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Health Care–Acquired Hepatitis
Historical Background
The potential for bloodborne transmission of hepatitis B first was noted in 1885, when Lurman described jaundice in factory workers who had received smallpox vaccine prepared from “human lymph.” More reports appeared in the subsequent decades as use of vaccines derived from human serum became more common. In addition, more frequent use of phlebotomy equipment, insulin therapy, and intramuscular injection of antibiotics all led to small outbreaks of jaundice, which were ascribed to a transmissible “icterogenic” agent.
By the late 1940s, studies to clarify the modes of transmission were undertaken. Central to these was the use of human volunteers, who were given putatively infectious material intradermally, intranasally, or by ingestion of feces, and then observed for development of jaundice. From these landmark reports arose our current understanding of the basic principles of transmission of infectious hepatitis (hepatitis A) and serum hepatitis (hepatitis B).
The first report of occupational disease in health care workers (HCWs) was provided by Leibowitz and colleagues, who described jaundice in a blood bank nurse with numerous needle pricks on her hands and fingers. A spate of similar reports followed, describing occupationally acquired hepatitis among nurses, blood bank workers, phlebotomists, house staff, and others. Soon, the workers’ compensation boards of certain states ruled that viral hepatitis was a compensable occupational hazard. Improved understanding of routes of transmission, more comprehensive and rigorous infection control including needle disposal, and, for hepatitis B, vaccination of workers at risk have helped to decrease, but not eliminate, this occupational risk. A corollary risk, that of transmission of infection from infected HCWs, particularly surgeons, to nonimmune patients, has been described for hepatitis B and hepatitis C.
Current Epidemiology of Health Care–Associated Hepatitis B and C Outbreaks in the United States
A health care–associated outbreak of hepatitis is defined as two or more cases that are epidemiologically and/or genetically linked. Since 2008, The Centers for Disease Control and Prevention (CDC) has maintained a Web-based inventory of health care–associated cases and outbreaks of hepatitis B and C. This source described 59 outbreaks affecting more than 450 people that were investigated between 2008 and 2016 ( Fig. 303.1 ). In addition, 18 (15 hepatitis C and 3 hepatitis B) sporadic cases of patient-to-patient health care–associated transmission of hepatitis B and C were recognized during this time.
Health care–associated outbreaks of hepatitis mostly have been recognized in nonhospital settings, with a growing trend in long-term care facilities and ambulatory areas, especially outpatient hemodialysis units. Practices associated with transmission of hepatitis reveal a shift in etiology: syringe reuse and needlestick injuries have less commonly been the cause, and more cases have been traced to other health care exposures. These include improper use of blood glucose monitoring fingerstick devices on multiple patients, contamination of saline flush and multidose vials, and breaches in disinfection and sterilization of medical equipment.
Hemodialysis-related outbreaks of hepatitis C continue to occur, with most being attributed to environmental contamination or unsafe practices during vascular access or medication preparation or administration. Diversion of medication, wherein a practitioner personally administers an intravenous narcotic and then reuses the remainder of the vial of medication or the needle in a patient or patients, is also increasingly recognized as a source of transmission. At least five diversion-related outbreaks have been recognized in the United States since 2009, including one from a traveling medical technician that spread across eight states, resulting in over 11,000 exposed individuals with 45 confirmed infections. This outbreak led to a criminal conviction of the source HCW.
Fecal-Oral Transmission
Hepatitis A
HCWs are not considered to be at a higher occupational risk for hepatitis A, because nosocomial outbreaks and transmission from patient to care provider have been infrequent. The Advisory Committee on Immunization Practices (ACIP) does not recommend routine vaccination of HCWs to protect against hepatitis A. The rare reports of nosocomial transmission have largely occurred in pediatric units and nurseries. The preponderance of hepatitis A outbreak reports in neonatal settings is due to the asymptomatic nature of infection in infants and young children and prolonged shedding ; the disease in index cases often goes unrecognized until secondary cases in adult contacts have occurred. Rare outbreaks in adults have been related to high physical dependency or diarrhea or fecal incontinence.
Although dominantly an enterically transmitted infection, hepatitis A can rarely be acquired via blood and platelet transfusion from donors with incubating infection ; in addition, a single transplant-associated case has also been described. Tertiary transmission of hepatitis A from a child who had initially contracted hepatitis A via multi–visceral organ transplant eventually led to infection in 2 of 42 home health nurses who provided direct care to the child.
Postexposure prophylaxis (PEP) by administration of intramuscular immune globulin to contacts has been used effectively for many years ( Table 303.1 ). Although not specifically assessed in health care–related exposures, vaccination within 2 weeks has been shown to be 80% to 90% effective in preventing clinical hepatitis A among immunocompetent adults younger than 40 years. Vaccine was successfully used in two eligible nurses in the transplant recipient–related outbreak. Since 2000, Canadian guidelines have routinely recommended vaccine as the preferred PEP for nonimmunocompromised patients older than 1 year. In United Kingdom, immune globulin is recommended to be given in conjunction with vaccine only for healthy adults older than 50 years, and those with chronic liver disease or an immunocompromising condition, regardless of age.
TABLE 303.1
Risk of Transmission, Prevention, and Postexposure Management of Health Care Workers With Occupational Exposure to Hepatitis Viruses
| HEPATITIS | RATE a | PREVENTION | POSTEXPOSURE MANAGEMENT |
|---|---|---|---|
| A | 10%–30% | Vaccine not recommended routinely for HCWs except in outbreak setting | Vaccine within 2 weeks of exposure. Immunoglobulin plus vaccine may be considered for HCWs with chronic liver or immunocompromising conditions. |
| B | HBeAg − source: 3% HBeAg + source: 22%–31% |
HBV vaccination | HCWs with previous response to vaccine need no additional postexposure treatment regardless of level of exposure and time since vaccination. HCWs with no history of vaccination or nonresponders should receive HBIG and vaccine (for those with no history) as soon as possible after the exposure. HCWs with unknown response after primary series should have anti-HBs titers checked.
If anti HBs titers cannot be readily obtained, first dose of HBIG should be administered. |
| C | 3% | Immune globulin not recommended; see Chapter 154 for treatment | No role for direct-acting antivirals. Immediate baseline testing for hepatitis C antibody, then HCV RNA if antibody positive. If source patient confirmed with HCV infection, or with unknown status, repeat HCV RNA three weeks after exposure. |
| Delta | Unknown; outbreaks described only in dialysis units | HBV vaccination | Segregate HBsAg + dialysis patients by delta antibody status. |
| E | Unknown | Standard precautions |
HBeAg, hepatitis B e antigen; HBIG, hepatitis B immune globulin; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HCV, hepatitis C virus; HCWs, health care workers.
a Rate of transmission from outbreak or needlestick exposure.
Hepatitis E
First identified as a cause of acute hepatitis in Kashmir, India, hepatitis E virus (HEV) is primarily transmitted via contaminated water. The virus has caused several large-scale outbreaks among refugees and other displaced populations. Person-to-person spread among household contacts has been demonstrated only in resource-constrained settings, where transmission is attributed to poor sanitation and to communal hand-washing and eating practices.
In Europe, indigenous infection from zoonotic contact or acquisition via meat products (undercooked pork, pork liver sausage, game meat, and shellfish) is on the rise, with predominantly genotype 3a infections. Currently in Europe, infections due to HEV are at least as common as hepatitis A among patients hospitalized with acute hepatitis. Approximately half of all HEV cases are autochthonous in origin because risk of acquisition is strongly influenced by regional farming and dietary practices. Certain areas in eastern Japan, southwestern France, and the Netherlands have exceedingly high seropositivity rates as a result of these factors. A detailed description of the epidemiology of hepatitis E can be found in Chapter 178 .
Seroprevalence of Hepatitis E in Developed Countries and Risk of Bloodborne Transmission
Seroprevalence of hepatitis E in the United States is estimated to be around 6.25%, with the highest rates in the Midwest. Genotypes 3 and 4 prevail among the sporadic locally acquired infections. Based on population estimates from the National Health and Nutrition Examination Survey (NHANES), seroprevalence rates in US adults older than 30 years declined from 20% (1988–1994) to 8.4% (2009–2010); a decrease in seropositivity was seen among all age groups within this time period. Overall, anti-HEV immunoglobulin G (IgG) prevalence decreased from 9.6% to 5.2%.
Several assessments of blood donors in the United States have concluded that the transmission risk of HEV is minimal. Screening of blood products for HEV is not currently recommended in the United States. Blood donor screening data from several European countries have also demonstrated variable rates of hepatitis E viremia, ranging from 0.02% to 0.08% with an associated transmission risk of 0.04% ( Table 303.2 ). Some European countries have adopted universal screening of blood products for hepatitis E. A detailed discussion on this topic can be found in Chapter 304 .
TABLE 303.2
Country-Specific Rates of Hepatitis E RNA Prevalence Among Screened Blood Products and Associated Risk of Transmission
| COUNTRY (YEAR) | UNIT SCREENED | SAMPLES SCREENED | HEV RNA PREVALENCE | POSTTRANSFUSION HEV IN RECIPIENT | COMMENT |
|---|---|---|---|---|---|
| Netherlands (2013) | Mini-pools | 59,474 | 0.076% | NA | Estimated duration of viremia in donors = 68 days |
| Germany (2012) | Mini-pools | 16,125 | 0.08% | NA | |
| Spain (2015) | Individual | 9998 | 0.03% | NA | |
| Denmark (2016) | Individual | 25,637 | 0.04% | 7/11 recipients without detectable viremia | Low copy numbers in donors (13 IU/mL) |
| Ireland (2016) | Individual | 24,985 | 0.02% | NA | Universal screening implemented |
| France (2014) | Mini-pools | 53,234 | 0.045% | NA | |
| United Kingdom (2014) | Mini-pools | 225,000 | 0.035% | 42% attack rate | Universal screening implemented |
| Australia (2017) | Pools | 74,131 | 0.001% | ||
| United States (2013) | Individual | 1930 | 0% | No transmission | |
| United States (2016) | Individual | 18,829 | 0.01% | NA | Low copy numbers in positive donors |
| United States (2017) | Mini-pools | 128,028 | 0.002% | NA | Type 3a infections with low copy numbers |
HEV, Hepatitis E virus; NA, not applicable.
Other Nosocomial Transmission
Non–transfusion-related nosocomial HEV transmission is rare; an outbreak in Pakistan attributed to sharing of parenteral equipment affected 18 individuals, with 7 confirmed cases. A single case of patient-to-patient spread of hepatitis E via contaminated hospital environment was suspected in a French hospital in which the donor patient with detectable virus in blood and stool had an overlapping stay with the case patient, who developed acute infection 3 weeks later. The strains were closely related by genotypic analysis.
Hepatitis B
Epidemiology
Hepatitis B was the first bloodborne disease recognized to pose an occupational hazard. In the prevaccine era, the prevalence of hepatitis B virus (HBV) among HCWs was 10-fold greater than in the general population. An early review found a preponderance of cases among pathologists, laboratory workers, and blood bank workers. Later studies added dentists, physicians, nurses, and laboratory and dialysis staff to the list of HCWs with increased risk.
Vaccine to prevent HBV infection became available in the United States in 1982. Introduction of the currently used recombinant HBV vaccine improved vaccine acceptance. Since 1991, it has been recommended as a universal childhood vaccination. In 1987, concern about occupational acquisition of human immunodeficiency virus (HIV) led the US Department of Labor, in conjunction with the Department of Health and Human Services, to recommend universal precautions to protect against exposure to body fluids. Four years later, the Occupational Safety and Health Administration published the federal Bloodborne Pathogens Standard, which went into effect in early 1992. This document mandated that HCWs with potential exposure to blood or other potentially infectious materials should be offered the hepatitis B vaccine series free of charge, should demonstrate immunity to hepatitis B, or should formally decline vaccination. In order to identify nonresponders and to intervene early, postvaccination serologic testing is recommended for HCWs prone to blood and body fluid exposures. Compliance with these recommendations has resulted in a 98% reduction in occupationally acquired hepatitis B, although rare cases continue to occur. Based on a survey conducted by the CDC between 2005 and 2010, 203 cases of hepatitis B were reported among HCWs; among these, only 40% were possibly related to occupational exposures. Complete vaccination with three or more doses could be confirmed for 35 HCWs infected with hepatitis B, 1 had immune titers, and others were nonresponders or without additional information.
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