Hepatitis A Virus Infection Clinical Description of HAV Infection
HAV infection is usually acquired by the fecal-oral route, produces a self-limited disease that does not result in chronic infection or long-term liver disease, and usually produces symptoms of acute viral hepatitis after an average incubation period of 28 days (range: 15-50 days). Signs and symptoms usually last less than 2 months, although 10-15% of symptomatic persons have prolonged or relapsing disease lasting up to 6 months (Glikson, Galun, Oren, Tur-Kaspa, & Shouval, 1992). Peak infectivity occurs during the 2 weeks prior to onset of jaundice or elevation of liver enzymes, when the concentration of virus in stool is highest (Fiore et al., 2006). Persons with chronic liver disease who acquire hepatitis A are at increased risk for fulminant hepatitis (Vento et al., 1998).
Following the implementation of routine hepatitis A vaccination of children, overall hepatitis A rates have declined approximately 75% from 1990-1997 to 2004 (Wasley, Samandari, & Bell, 2005; Fiore et al., 2006). In 2004, the rate of hepatitis A case reports was 1.9 cases per 100,000 population (Fiore et al., 2006). The prevalence of HAV infection among persons aged >6 years in the United States was estimated to be 31.1% based on data from the National Health and Nutrition Examination Survey III conducted in 1988-1994 (Bell et al., 2005).
In the United States, the majority of cases of hepatitis A occur through person-to-person transmission during communitywide outbreaks (Bell et al., 1998; Fiore et al., 2006). HAV transmission can occur through close personal contact (e.g., household contact, sexual contact, drug use, or children playing), and contaminated food or water (e.g., infected food-handlers or raw shellfish). The most frequently reported source of infection (12-26%) is household or sexual contact with a person with HAV infection. Other risk groups include injection and non-injection drug users and men who have sex with men (MSM). Approximately 50% of persons with hepatitis A have no source identified for their infection.
Up to 15% of nationally reported hepatitis A cases occurred among persons reporting drug use or MSM behaviors (Fiore et al., 2006). In some communities, hepatitis A outbreaks involving users of injected and noninjected metham-phetamine have accounted for approximately 30% of reported cases (Bell et al., 1998; Van Beneden et al., 1998; Hutin, Bell, et al., 1999; Fiore et al., 2006). Transmission has been documented to occur from parenteral blood exposure (e.g., blood transfusion or injection-drug use) (Bower, Nainan, Han, & Margolis, 2000). However, the majority of transmission among users of illicit drugs is believed to occur through fecal contamination of drug paraphernalia and subsequent percutaneous inoculation, as well as from close personal contact (Hutin, Sabin, et al., 1999).
Hepatitis A outbreaks among MSM are frequently reported, and cyclic outbreaks occur in urban areas of the United States (Henning, Bell, Braun, & Barker, 1995; CDC, 1998b). HAV-infected MSM report more frequent oral-anal contact, longer duration of sexual activity, and a larger number of sex partners than persons without serologic evidence of infection (Corey & Holmes, 1980; Coutinho et al., 1983; Katz, et al., 1997; Stokes, Ferson, & Young, 1997).
Although inmates are at risk for hepatitis A because of close personal contacts, sexual behaviors, and injection drug use, no hepatitis A outbreaks have been reported from correctional settings. Seroprevalence studies have found prevalence of prior HAV infection among incarcerated persons (22-39%) to be similar to age-adjusted prevalence rates in the general U.S. population (Weinbaum, Lyerla, & Margolis, 2003; Fiore et al., 2006). Employment in a correctional setting has not been identified as a risk factor for HAV infection.
Hepatitis B Virus Infection
HBV is a bloodborne pathogen, transmitted by percutaneous or permucosal (e.g., sexual) exposure to infectious blood or body fluids (e.g., semen or saliva). HBV circulates in high titers in the blood and lower titers in other body fluids (e.g., semen, vaginal fluid, or saliva), and is approximately 100 times more infectious than HIV and 10 times more infectious than HCV (CDC, 2001c).
Acute hepatitis B develops in approximately 30-50% of adults at the time of initial infection and is characterized by anorexia, nausea, vomiting, and often jaundice. The risk of progression to chronic infection varies with age, being highest among young children and infants (30-90%) and lowest among adolescents and adults (2-6%) (Lok & McMahon, 2001).
Persons with chronic HBV infection serve as the primary source of infection for others (McQuillan et al., 1999; CDC, 2005). The majority of persons with chronic HBV infection are asymptomatic, and one third have no evidence of liver disease, despite high levels of viral replication (Lee, 1997). Chronic HBV infection can lead to cirrhosis and HCC. Lifetime risk of death from chronic liver disease or HCC is 15-25% (Beasley, Hwang, Lin, & Chien, 1981; Beasley, 1988; Chang et al., 1997; McMahon, 1997; McMahon, Holck, Bulkow, & Snowball, 2001). Rates of progression to cirrhosis and HCC are approximately 25% for persons who acquire infection during childhood and 15% for persons who acquire infection at older ages. Other factors that influence rates of progression include: HBeAg status; coinfection with HDV, HIV, HCV; and alcohol abuse (Rizzetto, 1983; McMahon, 1997; Ockenga et al., 1997; Zarski et al., 1998; Monto & Wright, 2001; Gao, 2002). HBV-related liver disease and HCC cause approximately 4000-5000 deaths in the United States annually (CDC, unpublished data, 2002).
An estimated 4.9% of the civilian, noninstitutionalized U.S. population has serologic evidence of past or present HBV infection, and 0.4-0.5% have chronic infection (McQuillan et al., 1999; CDC, 2005). Overall prevalence of HBV infection differs among racial/ethnic populations and is highest among persons who have immigrated from areas with a high endemicity of HBV infection (e.g., Asia, Pacific Islands, Africa, and the Middle East) (Coleman, McQuillan, Moyer, Lambert, & Margolis, 1998). Prevalence of infection among blacks is four times that among whites (11.9% versus 2.6%) (McQuillan et al., 1999).
With the implementation of a comprehensive hepatitis B vaccination strategy since 1991, the incidence of acute hepatitis B has declined 78% during 1990-2005 from 8.5 to 1.9 per 100,000 population (CDC, 2006b). The rate of acute hepatitis B varies by age, sex, and race; the highest rates occur among persons aged 25-44, and males have higher rates than females. Disease incidence continues to be the highest among blacks, the lowest rate was observed among Hispanics whose rate dropped below that of non-Hispanic whites for the first time in 2003.
Sexual contact is the predominant mode of HBV transmission among adults (Goldstein et al., 2002). In a sentinel surveillance project including six U.S. counties during 2001-2004, 30% of persons with acute hepatitis B reported having multiple sexual partners and 24% were MSM (Williams et al., 2005). In addition, injection drug use was reported by 13% of the acute hepatitis B cases and 40% of the persons with acute hepatitis B had no identifiable risks for hepatitis B infection. The percentage of cases reporting occupational exposure to blood continues to be low (approximately 0.5%) as a result of routine hepatitis B vaccination of health care workers and use of standard precautions to prevent exposure to bloodborne pathogens (CDC, 2006b).
Despite laws prohibiting sex between residents of correctional systems (Gaiter & Doll , 1996), 2-30% of inmates have sex while incarcerated (Nacci & Kane, 1983; Decker, Vaughn, Brodie, Hutcheson, & Schaffner, 1984; Tewksbury, 1989; Saum, Surratt, Inciardi, & Bennett, 1995). Only two state prison systems and five city or county correctional systems make condoms available to adult inmates and detainees for use in their facilities (Vermont, Mississippi, New York City, Philadelphia, San Francisco, Washington, DC, Los Angeles). Arrested adults also have a high prevalence of illicit drug use; in 2004 inmate surveys, 83% of state prisoners and 79% of federal prisoners reported past drug use, and 56% of state prisoners and 50% of federal prisoners reported using drugs in the month before their offense (Mumola & Karberg, 2006). Among jail inmates, drug use in the month before incarceration was reported by 55%, and injection-drug use (IDU) was reported by 18% (Wilson, 2000; http://www.ojp. usdoj.gov/bjs/pub/pdf/sdatji02.pdf). IDU during incarceration has been reported by 3-28% of adult inmates (Decker et al., 1984; Zimmerman, Martin, & Vlahov, 1991; CDC, 2001a; Khan et al., 2002). Although certain correctional systems offer substance-abuse treatment and education programs, demand usually exceeds program capacity (Stephan, 1997), and there appear to be no comprehensive risk-reduction programs available within correctional facilities.
Measured prevalence of serologic markers for current or past HBV infection among prison inmates has ranged from 13% to 47%, with variation by region. Prevalence is higher among women (37-47%) than men (13-32%) (Koplan, Walker, & Bryan, 1978; Decker et al., 1984; Hull et al., 1985; Smith, 1986; Tucker et al., 1987; Barry, Gleavy, Herd, Schwingl, & Werner, 1990; Ruiz et al., 1999; Weinbaum et al., 2003). Chronic HBV infection prevalence was 1.0-3.7% among prison inmates in various studies, 2-6 times the national prevalence estimate of 0.4-0.5% (Koplan et al., 1978; Bader, 1983; Kaufman, Faiver, & Harness, 1983; Decker et al., 1984; Bader, 1986; Tucker et al., 1987; Smith et al., 1991; Ruiz et al., 1999; Lopez-Zetina, Kerndt, Ford, Woerhle, & Weber, 2001). The few studies of HBV infection among jail inmates found the prevalence to be similar to that in prisons, ranging from 16% to 21% (Solomon, Flynn, Muck, & Vertefeuille, 2004; Hennessey et al., 2006).
While the majority of HBV infections among incarcerated persons are acquired in the community, incidence rates within correctional facilities have ranged from 0.8% to 3.8% per year (Decker et al., 1984; Hull et al., 1985; Khan et al., 2002;
CDC, 2004a). In one state prison, after identification of a single case of acute hepatitis B, serologic testing identified new HBV infections in 1.2% of the inmate population and serologic testing of susceptible inmates 1 year later identified an additional 3.8% newly infected inmates (CDC, 2001a; Khan et al., 2002). During a 3^-year follow-up period, 92 new HBV infections were identified, with patients housed in multiple facilities, suggesting widespread ongoing transmission throughout the prison system (Khan et al., 2005). As another indication of the risk for HBV transmission, 5.6% of cases with acute hepatitis B reported to CDC's Sentinel Counties Study of Viral Hepatitis have a history of incarceration during the disease incubation period (Goldstein et al., 2002). HBV transmission in the prison setting can occur through sexual activity, IDU, and percutaneous exposures that are not apparent, as it does in households where persons with chronic HBV infection reside (Peters, Purcell, Lander & Johnson, 1976; Bernier et al., 1982).
On release, susceptible inmates are often at increased risk for infection because they resume high-risk behaviors. A study of recidivist women reported an HBV infection seroconversion rate of 12.2/100 person-years between incarcerations (Macalino et al., 1999), compared with an estimated incidence of 0.03/100 person-years for the U.S. population (Weinbaum et al., 2003).
HCV, a bloodborne pathogen, is most efficiently transmitted by direct percutaneous exposure to infectious blood. Of persons newly infected with HCV, only 20-30% have symptoms of acute hepatitis (Aach et al., 1991; Alter et al., 1991; CDC, 1998a). Chronic infection develops in approximately 75-85% of persons infected as older adults (age >45) and in 50-60% of persons infected as juveniles or young adults (Alter & Seeff, 2000).
The majority of persons with chronic HCV infection are asymptomatic, and approximately 30% have no evidence of liver disease based on serum aminotrans-ferase levels. Among chronically infected persons, evidence of chronic liver disease develops in 70% of those infected as adults (Alter & Seeff, 2000). The risk for progression to cirrhosis varies by age at infection with persons infected as older adults at greater risk of progression than persons infected as juveniles or younger adults. Clinical progression is also accelerated by alcohol intake, chronic coinfection with HBV, and male sex (Alter & Seeff, 2000). Coinfection with HIV increases HCV viral loads, the rate of progression to fibrosis and cirrhosis, and liver-related mortality (Sulkowski, Mast, Seeff, & Thomas, 2000). HCC develops among 1-5% of persons with chronic hepatitis C (CDC, 1998a).
Using data from the National Health and Nutrition Examination Survey (NHANES) conducted during 1999-2002, an estimated 4.1 million persons (1.6%) in the civilian, noninstitutionalized U.S. population have been infected with HCV, of whom approximately 3.2 million (1.3%) are chronically infected (Armstrong et al., 2006). Men had a higher prevalence of HCV infection than women (2.1% versus 1.1%) and blacks had a higher prevalence of HCV infection than whites (3.0% versus 1.5%). When considering age, the highest prevalence was among those aged 40-49 which is consistent with a 1990 survey that reported the highest prevalence among those aged 30-39 (Alter et al., 1999).
Substantial or repeated percutaneous exposure to blood (e.g., IDU, exposure to clotting factor concentrates that did not undergo viral inactivation, and transfusions from HCV-positive donors) is the single most important risk factor for HCV infection. Of persons aged 20-59 who were anti-HCV-positive participating in the 1999-2002 NHANES, 48% reported a history of IDU (Armstrong et al., 2006). Data from the early 1990s found HCV antibody prevalence among persons who had been injecting 1 year or less of 77-89% (Thomas et al., 1995; Garfein, Vlahov, Galai, Doherty, & Nelson, 1996). More recent reports have found HCV antibody prevalence from 27% to 38% among injection-drug users less than 30 years of age (Garfein et al., 1998; Hahn et al., 2002, Thorpe et al., 2002). Incidence rates remain high, from 9% to 34% per year (Garfein et al., 1998; Hagan et al., 2001; Hahn et al., 2002; Thorpe et al., 2002; Des Jarlais et al., 2003, 2005).
Moderate prevalence (10%) has been reported among long-term hemodialysis patients, and lower prevalence is reported among persons with high-risk sexual practices (5%) and health care workers (1-2%) (CDC, 1998a). HCV is not transmitted efficiently through occupational exposure to blood. The risk of acquiring HCV infection from a contaminated needle stick is <2%, and transmission rarely has been documented from mucous membrane or nonintact skin exposures (CDC, 2001c).
Incidence of new HCV infections has been declining since the late 1980s, largely the result of a decrease in infections among injection-drug users. The majority of new HCV infections continue to occur in adult age groups (persons >25 years of age) with the greatest decline in incidence among 25- to 39-year-olds, historically the age group with the highest rates of infection. In this age group, incidence has declined by 92% from 1992 to 0.4/100,000 in 2004 (CDC, 2006b). Blacks and whites have the same incidence of new infection (0.2/100,000); rates among males (0.3/100,000) and females (0.2/100,000) are also similar. No association has been found between newly acquired HCV infection and military service, medical, surgical, or dental procedures, tattooing, acupuncture, ear piercing, or foreign travel (Alter et al., 1982, 1989). If transmission from such exposures does occur, the frequency has been too low to detect. However, results from seroprevalence studies of noninstitutionalized populations have been variable (Alter, 2002). Although one small study of IDUs suggested an increased risk for both HBV and HCV infection among those tattooed while in prison (Samuel, Doherty, Bulterys, & Jenison, 2001), limited studies have not confirmed this finding (CDC, 2001a; Bair et al., 2005; Samuel et al., 2001).
Despite the decrease in incidence among injection-drug users, the major risk factor for HCV infection remains IDU, which accounts for 60% of newly acquired infections (Garfein et al., 1996; Alter, 1997; CDC, 1998a; Williams et al., 2000; Garfein, Williams, Monterroso, Valverde, & Swartzendruber, 2000; Murrill et al., 2002). Among injection-drug users, HCV is transmitted by sharing syringes, needles, or other drug paraphernalia contaminated with the blood of an infected person (Koester & Hoffer, 1994; Heimer, Khoshnood, Jariwala-Freeman, Duncan, & Harima, 1996; Hagan et al., 1999). In studies conducted in the 1980s, approximately 80% of newly initiated injection-drug users were infected with HCV within 2 years (Thomas et al., 1995; Garfein et al., 1996; Lorvick, Kral, Seal, Gee, & Edlin, 2001). More recent studies indicate that the rate of HCV acquisition has slowed and approximately one-third of injection-drug users are infected within 2 years after initiating
IDU. Nonetheless, incidence among IDUs remains high at 10-15%/year (Hagan et al., 1999; Garfein et al., 2000; Thorpe, Ouellet, Levy, Williams, & Monterroso, 2000; Diaz et al., 2001).
Inmates are at risk for HCV infection due to past IDU, and other percutaneous exposures (e.g., tattoos, bites, and abrasions) with the potential to transfer infectious blood and transmit bloodborne pathogens are also common in correctional facilities (Gershon et al., 1999; Hessl, 2001; Khan et al., 2002). Among prison inmates, 16-41% have serologic evidence of HCV infection, and 12-35% have chronic HCV infection; rates vary by geographic region (Vlahov, Nelson, Quinn, & Kendig, 1993; Ruiz et al., 1999; Alter et al., 1999; Spaulding, Greene, Davidson, Schneidermann, & Rich, 1999; Weinbaum et al., 2003). Similar prevalence (10-35%) has been detected among jail inmates (Baillargeon et al., 2003; Solomon et al., 2004; Hennessey et al., 2006). Most HCV-infected inmates have a history of IDU. In a Wisconsin study of 1148 inmates, among the 310 (27%) with a history of IDU and serologic evidence of HBV infection or biochemical evidence of liver disease, 91% were determined to be anti-HCV-positive (Weinbaum et al., 2003). Among HCV-positive entering jail inmates in Massachusetts, 85% reported needle-sharing, prior drug use, or a history of hepatitis (Weinbaum et al., 2003).
The risk of HCV acquisition during incarceration is not well-established. The only published study to examine the incidence of HCV infection among prison inmates reported a rate of 1.1 infections/100 person-years of incarceration among males (Vlahov et al., 1993).
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