II of this review discusses
infections caused by bloodborne organisms (such as human
immunodeficiency virus [HIV], hepatitis B virus [HBV], hepatitis C virus
[HCV], cytomegalovirus [CMV], and Ebola virus), organisms spread through
the oral-fecal route (such as salmonella and hepatitis A virus [HAV]),
and organisms spread through direct contact (such as herpes simplex
virus and Sarcoptes scabiei). It then summarizes known interventions,
including handwashing, vaccination, and prompt placement of potentially
infectious patients into appropriate isolation. The risks to health care
workers inherent in health care delivery should be considered by
planners of health care for the next century.
Bloodborne Transmission
Bloodborne transmission Table 1 has received increased attention with
the advent of the acquired immunodeficiency syndrome epidemic and, more
recently, the outbreak of Ebola virus infection. Although many
nonmedical occupational groups are at risk for diseases caused by
organisms transmitted through the airborne or oral-fecal route, health
care workers are one of the few groups at risk for the transmission of
bloodborne pathogens. In addition to blood-to-blood transmission, some
of these pathogens may be transmitted in saliva, as occurs with CMV and
B virus infection.
Table 1. Occupationally Acquired Infections Resulting from Bloodborne
Transmission*
| Table 1. Occupationally Acquired
Infections Resulting from Bloodborne Transmission*
|
HIV Infection
The occupational risk for transmission of HIV has been the subject of
numerous thorough reviews [9, 34-40] and is not considered in detail
here. The rate of seroconversion after exposure ranges from 0.1% to 0.4%
[4, 5, 35]. In general, a large inoculum—including that from a source
case with more advanced disease, a stick with a large-bore
blood-containing needle, or a more severe injury—is associated with a
higher rate of transmission [41].
Occupational transmission has been confirmed in 49 health care
workers and may have occurred in 102 others [6] (Table 2). Percutaneous
exposure alone was the source of transmission for most confirmed cases
of infection (42 persons). The optimal management of health care workers
after exposure remains unknown. A recent retrospective, case–control
study examined risks associated with transmission in 31 case-patients
and 679 controls [41]. In this analysis, the use of zidovudine was
associated with a 79% risk reduction, although zidovudine failure has
occurred [42]. Provisional Public Health Service recommendations include
three antiretroviral drugs (zidovudine, lamivudine, and indinavir) for
high-risk exposures [7, 43].
Table 2. Health Care Workers with Documented and Possible Cases of
Occupationally Acquired HIV Infection in the United States, through
1995*
| Table 2. Health Care Workers with
Documented and Possible Cases of Occupationally Acquired HIV
Infection in the United States, through 1995*
|
Hepatitis B
Hepatitis B virus was one of the first bloodborne pathogens to be
recognized as an occupational risk among health care workers [44-46]. An
early review [46] found a preponderance of cases of hepatitis B among
pathologists, laboratory workers, and blood bank workers, alerting
investigators to the risks of exposure to blood. Subsequent studies
confirmed these early observations [47-63]. In general, the
seroprevalence of HBV in health care workers is twofold to fourfold
higher than that of blood donor controls [47, 61]; the highest rates are
seen among dentists [8, 47]; physicians [8, 47, 61, 63]; laboratory
workers [8, 47, 63, 64]; dialysis workers [63]; cleaning service
employees [51, 62]; and nurses [8], including emergency department
nurses [56]. Widespread transmission may occur from a single surgical
procedure [65]. Many infections in health care workers are asymptomatic
[48].
In prevaccine surveys, the annual incidence of hepatitis B was 5 to
10 times higher among physicians and dentists than among blood donors
and more than 10 times higher among surgeons, dialysis workers, persons
caring for the mentally handicapped, and laboratory workers exposed to
blood [47, 61, 66].
The risk for transmission from a single needlestick varies according
to E antigen status: 1% to 6% for E antigen-negative blood compared with
22% to 40% with E antigen-positive blood [8-10, 67]. However,
transmission of E antigen-negative blood has caused fulminant hepatitis
requiring liver transplantation [68]. Hepatitis delta virus has been
transmitted to a surgeon [69]. The quality-adjusted loss in life
expectancy is similar for persons who receive needlesticks involving a
source patient who has HBV infection and for persons who receive
needlesticks involving a source patient with HIV infection [70, 71]. Not
all cases of HBV transmission are explained by needlesticks, suggesting
that other modes of spread may be possible [8, 9, 72].
Infection control interventions, such as the segregation of dialysis
recipients according to surface antigen status [73, 74] and vaccination
[74, 75], have effectively reduced occupational acquisition of HBV.
However, the Centers for Disease Control and Prevention (CDC) calculate
that 6500 to 9000 new HBV infections occurred among health care workers
in 1990 [8]. Given the natural history of HBV infection, 300 to 950 of
these health care workers (5% to 10%) will eventually develop chronic
HBV infection that will lead to death from cirrhosis in 100 to 150
persons and to fatal hepatocellular carcinoma in 25 to 40 persons [8].
Despite this, HBV vaccination of health care workers remains incomplete.
In one study, 23% of health care workers were unvaccinated [52], a rate
similar to that of anesthesiologists in the United Kingdom [76]. A
three-vaccine series is 88% effective [77, 78]; decreased response is
seen among recipients who are older, who smoke, or who are obese [77,
78].
Hepatitis C
The 1990 introduction of a test for HCV infection has dramatically
improved our understanding of disease epidemiology. Because HBV and HCV
have similar modes of transmission, it was assumed that groups of health
care workers at increased risk for hepatitis B also would be at risk for
hepatitis C [19, 52, 60]. This, however, has not proven to be true for
many groups, including dialysis workers [79-82], laboratory workers
[83], persons who work with the mentally impaired [84], and surgical
staff [83]. Indeed, although "occupational exposure" accounts for about
2% of all cases of hepatitis C [19], the seroprevalence of HCV among
health care workers is roughly similar to that of the general population
(about 1%) [83, 85-89]. Dentists do have increased risk [16, 17]: In one
serosurvey [16], significantly more dentists (1.7%) than blood donors
(0.13%) were seropositive for HCV; the highest rate of seroprevalence
was seen among oral surgeons (9%).
Seroconversion occurs in 1.2% to 10% of nonimmune health care workers
who receive needlesticks from a source patient with hepatitis C [11-15].
Variation among control populations [90-92], variation in employee
populations [18, 93, 94], and variation in the sensitivity of tests for
HCV [19] have contributed to the lack of consensus about risk [14, 18,
94]. Optimal management of a needlestick is unknown, but the
administration of immune globulin is not recommended [18, 40].
Cytomegalovirus Infection
The prevalence of CMV infection in the United States varies according
to geography, patient age, and group studied and ranges from 40% to 95%.
The annual community incidence among adults is about 2% [21].
Transmission of CMV may occur through sexual contact or through contact
with infectious blood. Respiratory secretions, saliva, and urine may
also transmit CMV, as shown by increased rates of CMV infection among
day care workers (8% to 10% per year) [95, 96]. Early incidence [97-99]
and prevalence studies [100], as well as meta-analyses [101, 102] and
reviews [103, 104], suggested that pediatric health care workers had
elevated risk, similar to that of day care workers. Subsequent reports
[20, 21, 35, 105, 106], however, have not shown this risk, perhaps
because many recent studies were done in the era of universal
precautions. Similarly, no increase in CMV infection among dialysis
workers [107] or renal transplantation workers [108] has been found.
Studies using molecular epidemiologic techniques have also shown that
health care workers are at low risk for occupational transmission of CMV
[109, 110]. No transmission was documented among 188 health care workers
at a pediatric chronic care or neonatal unit in which many of the
patients were heavy CMV shedders [110]. Molecular analysis of CMV
recovered from one of two nurses who seroconverted showed discordance
with CMV taken from a known occupational contact and concordance with
CMV from a family member with new disease.
Ebola Virus Infection and Other Viral Hemorrhagic Fevers
The recent outbreak of Ebola virus infection in Zaire involved 296
cases and was associated with a 79% mortality rate [22-24]. At least 90
persons (32%) were health care workers [24, 25], a fact that led the CDC
to issue recommendations for the management of persons with suspected
viral hemorrhagic fevers [26]. Among the recommended practices were use
of universal precautions, use of strict barrier protection, restriction
of workers and visitors, and use of negative-pressure ventilation in the
presence of respiratory symptoms.
In a 1979 outbreak of Ebola virus infection in Sudan, persons who
provided nursing care were five times more likely to develop disease
than were those who provided no care [111]. In all, 34 cases of
infection occurred and 22 persons died. Similar outbreaks involving
health care workers have been reported with Crimean hemorrhagic
fever-Congo virus infection in Pakistan, where 10 of 17 exposed workers
developed disease and 2 died [112]; Lassa fever virus infection on an
obstetrics ward, where 7 of 26 exposed workers developed disease and at
least 1 died [113]; and Marburg virus infection [114, 115]. Ribavirin
was effective as therapy for 3 health care workers with Crimean
hemorrhagic fever-Congo virus [116].
B Virus Infection
Fatal, occupationally acquired infection with B virus (Herpesvirus
simiae) was described in 1932, when a physician died of
encephalomyelitis 3 days after being bitten by a clinically well rhesus
monkey [117, 118]. Since that time, more than 24 infections with B virus
have occurred in humans, and 18 persons have died [119]. The peak
incidence of B virus infection occurred in 1957-1958, in conjunction
with the production and testing of poliomyelitis vaccines [119]. In the
1980s, a cluster of four cases (two of which were fatal) occurred in a
research facility in Pensacola, Florida [27], leading to the development
of new recommendations for monkey handlers [28]. Treatment with
acyclovir may be effective [27, 29], but the optimal duration of therapy
is unknown and may extend years.
Other Infections
Creutzfeldt-Jakob disease is a uniformly fatal neurodegenerative
disorder that has been the subject of extensive epidemiologic
investigation [31, 32]. Health care workers are not considered to be a
group at risk [31], but cases have been reported in two neurosurgeons
[31, 32], two histopathology technicians [120, 121], and one pathologist
[122]. In none of these cases could a specific incident that may have
led to transmission be recalled. Recent recommendations stress
sterilization of equipment to minimize the risk [30].
Outbreaks of Epstein-Barr virus infection have seldom been reported.
Transmission of Epstein-Barr virus to 9 of 29 medical staff (31%) in an
obstetrics and gynecology clinic was never explained [123].
Investigators at a hospital that treated hundreds of cases of
nasopharyngeal carcinoma suggested that nosocomial spread was a major
source of Epstein-Barr virus infection among health care workers at
their institution [124]. Occupationally acquired cases of syphilis
[125], malaria [126], and yellow fever [127] have been reported.
Oral-Fecal Transmission
Enteric pathogens spread in various ways, including through the
ingestion of contaminated food; through direct person-to-person contact;
and through contact with infectious waste, usually feces (Table 3).
Insufficient handwashing by health care workers probably contributes
more to the transmission of these pathogens than to the transmission of
bloodborne or airborne pathogens.
Table 3. Occupationally Acquired Infections Resulting from Oral-Fecal
Transmission*
Salmonellosis
The number of cases of salmonellosis has increased steadily since the
1950s, and food-related outbreaks continue to occur. The effect of
contaminated food was vividly shown by a recent outbreak that was traced
to ice cream and that caused more than 200 000 cases of salmonellosis
across 41 states [153]. In general, institutional disease accounts for
10% to 30% of all cases [138, 154, 155]. Hospitals, nursing homes,
psychiatric facilities, pediatric wards, and nurseries are common sites
[138, 154-157].
Massive contamination of mashed potatoes was responsible for a large
outbreak at a hospital in Jordan [128], where 183 of 619 persons (19.6%)
(including 150 hospital employees) developed disease. Investigation
showed that 11 of 61 kitchen workers (18%) were infected with
salmonella; all had been negative on cultures taken 3 months earlier,
suggesting that routine surveillance cultures may not be useful.
Person-to-person transmission of salmonella occurred in a hospital in
Maine [158], where several workers who drank tainted eggnog developed
salmonellosis. As the outbreak progressed, at least eight additional
workers who had not drunk eggnog also developed disease.
Person-to-person spread has been suggested by other studies [159, 160],
including the report of an outbreak that involved fasting patients who
had recently had gastrectomy and infants who were not receiving hospital
food. In a nursing home in Tennessee, 8 of 160 employees (5%) developed
salmonellosis; the highest attack rate was seen in laundry workers
[129]. Several laundry workers had no direct contact with infected
patients, suggesting that transmission occurred through contaminated
linen.
Interrupting an identified outbreak may be difficult. In Cincinnati,
Ohio, 24 of 52 kitchen workers were found to have Salmonella drypool,
which accounted for at least 11 cases of salmonellosis among staff who
ate food that had been prepared at the hospital [161]. The epidemic was
stopped only after 50 of 52 kitchen workers were treated with
trimethoprim-sulfamethoxazole. Because 32% of treated employees
developed reactions to drug treatment, this approach may not be
advisable for routine outbreaks. In one study [162], the cost of
identifying and treating one salmonella-infected health care worker,
including cultures, antibiotic therapy, and lost work time, was $3500.
Hepatitis A
The number of cases of hepatitis A gradually increased in the United
States in the 1980s; incidence peaked in 1989 [163]. Common risk factors
for the acquisition of HAV include contact with an infected person
(26%), employment in or attendance at a day care center (14%), and use
of injection drugs (11%) [163]. The overall prevalence rate of HAV
infection in the United States is about 38%, similar to rates described
in health care workers (35% to 54%) [164-166]. In one report [165], the
rates of antibodies to HAV were significantly higher in nurses older
than 30 years of age than in office workers; in another study, charwomen
had the highest rate [166].
Many outbreaks have been reported in pediatric or neonatal intensive
care units [130, 133-136] and orphanages [167]. A neonate who acquired
HAV through a transfusion spread the organism to 10 of 61 susceptible
nurses (16%) [136]. An infected child who had an immune defect that
resulted in an inability to seroconvert to HAV remained undiagnosed for
a protracted period, leading to transmission of HAV to 15 of 102 staff
[131]. Adults with diarrhea have also transmitted the virus to health
care workers [168, 169].
An outbreak of HAV infection in a burn unit occurred despite the use
of appropriate infection control measures, and HAV was spread to 11 of
59 susceptible nurses (18.6%) [132]. Eating on the hospital ward was the
most important risk factor for infection. Other nosocomial outbreaks
have resulted from the consumption of contaminated food, including
orange juice [170] and sandwiches [171]. One outbreak resulted in 66
cases of clinical or subclinical disease [171].
The intramuscular administration of immune globulin to persons who
have contact with HAV-infected patients has been used effectively for
many years to prevent secondary cases. Defining which, if any, health
care workers should routinely be vaccinated for HAV is currently being
discussed [137, 172].
Shigellosis
Given the small inoculum size required for transmission of shigella
[173], the reason for the relative infrequency of nosocomial shigella
infection has been the subject of speculation but remains obscure [138].
Outbreaks in day care centers have been reported [153, 174]. At a
teaching hospital in Kenya [175], salmonella accounted for 10% and
shigella accounted for 2.5% of 360 cases of nosocomial diarrhea. In
another report [139], 3 of 32 workers in a newborn nursery developed
shigellosis. All were chronic nail-biters. The cost of controlling the
outbreak was $5000.
Cryptosporidiosis
Cryptosporidia have been spread to a medical intern and possibly
other staff [176], a nurse [177], and a laboratory researcher [178].
Proper infection control techniques failed to control an outbreak in
Wales, where 5 of 16 nurses developed disease [140]. This outbreak was
perpetuated by severe environmental contamination; replacement of sinks
and hand basin taps with leg-operated machinery proved to be an
effective intervention. Veterinarians and animal handlers also have an
increased risk for cryptosporidiosis. In one outbreak [141],
cryptosporidiosis developed in 10 of 20 veterinary students who worked
with calves that had died of the disease. This outbreak was similar to
another calf-related outbreak, in which 12 of 18 animal handlers became
infected [142].
Helicobacter pylori Infection
Several recent reports have examined the seroprevalence of antibodies
to Helicobacter pylori among health care workers [143-147]. One found
that seroprevalence was higher among endoscopists (69%) than among
internists (40%) [145]. Two other studies [143, 147] found that about
52% of endoscopists and only about 14% to 21% of blood donors were
seropositive for H. pylori [143, 147]. Dentists have no increased
seroprevalence despite contact with saliva [144]. These findings suggest
that contact with contaminated equipment, rather than routine patient
care or contact with saliva [144], is an important mode of transmission.
Other Infections
Clostridium difficile has emerged as an important cause of
hospital-acquired diarrhea and has been cultured from the hands of 14%
to 59% of asymptomatic health care workers during outbreaks [179, 180].
However, controversy exists about the potential role of C. difficile as
an occupationally acquired organism [181-183]. Possible nosocomial
transmission of fatal C. difficile infection to an otherwise healthy
worker has recently been reported [184]. Several nursing home outbreaks
of infection with the Norwalk virus (a small, round-structure virus)
have resulted in rates of transmission to staff that range from 30% to
50% [148-152]. In one outbreak, "care attendants" had an incidence rate
of 92% [149]. In an outbreak of Escherichia coli O157: H7-associated
hemorrhagic colitis in a nursing home [185], 18 of 137 staff members
(13%) developed symptoms; 5 of the 18 had bloody diarrhea. No health
care worker developed the hemolytic-uremic syndrome. Cholera has spread
to staff [186], but studies done before vaccination found no risk to
personnel on a polio ward [187].
Eating hospital food and drinking hospital beverages expose health
care workers to the same risks faced by patients and visitors, as shown
by hospital food-related outbreaks of salmonellosis [128, 158, 161],
hepatitis A [170, 171], yersiniosis [188], campylobacteriosis [189],
cyclospora infection [190], and typhoid fever [191].
Direct Contact
Infection may spread to health care workers as a result of direct
contact. Outbreaks of scabies, particularly among nurses and laundry
workers, have been reported from several hospitals [192-195]. In one
hospital [193], almost 300 health care workers were affected, including
45 of 200 laundry workers (22.5%), 126 of 1448 nurses (8.7%), and 32 of
87 health care workers (36.8%) who had direct contact with patients. The
outbreak cost about $50 000 for days of work missed and for treatment.
In another outbreak [194], secondary spread to the spouses of health
care workers was seen. A large, sustained outbreak at an extended-care
facility [195] resulted in the infection of 26% of the staff, including
half of all nurses.
Cutaneous herpes (herpetic whitlow) is an occupational hazard for
dentists; anesthesiologists; dialysis technicians; physiotherapists;
physicians; and nurses [196, 197], particularly nurses in intensive care
units [196, 198, 199]. That dermatologists face risk associated with
laser treatment of warts with lasers has been suggested [200, 201],
including a recent study [202] in which molecular epidemiologic
techniques were used. Tinea corporis may spread to staff [203, 204],
further thwarting control efforts.
Specific Groups of Health Care Workers at Risk
Laboratory personnel, veterinarians and animal handlers,
pathologists, surgeons, dentists, anesthesiologists, and laundry workers
are at risk for an array of specific infections (Table 4). In addition,
the concerns of pregnant health care workers are considerable and unique
because certain otherwise mild infections may affect fetal development.
Table 4. Occupationally Acquired Infections Encountered in Specific
Groups of Health Care Workers*
Laboratory-acquired infections have been extensively studied
[205-207]. Collins [205] identified 2168 infections and 48 deaths from
diseases ranging from brucellosis and Q fever (the most common) to
rabies and the plague. The potential danger of working in laboratories
is dramatically illustrated by the fate of Ricketts (for whom Rickettsia
was named), who died of laboratory-acquired rickettsiosis [205].
Neisseria meningitidis has fatally infected laboratory workers [208].
Although many clinical health care workers receive prophylaxis after
exposure to N. meningitidis, studies have not documented the spread of
this organism to health care workers in the clinical setting [209].
Interventions
Despite the seemingly limitless number of infections that health care
workers can acquire on the job, the interventions to prevent
transmission are simple, well known, and effective. Compliance with
three practices—handwashing, vaccination, and appropriate isolation of
infected patients—can control transmission dramatically and
cost-effectively.
Handwashing
Handwashing is the oldest, simplest, and cheapest way to control the
nosocomial spread of infectious organisms. In the 1840s, Semmelweis
introduced the practice of "hygienic hand disinfection" on obstetric
wards in Vienna, decreasing the maternal mortality rate from 13.7% to
1.3% [241-243]. Since that time, handwashing has become routine for all
persons doing any surgical procedures; however, workers involved in
medical care have notoriously low rates of handwashing—usually less than
50% [244-248].
Numerous studies have examined the specific aspects of handwashing,
including type of soap [249, 250], type of sink [251], drying method
[252], and method of scrubbing [243, 253-255]. One study showed that
chlorhexidine was both significantly more effective and more often used
than alcohol and soap [249]. Additional strategies to improve compliance
[244, 247, 251] are necessary because compliance, not brand of soap or
type of sink, remains the major obstacle to preventing transmission. In
addition to preventing patient-to-patient spread, handwashing may
prevent the acquisition by health care workers of such infections as
those caused by rhinovirus, respiratory syncytial virus, HAV,
adenovirus, and salmonella. Emphasis of this might promote compliance
and lead to an overall reduction of transmission.
Vaccination
Recommendations about vaccines are updated frequently [256], but
vaccination of health care workers remains incomplete [257-259]. Indeed,
compliance with HBV vaccination remains appalling: In a recent survey in
an inner-city hospital, 23% of workers were unvaccinated [52]. Health
care workers are often the source of outbreaks of measles and rubella
[257] and, less commonly, HBV infection [260], further emphasizing the
need for improved compliance with vaccination. A demonstration of
evidence of antibodies to vaccine-preventable diseases, including
measles, mumps, rubella, and hepatitis B, is required of employees at
many hospitals. The varicella-zoster virus has recently been recommended
[261], whereas the role of the HAV vaccine is being determined.
Isolation
Appropriate isolation of infected patients is another time-honored
practice [262]. It is the most complicated and potentially expensive of
the three standard interventions. Difficulties arise when trying to
balance the need to protect health care workers against the realities of
cost, as shown by the recent debate surrounding tuberculosis control
[263]. A common sense approach may find an acceptable middle ground
[264, 265]. In general, universal precautions for infections with
bloodborne organisms, respiratory and droplet isolation precautions for
infections with airborne organisms, and contact isolation precautions
(or enteric precautions) for infections caused by organisms spread by
the oral-fecal route are effective and widely used [33]. Updated
guidelines for isolation precautions have recently been published [33].
Conclusions
Public attention has recently focused on the risk to patients posed
by infectious health care workers. Transmission of HIV from an infected
dentist to four patients [266] stirred a national debate in the United
States about mandatory HIV testing of health care workers. Workers have
been the source of many infections other than HIV infections, including
tuberculosis [267], hepatitis B [260], measles, and rubella [257].
Little public concern or awareness, however, has been directed toward
the risk to health care workers of caring for contagious persons,
despite the continuing illness and occasional death that result from
occupationally acquired diseases.
Several recent developments have changed many aspects of occupational
risk. Old diseases that may be spread to health care workers, such as
tuberculosis and diphtheria, have reemerged, forcing the reexamination
of existing infection control policies [268]. New technology has
identified old infections, such as hepatitis C. This, in turn, has been
followed by numerous studies delineating the natural history and
transmission rates of disease, including risk to health care workers
[11-19, 79-94]. Seemingly new diseases with undefined risks, such as HIV
and Ebola virus infection, have become evident, leading to appreciation
of risks to health care workers and recommendations for worker safety
[7, 26].
Recognition and confirmation of outbreaks, as well as improved
understanding of transmission [269, 270], rely increasingly on molecular
epidemiologic techniques. These techniques have been applied to
investigations of many diseases, including CMV infection [109],
adenovirus infection [271, 272], hepatitis B [260], hepatitis C [273],
HIV infection [274], and tuberculosis [275, 276]. Molecular analysis may
identify previously undiscerned outbreaks [275] or rule out others
[276].
The recent trend toward an increase in the use of outpatient care has
also changed the risk for occupationally acquired infection, as well as
the groups of health care workers at risk [64, 277, 278]. In 1867,
Simpson expressed his hope that, given the high concentrations of sick
patients, "hospitals should not become pesthouses, and do more harm than
good" [279]. Since that time, the risk posed to patients and staff by
nosocomial infection has been repeatedly shown. In this regard, the
result of shorter hospitalizations may well be salutary, although the
risk for undetected infection may increase as patients receive more care
away from diagnostic centers.
In summary, daily patient care presents the health care worker with a
real, although small, risk for infection. Indeed, the cost to prevent,
control, and treat occupationally acquired infections is considerable,
in terms of both dollars spent and lives affected. This does not imply
that working with contagious persons is a heroic endeavor. Rather,
incurring the risk for occupationally acquired infection is necessary
for daily health care delivery. Indeed, the willingness of health care
workers to accept this risk is, in many ways, as important to health
care as their professional skills. This should be considered in the
coming years as health care delivery in the United States continues to
be reformed.
Author and Article Information
From Memorial Sloan-Kettering Cancer Center and New York
Hospital-Cornell Medical Center, New York, New York. For the current
author address, see end of text.
Acknowledgment: The author thanks Bruce Artim, JD, for research
assistance.
Requests for Reprints: Kent A. Sepkowitz, MD, Infectious Disease
Service, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box
288, New York, NY 10021.
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