The prevalence of hepatitis C virus infection in the United States, 1988 through 1994.

BACKGROUND: Because many persons with chronic hepatitis C virus (HCV) infection are asymptomatic, population-based serologic studies are needed to estimate the prevalence of the infection and to develop and evaluate prevention efforts. METHODS: We performed tests for antibody to HCV (anti-HCV) on serum samples from 21,241 persons six years old or older who participated in the third National Health and Nutrition Examination Survey, conducted during 1988 through 1994. We determined the prevalence of HCV RNA by means of nucleic acid amplification and the genotype by means of sequencing. RESULTS: The overall prevalence of anti-HCV was 1.8 percent, corresponding to an estimated 3.9 million persons nationwide (95 percent confidence interval, 3.1 million to 4.8 million) with HCV infection. Sixty-five percent of the persons with HCV infection were 30 to 49 years old. Seventy-four percent were positive for HCV RNA, indicating that an estimated 2.7 million persons in the United States (95 percent confidence interval, 2.4 million to 3.0 million) were chronically infected, of whom 73.7 percent were infected with genotype 1 (56.7 percent with genotype 1a, and 17.0 percent with genotype 1b). Among subjects 17 to 59 years of age, the strongest factors independently associated with HCV infection were illegal drug use and high-risk sexual behavior. Other factors independently associated with infection included poverty, having had 12 or fewer years of education, and having been divorced or separated. Neither sex nor racial-ethnic group was independently associated with HCV infection. CONCLUSIONS: In the United States, about 2.7 million persons are chronically infected with HCV. People who use illegal drugs or engage in high-risk sexual behavior account for most persons with HCV infection.

Prevalence of hepatitis B virus infection in the United States: the National Health and Nutrition Examination Surveys, 1976 through 1994.

OBJECTIVE: Data from 2 National Health and Nutrition Examination Surveys (NHANES), NHANES II (1976-1980) and NHANES III (1988-1994), were analyzed to examine trends in the prevalence of hepatitis B infection in the United States. METHODS: Serum specimens were tested for markers of hepatitis B virus infection, and risk factors were determined from questionnaires. RESULTS: The overall age-adjusted prevalence of hepatitis B virus infection was 5.5% (95% confidence interval [CI] = 4.8, 6.2) in NHANES II, as compared with 4.9% (95% CI = 4.3, 5.6) in NHANES III. In both surveys, Black participants had the highest prevalence of infection (NHANES II, 15.8%; NHANES III, 11.9%). No differences in infection were found in the major racial groups between surveys, except for a decrease among those older than 50 years. Black race, increasing number of lifetime sexual partners, and foreign birth had the strongest independent associations with hepatitis B virus infection. CONCLUSIONS: Testing of participants in 2 national surveys demonstrates no significant decrease in hepatitis B virus infection, despite the availability of hepatitis B vaccine.

Hepatitis C: Part II. Prevention counseling and medical evaluation.

An estimated 3.9 million Americans are infected with hepatitis C virus (HCV), and most do not know that they are infected. This group includes persons who are at risk for HCV-associated chronic liver disease and who also serve as reservoirs for transmission of HCV to others. Because there is no vaccine to prevent HCV infection and immune globulin is not effective for postexposure prophylaxis, prevention of HCV infection is paramount. Patients who are at risk of exposure to HCV should be advised on steps they might take to minimize their risk of infection. Patients who are infected with HCV should be counseled on ways to prevent transmission of HCV to others and to avoid hepatotoxins. They should also be examined for liver disease and referred for treatment, if indicated.

Hepatitis C: Part I. Routine serologic testing and diagnosis.

Hepatitis C, which is caused by the hepatitis C virus (HCV), is a major public health problem in the United States. HCV is most efficiently transmitted through large or repeated percutaneous exposures to blood. Most patients with acute HCV infection develop persistent infection, and 70 percent of patients develop chronic hepatitis. HCV-associated chronic liver disease results in 8,000 to 10,000 deaths per year, and the annual costs of acute and chronic hepatitis C exceed $600 million. An estimated 3.9 million Americans are currently infected with HCV, but most of these persons are asymptomatic and do not know they are infected. To identify them, primary health care professionals should obtain a history of high-risk practices associated with the transmission of HCV and other bloodborne pathogens from all patients. Routine testing is currently recommended only in patients who are most likely to be infected with HCV.

The diverse patterns of hepatitis A epidemiology in the United States-implications for vaccination strategies.

Hepatitis A is the most frequently reported vaccine-preventable disease in the United States. Hepatitis A incidence and risk factors during 1983-1995 were examined among cases reported to the study's Sentinel Counties: Denver County, Colorado; Pierce County, Washington; Jefferson County, Alabama; and Pinellas County, Florida. Of 4897 serologically confirmed cases, 611 patients (13%) were hospitalized and 9 (0.2%) died. The average incidence was 14.7/100, 000 (range, 0.6-100.7/100,000, depending on county and year). The frequency of reported sources of infection varied by county, but the largest single group overall (52%) did not report a source. During 3-year communitywide outbreaks in Denver (1991-1993) and Pierce (1987-1989) Counties, rates increased 4- and 13-fold, respectively, and increased in all age, racial/ethnic, and risk groups. During communitywide outbreaks, hepatitis A is not limited to specific risk groups; sustained nationwide reductions in incidence are more likely to result from routine childhood vaccination than from targeted vaccination of high-risk groups.

Incidence of hepatitis B virus infection in the United States, 1976-1994: estimates from the National Health and Nutrition Examination Surveys.

Precise estimates of the incidence of hepatitis B virus (HBV) infection are required to assess the impact of immunization and other prevention strategies in the United States. Race- and age-specific prevalence data obtained from the second and third National Health and Nutrition Examination Surveys (NHANES II, 1976-1980, and NHANES III, 1988-1994) were used to estimate the annual incidence of HBV infection by catalytic modeling. During the period covered by NHANES II, an estimated 323,462 persons were infected annually, and 334,863 were infected annually during the period covered by NHANES III. No statistically significant declines in prevalence of HBV infection occurred between the two surveys, a period during which hepatitis B vaccination targeted only limited numbers of high-risk adults.

Hepatitis A through E.

Viral hepatitis is a term commonly used for several clinically similar, yet etiologically and epidemiologically distinct, diseases. Five human hepatitis viruses have been identified. Hepatitis A, B, C, and D are endemic in the United States; hepatitis E is rarely reported in the United States, and most U.S. cases are seen in persons who have traveled to areas where hepatitis E. is endemic. Hepatitis A and E are transmitted by the fecal-oral route; hepatitis B, C, and D are blood-borne diseases. Hepatitis A and B have been recognized as separate entities since the early 1940s and can be diagnosed by serologic tests. Tests are available to detect the antibody to hepatitis C and D virus; no commercial test is available to diagnose hepatitis E. Hepatitis A, B, and D can be prevented by vaccine, but no vaccines are available for hepatitis C or E.

The importance of preventing hepatitis C virus infection among injection drug users in the United States.

Injection drug use is the single most important risk factor for acquiring hepatitis C virus (HCV) infection. Injection drug users acquire this infection rapidly after initiating injection practices, and up to 90% of them are chronically infected with HCV. HCV infection is a major cause of chronic liver disease, and persons infected with HCV are at risk for chronic hepatitis, cirrhosis, and primary hepatocellular carcinoma, and they risk transmitting HCV infection to others. Preventive measures for HCV infection are limited. The heterogeneous nature of HCV and its ability to undergo rapid mutation appear to prevent the development of an effective neutralizing immune response, obstructing development of a vaccine. Prevention of HCV infection must rely on educational and programmatic efforts aimed at preventing drug use, providing substance abuse treatment for persons who inject illicit drugs, and encouraging safer injection practices. These efforts should include messages about the risk and prevention of all blood-borne pathogens, including HCV, hepatitis B virus, and human immunodeficiency virus.

Hepatitis C.

Hepatitis C virus (HCV) has emerged as a major cause of chronic liver disease worldwide. The widespread endemicity of HCV infection is the result of a combination of factors, including those related to the genetic diversity of the virus and the host response and those related to the specific settings and behaviors that have facilitated transmission. Most people who contract HCV infection become persistently infected, and the mechanism by which persistent infection is established seems to be related to the lack of development of an effective neutralizing immune response. The magnitude of the spread of HCV infection primarily is related to specific risk factors for transmission. The most important human behavior related to the transmission of HCV has been injection drug use, which in many developed countries has been the leading source of HCV infection during the past 20 to 30 years. The recognition of the clinical importance of HCV infection has resulted in a substantial amount of attention and resources rapidly directed toward developing new and improved therapies. The perception, however, of the public health importance of HCV infection is still limited. Despite the knowledge that injection drug use is the major source of HCV infection in the United States, this message has not been included in prevention and treatment programs, and the resources needed to support strong public health programs have yet to be identified.

Acute non-A-E hepatitis in the United States and the role of hepatitis G virus infection. Sentinel Counties Viral Hepatitis Study Team.

BACKGROUND: Little is known about the relation of the newly discovered hepatitis G virus (HGV) to the cause and clinical course of acute and chronic viral hepatitis. METHODS: We selected patients from a surveillance study of acute viral hepatitis in four U.S. counties who had acute disease during 1985 to 1986 or 1991 to 1995. Serum samples were tested for HGV RNA by the polymerase chain reaction. RESULTS: HGV RNA was detected in 4 of 45 patients with a diagnosis of non-A-E hepatitis (9 percent), 23 of 116 patients with hepatitis C (20 percent), 25 of 100 patients with hepatitis A (25 percent), and 32 of 100 patients with hepatitis B (32 percent) (P<0.05 for the comparison of hepatitis B with hepatitis non-A-E or C). The clinical characteristics of the acute illness were similar for patients with HGV alone and those with hepatitis A, B, or C with or without HGV infection. During a follow-up period of one to nine years, chronic hepatitis did not develop in any of the patients with HGV alone, but 75 percent were persistently positive for HGV RNA, as were 87 percent of those with both hepatitis C and HGV infection. The rates of chronic hepatitis were similar in patients with hepatitis C alone (60 percent) and those with both hepatitis C and HGV infection (61 percent). CONCLUSIONS: The evidence from this surveillance study does not implicate HGV as an etiologic agent of non-A-E hepatitis. Persistent infection with HGV was common, but it did not lead to chronic disease and did not affect the clinical course in patients with hepatitis A, B, or C.

National surveillance of dialysis associated diseases in the United States--1994.

Dialysis centers in the United States were surveyed in 1994 regarding a number of hemodialysis associated diseases and practices. A total of 2,449 centers, representing 206,884 patients and 50,314 staff members, responded. In 1994, 99% of centers used bicarbonate dialysate as the primary method of dialysis, 45% used high flux dialysis, and 75% reused dialyzers. Hepatitis B vaccine had been administered to 31% of patients and to 80% of staff members. Acute infection with hepatitis B virus occurred in 0.1% of patients and was more likely to be reported by centers with lower proportions of patients vaccinated against hepatitis B virus and those not using a separate room and dialysis machine to treat hepatitis B surface antigen positive patients. The prevalence of antibody to hepatitis C virus was 10.5% among patients and 1.9% among staff members and varied according to geographic region. Pyrogenic reactions in the absence of septicemia were reported by 22% of centers and were most highly associated with dialyzer reuse. Human immunodeficiency virus infection was reported to be present in 1.5% of patients; 37% of centers provided hemodialysis to one or more patients infected with human immunodeficiency virus.

National surveillance of dialysis associated diseases in the United States, 1993.

To determine trends in a number of hemodialysis associated diseases and practices, the Centers for Disease Control and Prevention, in collaboration with the Health Care Financing Administration, performed a mail survey of 2,304 chronic hemodialysis centers in the United States in 1993. By the end of 1993, at least three doses of hepatitis B vaccine were administered to 29% of patients and 76% of staff at responding centers. Hepatitis B surface antigen was present at low frequency in patients (incidence = 0.1%, prevalence = 1.2%) and staff members (incidence = 0.2%, prevalence = 0.3%). The 1993 incidence of hepatitis B virus infection among patients was higher at centers that accepted hepatitis B surface antigen positive patients but did not use a separate room and dialysis machine for treatment of these patients, government and profit (versus nonprofit) centers, and centers in four End Stage Renal Disease Networks. The prevalence of antibody to hepatitis C virus was 9.7% among patients and 1.6% among staff members. Pyrogenic reactions in the absence of septicemia were reported by 21% of centers and associated with use of high flux dialysis. Human immunodeficiency virus infection was known to be present in 1.5% of patients; 34% of centers reported providing hemodialysis to one or more human immunodeficiency virus infected patients.

National surveillance of dialysis associated diseases in the United States, 1992.

To determine trends in a number of hemodialysis associated diseases and practices, the Centers for Disease Control and Prevention, in collaboration with the Health Care Financing Administration, completed a mail survey of chronic hemodialysis centers in the United States in 1992. Of 2,321 centers surveyed, 2,170 (93%) representing 170,028 patients and 43,535 staff members responded. In 1992, 2,049 (94%) centers used bicarbonate dialysate as the primary method of dialysis, 765 (35)% used high flux dialysis, and 1,569 (72%) reused dialyzers, continuing the trends toward increased use of these methods. Central (subclavian or jugular) venous catheters were used in > or = 1 patient as permanent vascular access for hemodialysis at 69% of dialysis centers. Hepatitis B surface antigen was present at low frequency in patients (incidence = 0.1%, prevalence = 1.2%) and staff members (incidence - 0.03%, prevalence = 0.3%). Among centers that had > or = 1 hepatitis B surface antigen positive patient, the incidence of hepatitis B virus infection was lower in those centers that used a separate room for dialysis of patients positive for hepatitis B surface antigen. From 1991 to 1992, reported hepatitis B vaccine coverage increased from 17% to 24% among patients and from 56% to 69% among staff members; in absolute terms, these were the largest single year increases since introduction of hepatitis B vaccine. The prevalence of antibody to hepatitis C virus was 8.1% among patients and 1.6% among staff members. Pyrogenic reactions in the absence of septicemia were reported by 19% of centers and associated with use of high flux dialysis. New dialyzer syndrome was reported by 24% of centers, most frequently by centers using regenerated cellulose or cuprophan membranes. Human immunodeficiency virus was known to be present in 1.5% of patients; 34% of centers reported providing hemodialysis to one or more patients infected with HIV.

Blood exposure and the risk of hepatitis B virus infection in firefighters.

The risk of infection with bloodborne pathogens among public safety workers is not well defined. This survey assessed personal and occupational risk factors among uniformed fire department employees by a self-administered questionnaire and hepatitis B virus (HBV) infection status by serologic testing. Overall, 46 (7.8%) of 592 employees had past or current hepatitis B virus infection. Employees reporting blood contact with skin had been infected more often than employees without this exposure (11% vs 5.8%, prevalence ratio = 1.9, 95% confidence interval, 1.1, 3.3). Prevalence of infection did not differ by age, years on the job, or job duties. The adjusted prevalence of hepatitis B virus infection among male employees (4.5%) was not significantly different than the prevalence in American men (6.8%) (P = .17). Although the overall risk of hepatitis B virus infection is not greater among fire department employees than the general population, blood contact with skin may elevate this risk.

National surveillance of dialysis associated diseases in the United States, 1991.

To determine trends in a number of hemodialysis associated diseases and practices, the Centers for Disease Control and Prevention in collaboration with the Health Care Financing Administration performed a mail survey of chronic hemodialysis centers in the United States in 1991. Of 2,123 centers surveyed, 2,046 (96%), representing 155,877 patients and 40,298 staff members, responded. The 1991 survey found that certain hemodialysis practices are increasing in frequency, including use of bicarbonate dialysate and high-flux dialysis and reuse of disposable dialyzers (in 1991, 71% of centers reused dialyzers). Hepatitis B surface antigen (HBsAg) was present at low frequency in patients (incidence = 0.2%, prevalence = 1.3%) and staff (incidence = 0.04%, prevalence = 0.3%). Among centers that had > or = HBsAg positive patient, the incidence of hepatitis B virus (HBV) infection was lower in those centers that used a separate room for dialysis of HBsAg positive patients. Reuse of dialyzers, blood lines, transducer filters, or dialyzer caps was not associated with an increased risk of acquiring HBV infection among either patients or staff. Antibody to HBsAg was present in 21% of patients and 53% of staff, and was significantly related to levels of hepatitis B vaccine coverage. Pyrogenic reactions in the absence of septicemia were reported by 20% of centers and associated with the reuse of dialyzers. Human immunodeficiency virus (HIV) was known to be present in 1.2% of patients; 29% of centers reported providing hemodialysis to one or more HIV infected patients.

National surveillance of hemodialysis associated diseases in the United States, 1990.

To determine trends in several hemodialysis associated diseases and practices, the Centers for Disease Control (CDC), in collaboration with the Health Care Financing Administration (HCFA), performed a mail survey of chronic hemodialysis centers in the United States in 1990. Of 1,995 centers surveyed, 1,882 (94%) representing 140,608 patients and 36,907 staff members responded. As in recent years, the 1990 survey found that certain hemodialysis practices are increasing in frequency, including treatment of water with reverse osmosis and deionizer units; use of bicarbonate dialysate and high-flux dialysis; and reuse of disposable dialyzers (in 1990, 70% of centers reused dialyzers). Hepatitis B surface antigen (HBsAg) was present at low frequency in patients (incidence, 0.2%; prevalence, 1.2%) and staff (incidence, 0.04%; prevalence, 0.3%). Antibody to hepatitis B surface antigen was present in 20% of patients and 58% of staff, and was significantly related to levels of hepatitis B vaccine coverage. Pyrogenic reactions in the absence of septicemia were reported by 20% of centers and were associated with use of high-flux dialyzer membranes and reuse of dialyzers (particularly in centers where the maximum number of reuses was 40 or more). Septicemia among hemodialysis patients was reported by 49% of centers. Twenty-six percent of centers reported providing hemodialysis for patients infected with human immunodeficiency virus (HIV), and 1.1% of dialyzed patients had known HIV infection.

A survey of hepatitis B surface antigen-positive blood donors: degree of understanding and action taken after notification.

All blood donors in the United States are tested for hepatitis B surface antigen (HBsAg) upon donation; if the test result is positive, the primary method of notification is by letter. To assess the effectiveness of this notification methods in stimulating HBsAg-positive donors to seek medical care and take preventive measures, 54 donors who tested HBsAg-positive on donation at the American Red Cross Blood Services. Atlanta Region, from January 1987 to July 1989 were interviewed. Thirty-nine donors (72%) had sought medical care after notification; the only motivating factor was that the letter told the donor to consult with his or her physician. Compared with donors who did not seek medical care, donors who did so were more likely to understand that the blood test was abnormal or that they were infected, and they were more likely to understand how hepatitis B virus is transmitted and that a vaccine is available. The differences were not significant, however. Of those donors who sought medical care, less than half received appropriate recommendations for protection of contacts, and of those who did, only one-third received prophylaxis. In-person and telephone interviews with donors, revision of the notification letter, and hepatitis B education programs targeted at medical care providers are suggested.