Nosocomial Transmission
of Bloodborne Viruses
From Infected Health
...
by BL Johnston - 2003 -
Workers to Patients. B
Lynn Johnston, MD1 and
John M Conley, MD2 ...
www.ncbi.nlm.nih.gov Can
J Infect Dis › v.14(4);
Jul–Aug 2003
...suggesting that there are some occupations that carry
a higher risk than
others. In two studies
in the United States
(52,53) there was a
higher rate of HCV in
oral surgeons (2.0% and
9.3%) than other
dentists (0.7% and
0.97%).
ADULT INFECTIOUS DISEASE
NOTES
July/August 2003, Volume 14,
Number 4: 192
Nosocomial transmission
of bloodborne viruses from infected health care workers to patients
B Lynn Johnston MD1, John M Conly MD2
The risks to health care workers (HCWs) of
occupationally-acquired infection with hepatitis B virus (HBV),
human immunodeficiency virus (HIV) and, to a lesser extent,
hepatitis C virus (HCV) have been reasonably well quantified (1).
Evidence from the HIV and HBV experience suggests that the risk of
infection is increased where the level of viremia is high, as
manifested by high HIV viral load or the presence of hepatitis B e
antigen (HBeAg) (1). It has also been recognized that patients may
acquire one of these viruses following significant exposure to the
blood of an infected HCW (2-4). While the magnitude of this risk to
patients is considerably less than that to HCWs, the 1990 report by
the Centers for Disease Control and Prevention (CDC) that a Florida
dentist had transmitted HIV to patients in the course of dental care
triggered widespread public concern about the risk of infection from
HCWs. In 1991 CDC published recommendations for preventing HIV and
HBV transmission to patients, which included the recommendation that
HCWs who are infected with HIV or HBV (and HBeAg positive, a marker
of higher infectivity) should not perform exposure-prone procedures
unless they have sought counsel from an expert review panel (5). In
1998, Health Canada published guidelines for the management of HCWs
infected with HBV, HCV, and/or HIV (6). Both these documents
generated controversy at the time of their publication. Since that
time, however, several provincial regulatory bodies have formed
committees to advise physicians infected with these bloodborne
pathogens (BBPs) regarding their practice. This article reviews what
we know about the transmission of HBV, HCV and HIV from infected
HCWs to patients in medical and dental settings.
Hepatitis B
Several studies have examined the prevalence of HBV markers in HCWs.
A 1985 study in Italy found that prevaccination immunological
markers of current or past HBV infection were found in 23.3% of HCWs
tested, with 1.8% being HBV surface antigen positive (7). The
prevalence of serological markers for HBV in Chicago HCWs in 1983
was 15.2%, with 1% HBV surface antigen positive (8). These results
are similar to a previous study conducted between June 1977 and
October 1978 of 624 HCWs in Boston (9). A more recent prevaccination
study of HCWs in San Francisco (1984 to 1992) found that 21.7% had
markers of HBV infection (10). While it is expected that the
prevalence of HBV in HCWs will go down with community and
occupational HBV vaccination programs, in the immediate future it is
anticipated that there will continue to be chronically infected HCWs
who have come from endemic areas or previously had other
non-occupational exposures.
The first reported transmission of HBV from HCW to patient was in
1972 (11). In that study, cases of icteric hepatitis in 11 patients
were linked to a nurse with HBV, but the mode of transmission was
not determined (11). Since that time, there have been a number of
isolated transmissions and outbreaks of HBV related to patient
exposures to infected HCWs (Table 1). The methodology used in these
studies has differed considerably and many of the early studies are
flawed by several factors: the vast majority were retrospective;
case finding was confined to symptomatic patients; only a minority
of exposed patients had serological testing; and it was often
impossible to distinguish infection related to HCW exposure from
that due to other exposures. While more recent studies have been
rigorous in their follow-up of potentially exposed patients, there
still remains the difficulty of distinguishing the source of
hepatitis B infection in those who no longer have detectable viremia
for molecular typing. To date, therefore, it has not been possible
to precisely quantify the risk of transmission to patients from a
significant exposure to an infected HCW. However, it is apparent
that a number of infected HCWs have been associated with nosocomial
transmissions to patients since 1972 (2,11-34).
In an effort to develop a better understanding of the risk of
nosocomial HBV transmission, investigators in the 1970s and 1980s
did serological testing on patients cared for by HBV carrier HCWs
who had not been associated with the transmission of clinical
infection (35-37). None of these studies demonstrated transmission
of HBV from infected HCWs to patients. However, these studies had
limitations that could have affected their results. The first study
involved no surgical personnel (35). The second study had complete
serological evaluation on only 28 of 49 patients operated on by an
orthopedic resident with acute hepatitis B (36). In the third study,
of 213 patients exposed to six chronic carrier physicians (two
surgeons), it could not be determined how many were exposed to the
surgeon who was HBeAg positive (37).
Some important observations can be made by examining the studies
that have looked at transmission of HBV from infected HCWs to
patients. The limited data suggest that HBV-infected HCWs who are
not involved in invasive procedures do not transmit infection
(35,37) unless there are breaches of infection control (32). It
would appear that not all HBV- infected HCWs who perform invasive
procedures transmit infection to patients (36). However,
HBV-infected HCWs have been associated with nosocomial transmissions
(2,12-34). Physicians associated with transmissions have been at all
levels of experience including trainees, clinical assistants and
senior surgeons. Technical expertise or competence has not usually
been identified as a contributing factor in the transmissions.
In the literature on nosocomial HBV transmissions, a few specialties
appear to be over-represented, including dentistry and oral surgery,
obstetrics and gynecology, and cardiothoracic/cardiovascular
surgery. It has been suggested that these are specialties where
surgery involves one or more of the following: operating in a
confined and/or poorly visualized field, palpation of needles or
other sharp objects, or frequent exposure to sharp objects, all of
which increase the potential for the HCW’s blood to come into
contact with the patient’s blood or open tissues. This has led to
the terminology “exposure-prone procedures,” first coined by the CDC
in 1991 (5). Characteristics of exposure-prone procedures include
digital palpation of a needle tip in a body cavity or the
simultaneous presence of the HCW’s fingers and a needle or other
sharp instrument or object in a poorly visualized or highly confined
anatomical site (5). There have been no reported HBV transmissions
related to dental or oral surgery since the implementation of
universal precautions in 1987. Additionally, four of the
dentists/oral surgeons associated with outbreaks returned to
practice with their practices modified to include the routine use of
gloves (13,15,17,18). These observations highlight the importance
and effectiveness of education of the HCWs and the use of gloves in
preventing the transmission of BBPs in the dental setting.
Until 1997, all HCWs associated with HBV transmissions who were
tested were HBeAg positive, which is associated with higher levels
of circulating virus and greater infectivity
(2,15,16,19-24,26,28-30,32,33). This was identified as a marker for
HCWs who should refrain from performing exposure-prone procedures
(5,25). Since that time, there have been several reported
transmissions involving physicians who were HBeAg negative,
documenting that they may also transmit infection (25,31,34).
Detailed investigations of the surgeons in these transmissions
revealed that all carried a precore HBV mutant (25,31,34). This
mutation, located in the genome just before the gene that codes for
the core protein, prevents expression of the e antigen (34). The
mutation does not interfere with the replication of infectious virus
and some individuals with this precore mutant will have high levels
of circulating HBV DNA (25). It is not known what proportion of
HBeAg-negative carriers have the precore mutant, nor whether this
mutation is more or less likely to be associated with nosocomial
transmissions (25).
The ability to accurately measure the serum HBV DNA level might
allow a more precise determination of the degree of infectivity of
carriers. In-house assays of blood from five HBeAg-negative surgeons
found the lowest level of HBV DNA to cause infection was 2.5 x 105
copies per ml (25,34). Based on this, it has been suggested that the
cutoff HBV DNA level below which an HBeAg-negative carrier would
become non-infectious would probably be around 104 HBV DNA copies
per ml (38). It should be noted that the performance characteristics
of some commercial assays may not detect this level of viremia (38).
More recent look-back surveys of patients exposed to infected
surgeons have provided an estimate of transmission risk ranging from
0.5% to 13% (2,25,31,34). Risk factors for infection have not been
identified, but can be speculated to include the host’s health,
immune system and vaccine status, as well as the route of infection,
volume of inoculum, HBV DNA level, and strain pathogenicity (38).
Human immunodeficiency virus
In four serosurveys (7,10,39,40), the overall prevalence of HIV
infection among HCWs ranged from 0.4% to 0.7% and was similar for
medical and dental workers. Given the smaller risk for transmission
of HIV compared to HBV, it is not surprising that HIV prevalence is
substantially lower than HBV in HCWs. Similarly, it would be
expected that the rate of transmission from HIV-infected HCWs to
patients would be extremely low. In 1990, the CDC reported that a
Florida dentist with AIDS may have infected one of his patients in
the course of dental surgery (3). The public reaction to this was
unprecedented and focussed attention on the issue of HCWs infected
with BBPs. In the end, the CDC, through its epidemiological and
molecular investigations, concluded that the Florida dentist had
infected six of his patients in the course of their dental care
(41,42). The precise mode of HIV transmission to these patients
could not be identified and likely never will be.
The Florida dental case was particularly a mystery given the number
of prior and subsequent look-back investigations that failed to
identify HIV transmission from infected HCWs to patients (43-47). In
1995, the CDC published information on investigations of 64
HIV-infected HCWs that had been reported to them (48). HIV test
results were available for 22,171 patients of 51 of the 64 HCWs.
Thirty-seven of these 51 workers had no seropositive patients among
the 13,063 tested. While there were 113 seropositive patients for
the remaining 14 HCWs, epidemiological and laboratory follow-up
failed to etiologically link HCW and patient.
In 1999, a study from France (49) provided evidence that an
HIV-infected orthopedic surgeon may have transmitted HIV to one of
his patients during surgery. The patient, a 67-year-old woman with
no other HIV risks, had undergone a difficult replacement of a total
hip prosthesis with bone graft in 1992 and removal of the prosthesis
in 1993. She tested HIV negative in 1992 and positive in 1994. The
surgeon’s and patient’s viruses, although similar, displayed a 15.2%
difference, which was attributed to mutational changes between the
time of infection and testing. The surgeon reported both frequent
opportunities for blood exposures (as frequently as once a week) and
actual blood exposures. He often tightened suture wires with his
fingers, sometimes tied sutures with the needle still attached,
sometimes directed the needle with his fingers, and used digital
palpation of the needle tip during the placement of bone pins. Since
1983, he routinely double-gloved for operations and changed gloves
after needlestick injuries or procedures longer than 1.5 h. While
this report is evidence of the potential for HIV transmission from
an infected HCW to his or her patient under certain situations, it
must be viewed in the context of an overall extremely low risk and
one that should be preventable by safer techniques for handling
instruments, manipulating sutures and closing wounds (50).
Hepatitis C
Various studies have placed the prevalence of HCV in HCWs at between
1.4% and 2.0%, which is comparable to the rate in the general
population (7,10,51-53). Within the disciplines, however, some
groups have a higher prevalence for HCV, suggesting that there
are some occupations that carry a higher risk than others. In two
studies in the United States (52,53) there was a higher rate of HCV
in oral surgeons (2.0% and 9.3%) than other dentists (0.7% and
0.97%).
The epidemiology of HCV transmission from infected HCW to patient is
very similar to that of HBV. During a prospective study of the
efficacy of HCV serological assays in preventing transfusion-related
HCV infection, investigators identified two patients who developed
acute hepatitis C in relation to open-heart surgery (4). It was
subsequently determined that these two, and at least three other
patients, probably acquired their infection from a cardiac surgeon
with hepatitis C. The surgeon reported experiencing about 20
percutaneous injuries per 100 procedures, most often in the course
of tying the wires during closure of the sternum. He also reported
two percutaneous injuries with sharp objects and needles per 100
procedures, for which he would remove the instrument from the field
and change gloves. Since that time, there has been another report of
transmission of HCV to a patient after cardiothoracic surgery (54)
and two reports of transmission to patients during gynecologic
surgery (55,56). In two of these studies (54,56), all patients
exposed to the infected surgeons through exposure-prone procedures
were requested to undergo serological testing. No further
transmissions were identified, and the overall infection rate was
0.36% for cardiothoracic surgery (54) and 0.04% for gynecologic
surgery (56). Similar to the situation with occupational risk,
nosocomial transmissions through exposure to an infected HCW are
substantially lower than with HBV.
In addition to these cases linked to exposure-prone procedures
performed by an infected surgeon, there is one report of HCV
transmission from an anesthesiology assistant to five patients (57).
Investigation of this outbreak revealed that the infected HCW
usually did not wear gloves during procedures such as placement
of arterial and venous catheters and intubation, and had a weeping,
uncovered wound on one of his fingers. Other infections-control
breaches among staff were identified, including needle recapping,
inconsistent glove use and frequent use of multidose vials. This
outbreak highlight the importance of basic infection control in
preventing the nosocomial transmission of BBPs.
Guidelines for the Prevention of bloodborne pathogen Transmission
from health care worker to Patient
In 1991, the CDC published recommendations for preventing the
transmission of HIV and HBV to patients during exposure-prone
invasive procedures (5). They defined exposure-prone procedures
as including digital palpation of a needle tip in a body cavity or
the simultaneous presence of the HCW’s fingers and a needle or other
sharp instrument or object in a poorly visualized or highly confined
anatomical site and recommended that HCWs infected with HIV or
HBV (and HBeAg positive) should not perform such procedures
unless they sought counsel from an expert review panel. They also
stipulated that infected HCWs who continued to perform
exposure-prone procedures notify prospective patients. Mandatory
testing of HCWs for BBPs was not recommended. No recommendations
to restrict professional activity of HCV-infected HCWs currently
exist in the United States (58).
In the United Kingdom, HCWs who are HIV, HCV, and HBV (and HBeAg
positive) are not allowed to participate in exposure-prone
procedures (59-61). HBV carriers who are HBeAg negative undergo
quantitative viral load measurement. If the level is less than 103
copies per ml, they may continue to perform exposure-prone
procedures provided they are not associated with a nosocomial
transmission (59).
Health Canada published recommendations for HIV- and HBV-infected
HCWs in 1992, updating them to include HCV in 1995 and 1996 (6). Any
HCW with an infectious disease that could put a patient at risk was
encouraged to seek medical evaluation by his or her primary care
physician, who in turn was to seek advice on risk for transmission
through a consultation mechanism, which was not clearly defined.
To further clarify the management of HCWs infected with a BBP,
updated recommendations were published in 1998 following a consensus
conference held in November 1996 (6). Exposure-prone procedures
were expanded to include repair of major traumatic injuries or major
cutting or removal of oral or perioral tissue, including tooth
structures. The recommendations covered a number of areas,
including the importance of basic infection-control practices in
preventing the transmission of BBPs, preventing blood exposures in
the health care setting, immunizing and screening of HCWs, and risk
management (eg, trace-back and look-back activities) after an
infected HCW has practice modifications imposed. There were more
explicit guidelines about referral to an expert panel and the
composition of such panels. The panel’s mandate would be to assess
the transmission risk to patients posed by the infected HCW during
exposure-prone procedures and make recommendations on the HCW’s
practice (6). Mandatory testing was not recommended. Rather, it
remained an ethical obligation of HCWs performing exposure-prone
procedures to know their serological status and self-report to the
profession’s regulatory body.
The recommendations made in the 1998 Health
Canada report were not supported by the Canadian medical and dental
associations (6). Their major concerns appear to relate to mandatory
immunization and postimmunization serological testing of HCWs who
perform exposure-prone procedures, and HCW loss of privacy and
autonomy. However, several provincial physician regulatory bodies
have established expert panels to provide guidance to infected HCWs.
Continued discussion at the provincial level on how best to minimize
the risk of transmission of BBPs from infected HCW to patient is
anticipated. While the data are somewhat limited, there is a body of
literature to guide expert panels in their deliberations.
Unfortunately, there remains no consistent and readily accessible
opportunity for retraining the HCW whose practice is limited because
of infection with a BBP. While certain disability insurance plans
will provide coverage for non-disabled physicians whose practices
are limited because of infection with a BBP, their practices have to
be restricted by regulations approved by an appropriate governmental
authority, hospital board, or licensing authority for them to access
their benefits. Work needs to be done on facilitating physicians’
ethical obligations to report infection with a BBP if they perform
exposure-prone procedures
Nurse
anesthetist has license revoked for five years, has to pay $99,000 fine
Hill receives maximum penalty
01/31/03
By Tom Blakey
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OKLAHOMA CITY — The Oklahoma Board of Nursing unanimously approved a
consent order at Thursday’s board hearing, revoking nurse anesthetist
Jim Hill’s license for five years and ordering him to pay a $99,000 fine
within 30 days.
The order represented the maximum penalties under Oklahoma statutes.
Nursing Board members, in light of the Hill case, requested that
legislation be enacted to remove the five-year limit.
“Unfortunately, that won’t be done in time to affect this case,” said
Kim Glazier, executive director of the Nursing Board. However, the board
“can reject his reinstatement every five years,” Glazier said.
Hill, 55, was charged by the Nursing Board with failure to use proper
infection control techniques and adequately care for patients while
practicing at the Norman Regional Hospital Pain Management Clinic,
leading to the contraction of hepatitis C by 38 patients, and hepatitis
B by 10 patients, at Norman Regional Hospital between May 1999 and June
2002.
The board had first considered the matter at its Nov. 21 board
hearing, and rejected a consent order at the time that called for Hill
to surrender his license and pay a $61,000 fine.
The consent order agreed to Thursday called for Hill’s license to be
revoked, rather than surrendered. At the Nov. 21 hearing, Nursing Board
President Karen Fletcher said the board was “uncomfortable taking the
action as the consent order states.” The issue is one of surrender
versus revocation, Fletcher said.
“The difference is the language,” said Betty Smelser, Nursing Board
nurse investigator. “Mr. Hill was willing to surrender his license, but
the board rejected that and made a decision to revoke it.”
The $99,000 fine was based on recent figures released by the state
Health Department, and calculated by multiplying the known number of
patients tested for hepatitis C (750) by the $100 maximum fine, or
$75,000, added to the number of patients at Norman Regional diagnosed
with hepatitis C (38), multiplied by $500 (the maximum five-day, maximum
$100 fine), or $19,000; added to the number of patients at Norman
Regional diagnosed with hepatitis B (10), multiplied by $500 (the
maximum five-day, maximum $100 fine), or $5,000.
Hill and his attorneys did not appear at the board’s public hearing,
conducted Thursday at the Airport Holiday Inn Conference Center in
Oklahoma City.
Fletcher read the complaint at the outset of the proceedings, saying
Hill “regularly engaged in the practice of reusing the same needle and
syringe to inject anesthetic medications such as Versed, Fentanyl and
Propofol, to patients through their existing heparin locks …”
A heparin lock is a device used to keep an IV catheter from clotting
between infusions.
Board attorney Charles Green read Hill’s written response to the
amended complaint, saying, in part, that Hill “never intentionally
exposed any patients to a risk of harm and never thought he was placing
any patient at risk by his anesthesia techniques. (Hill) did not believe
that there was any potential for the upstream back flow of blood to
contaminate the needles or syringes he was using.”
The board voted unanimously to accept the consent order, which had
been reached among Hill’s attorneys Michael McMillin and Stephen
Peterson, Nurse Investigator Smelser and Nursing Board staff.
“There’s no way to describe the anger I felt when I heard (Hill’s
statement),” Barbara Burlingame said after the hearing. “How can he be a
nurse and not know you’re not supposed to re-use a needle?”
Burlingame became sick last April, and, because of tests showing her
liver enzymes were “off the wall,” had her gall bladder removed. ”We
weren’t worried about hepatitis — there was no way I could’ve been
exposed,” Burlingame said.
Meanwhile, Burlingame’s gastroenterologist at Norman Regional
Hospital, Dr. Phillip Bird, noticed six of his patients, including
Burlingame, were exhibiting signs of hepatitis C. Bird plotted the
hospital’s Pain Center as the common denominator among the patients, and
hospital and health department officials launched an investigation
leading to the discovery of the hepatitis C outbreak.
“Five years is not enough — I hope he never gets his license back,”
Burlingame said.
Reporter Tom Blakey covers city government and can be reached at
366-3540 or via e-mail at
tblakey@normantranscript.com
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