Prevalence and screening costs of hepatitis C virus among Ugandan blood donors.

BACKGROUND: Screening donated blood for hepatitis C virus (HCV) is important for HCV prevention and is routinely practiced in North America and Europe. However, in many African countries little is known about HCV prevalence or cost-effectiveness of HCV antibody (anti-HCV) screening. METHODS: We investigated 2592 plasma specimens collected consecutively from blood donors in central Uganda in 1999. Routine screening by the blood bank included human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and syphilis. To assess HCV prevalence and cost-effectiveness of testing, specimens were additionally tested for anti-HCV IgG by enzyme immunosorbent assay (EIA). Specimens repeatedly reactive (RR) on EIA were tested with a recombinant immunoblot assay (RIBA). RESULTS: Overall, 107 (4.1%) specimens were HCV EIA RR. Fifteen EIA RR specimens (0.6%, 95% confidence interval = 0.3-0.9%) were RIBA positive and 47 (1.8%) were RIBA indeterminate. Most (80%) RIBA-positive specimens were non-reactive for HIV, HBsAg, and syphilis. RIBA positivity was not associated with donor age, sex, number of donations, HIV, or HBsAg positivity. Costs of screening donors for anti-HCV by using EIA were estimated at US Dollars 782 per potential transfusion-associated HCV infection (exposure to RIBA-positive blood) averted. CONCLUSIONS: Current screening tests for other infections are ineffective in removing HCV-positive donations. Testing costs are considerable; cost-effectiveness of identifying HCV-infected donors will be critical in decision making about HCV screening in Uganda.

Hepatitis B vaccination rate of homeless children in Baltimore.

OBJECTIVE: To investigate the hepatitis B vaccination rate in homeless children 2 to 18 years old living in Baltimore City. METHODS: During a 21-month period, 250 children from homeless shelters were enrolled. RESULTS: The percent of children who had received 3 or more doses of hepatitis B vaccine was inversely related to age; 90% in 2- to 5-year-olds and 29% in 13- to 18-year-olds (P<0.0001). Seventy percent of 2- to 5-year-olds had at least some of their vaccine history recorded in the Baltimore Immunization Registry Program but the history was complete in only half. Forty-two percent of 13- to 18-year-olds had no hepatitis B vaccine doses recorded in any source; 49 per cent of 10- to 18-year-olds were either not immunized or had received only one hepatitis B vaccine dose. CONCLUSIONS: Hepatitis B vaccine coverage is high in homeless children up to 9 years of age, whereas the majority of homeless children 10 years of age and older are unprotected against hepatitis B virus infection. Tracking the vaccine records in homeless children is labor intensive. Better public health strategies to deliver hepatitis B vaccine to older homeless children are urgently needed.

Risk factors for HCV infection among blood donors confirmed to be positive for the presence of HCV RNA and not reactive for the presence of anti-HCV.

BACKGROUND: In 1999, NAT of blood donations was implemented to detect "window-period" infections. Blood donors who have confirmed NAT results positive for the presence of HCV in the absence of anti-HCV are likely to have been recently infected. Of over 26.8 million donations tested between March 3, 1999, and March 31, 2003, 810 were HCV-reactive by NAT. A subset of these donors was assessed for recent exposure risk. STUDY DESIGN AND METHODS: All anti-HCV- blood donors with reactive, unconfirmed HCV NAT results were invited to participate in a study that included an extensive demographic and risk questionnaire. Confirmed HCV+ cases were compared to HCV- (falsely positive) controls for histories of potential risk factors during the 6 months before donation. RESULTS: Recent injection drug use (IDU) was independently associated with HCV infection (29.2% vs. 0% of cases vs. controls, p < 0.001). In addition, likely sources were identified for three other cases (4.6%), including occupational exposure, sexual contact with an HCV-infected partner (who was an IDU), and perinatal exposure, none of which was known to the donors at the time of donation. Incarceration was independently associated with HCV infection among the group not reporting IDU and after removal of the three donors with likely sources of risk (14.6% vs. 1.3% of cases vs. controls, p < 0.001). CONCLUSIONS: A likely risk, primarily IDU, was found for 43 percent of HCV+ donors whose infections were identified solely by NAT. Because the maximum efficiency of the donor history questions may have been reached, NAT will continue to be an important measure to interdict recently infected blood donors.

Infection control in hemodialysis units.

Infectious complications of hemodialysis include bacterial infections caused by contaminated water or equipment, other bacterial infections (including vascular access infections), and bloodborne viruses (primarily the hepatitis B and C viruses). Infections caused by contaminated water and equipment can be prevented by a well-designed water-treatment system, routine cleaning and disinfection of system components, and routine bacteriologic monitoring of dialysis water and dialysis fluid. Standard precautions with additional measures recommended specifically for dialysis centers will prevent transmission of bacteria and viruses from patient to patient. These precautions include routine use of gloves, handwashing, and cleaning and disinfection of the external surface of the dialysis machine and other environmental surfaces. In addition, preventing transmission of hepatitis B virus infection requires vaccination of susceptible patients and staff, avoiding dialyzer reuse, and use of a dedicated room, dialysis machine, and staff members when treating patients chronically infected with this virus.

Prevalence and incidence of hepatitis C virus infection in the US military: a seroepidemiologic survey of 21,000 troops.

Because of a high prevalence of hepatitis C virus (HCV) infection (10-20%) among veterans seeking care in Department of Veterans Affairs (VA) hospitals, current US military forces were evaluated for HCV infection. Banked serum samples were randomly selected from military personnel serving in 1997 and were tested for antibody to HCV (anti-HCV). Overall prevalence of anti-HCV among 10,000 active-duty personnel was 0.48% (5/1,000 troops); prevalence increased with age from 0.1% among military recruits and active-duty personnel aged <30 years to 3.0% among troops aged >/=40 years. Prevalence among 2,000 Reservists and active-duty troops was similar. Based on sequential serum samples from 7,368 active-duty personnel (34,020 person-years of observation), annual incidence of infection was 2/10,000. Of 81 HCV RNA-positive troops for whom genotype was determined, genotypes 1a (63%) and 1b (22%) predominated, as in the civilian population. These data indicate that HCV infection risk among current military forces is lower than in VA studies and the general civilian population aged <40 years. The low level of HCV infection may be attributed to infrequent injection drug use in the military due to mandatory testing for illicit drugs prior to induction and throughout military service.

Incidence and prevalence of chlamydia, herpes, and viral hepatitis in a homeless adolescent population.

BACKGROUND: High rates of unprotected intercourse and illegal drug use have been reported among homeless adolescents. As a transient population with the potential to act as disease vectors from one location to another, incidence and prevalence of sexually transmitted infections in this population are of particular concern. GOAL: To assess a homeless adolescent population for incidence and prevalence of Chlamydia trachomatis, herpes simplex virus type 2, hepatitis B virus, hepatitis C virus, HIV, and psychosocial correlates of the acquisition of sexually transmitted infections. STUDY DESIGN: Longitudinal with assessments at baseline, 3 months, and 6 months (n = 536; 319 males and 217 females). RESULTS: Baseline prevalence of C trachomatis was 4.17% for males and 6.30% for females. Prevalence of herpes simplex virus type 2 was 5.73% for males and 12.50% for females. Hepatitis B virus and hepatitis C virus prevalences were 3.60% and 5.0%, respectively. HIV seroprevalence was 0.3%. The incidence of sexually transmitted infections was significantly higher among females than among males (16.7% versus 9.8%) and was associated with inconsistent condom use and, for females, number of partners and sex with older partners. Incident hepatitis B virus and hepatitis C virus infection rates were 3.44% and 6.61%, respectively; both were associated with injection drug use. CONCLUSIONS: Among females, the incidence of herpes simplex virus type 2 (> 25%) and C trachomatis (12%) was relatively high. Inconsistent condom use was the primary factor associated with a significantly greater risk of incident sexually transmitted infections. This was especially true for females with multiple partners. Homeless adolescents also are at high risk for hepatitis B virus and hepatitis C virus infection, primarily associated with self-reported injection drug use.

Management of occupational exposures to hepatitis C virus: current practice and controversies.

Unlike hepatitis B virus and human immunodeficiency virus, there currently are no immunization or chemoprophylactic interventions available to prevent infection after an occupational exposure to hepatitis C virus (HCV). A "Reality Check" session was held at the 4th Decennial International Conference on Nosocomial and Healthcare-Associated Infections to gather information on current practices related to management of occupational exposures to HCV, generate discussion on controversial issues, and identify areas for future research. Infection control professionals in attendance were knowledgeable in most issues addressed regarding the management of occupational exposures to HCV. Areas of controversy included the use of antiviral therapy early in the course of HCV infection and the appropriate administrative management of an HCV-infected healthcare worker.

Evaluation of the effectiveness of targeted lookback for HCV infection in the United States-interim results.

BACKGROUND: As part of a nationwide program to identify persons at increased risk for HCV infection, persons who received blood from donors who later tested positive for anti-HCV are being directly notified. STUDY DESIGN AND METHODS: In December 1999, all 198 blood collection establishments (BCEs) and 5442 hospital transfusion services (TSs) in the United States were surveyed by mailed questionnaire to evaluate their progress in carrying out this notification. RESULTS: Eighty-one percent of the BCEs and 64 percent of the TSs responded. After correcting for nonresponse, an estimated 98,484 components at potential risk for transmitting HCV, according to previous testing of multiantigen-screened donors, were identified nationwide, of which 85 percent had been transfused to recipients. Lookback for these recipients was completed for 80 percent, of whom 69 percent had died. Of those living, 78 percent were successfully notified. An estimated 49.5 percent of those notified were tested; 18.9 percent of those tested were anti-HCV positive, and 32 percent of that group knew they were positive before notification. On the basis of an 85.5 percent reported completion rate for component notifications back through 1988, an estimated 1520 persons will have been newly identified as anti-HCV-positive when lookback related to multiantigen screening of donors is completed. CONCLUSION: Targeted lookback related to previous multiantigen screening of donors will identify <1 percent of the estimated 300,000 HCV-positive persons in the United States who may have acquired their infection via blood transfusion.

Epidemiology of hepatitis C: geographic differences and temporal trends.

Hepatitis C Virus (HCV) infection appears to be endemic in most parts of the world, with an estimated overall prevalence of 3%. However, there is considerable geographic and temporal variation in the incidence and prevalence of HCV infection. Using age-specific prevalence data, at least three distinct transmission patterns can be identified. In countries with the first pattern (e.g., United States, Australia), most infections are found among persons 30-49 years old, indicating that the risk for HCV infection was greatest in the relatively recent past (10-30 years ago) and primarily affected young adults. In countries with the second pattern (e.g., Japan, Italy), most infections are found among older persons, consistent with the risk for HCV infection having been greatest in the distant past. In countries with the third pattern (e.g., Egypt), high rates of infection are observed in all age groups, indicating an ongoing high risk for acquiring HCV infection. In countries with the first pattern, injection drug use has been the predominant risk factor for HCV infection, whereas in those with the second or third patterns, unsafe injections and contaminated equipment used in healthcare-related procedures appear to have played a predominant role in transmission. Much of the variability between regions can be explained by the frequency and extent to which different risk factors have contributed to the transmission of HCV. Because different strategies are required to interrupt different patterns of HCV transmission, determining the epidemiology of HCV infection in areas where that information has not yet been assessed is critical for developing appropriate prevention programs.

The past incidence of hepatitis C virus infection: implications for the future burden of chronic liver disease in the United States.

Because chronic liver disease may develop many years after acute hepatitis C virus (HCV) infection, the past incidence of acute infections is a major determinant of the future burden of HCV-associated complications. We estimated past incidence of acute HCV infection using national seroprevalence data and relative age-specific incidence data from a sentinel counties surveillance system. Projections of the future prevalence of HCV-infected patients were derived from models that included an 85% drop in HCV infection incidence as observed for reported cases in the early 1990s. The models showed a large increase in the incidence of HCV infections from the late 1960s to the early 1980s. The degree of increase was dependent on the assumed rate of antibody loss; a model with 2.5% annual antibody loss showed annual incidence increasing from 45,000 infections (95% confidence interval [95% CI]: 0-110,000) in the early 1960s to 380,000 infections (95% CI: 250,000 to 500, 000) in the 1980s. Projections showed that although the prevalence of HCV infection may be declining currently because of the decline in incidence in the 1990s, the number of persons infected for >/=20 years could increase substantially before peaking in 2015. If the incidence of new HCV infections does not increase in the future, persons born between 1940 and 1965 will be at highest lifetime risk of acquiring the infection.

An outbreak of hospital-acquired hepatitis B virus infection among patients receiving chronic hemodialysis.

OBJECTIVE: To investigate a cluster of hepatitis B virus (HBV) infections between December 1995 and May 1996 among chronic hemodialysis patients in one county. SETTING: Two dialysis centers (A and B) and a hospital (C) in one county. PATIENTS: Six case-patients who were dialyzed in one of two centers, A and B, and had all been hospitalized between January and February 1996 at hospital C. METHODS: Patient 1, usually dialyzed in center A, sero-converted to hepatitis B surface antigen (HBsAg) in December 1995 and could have been the source of infection for the others, who seroconverted between March and April 1996. Two cohort studies were conducted: one among patients dialyzed in center A, to determine where transmission had occurred, and one among patients dialyzed at hospital C at the time patient 1 was hospitalized, to identify factors associated with infection. RESULTS: Four (15%) of the 26 susceptible patients dialyzed at center A became infected with HBV. Hospitalization at hospital C when patient 1 was hospitalized was associated with infection (P = .002). A cohort study of the 10 susceptible patients dialyzed at hospital C during the time patient 1 was hospitalized did not identify specific risk factors for infection. However, supplies and multidose vials were shared routinely among patients, providing opportunities for transmission. CONCLUSION: When chronic hemodialysis patients require dialysis while hospitalized, their HBsAg status should be reviewed, and no instrument, supplies, or medications should be shared among them.

Hepatocellular carcinoma not related to hepatitis B virus infection among Alaska natives.

Chronic infection with hepatitis B or C viruses is a common underlying condition in patients with hepatocellular carcinoma worldwide. We studied serum and liver tissue from a cohort of Alaska natives with hepatocellular carcinoma (HCC) for evidence of hepatitis B, C and G viral infection using conventional serological tests as well as the sensitive polymerase chain reaction. Evidence of HBV infection was found in 25 and possible HCV infection in two cases. Among the remaining 11 patients, four had a history of recent or remote alcoholism while seven had no recognizable risk factors for HCC. Only one was seropositive for HGV RNA and that was an individual with a history of alcoholism. Non-tumorous liver tissue was available for study in six of these seven cases. Histological features of chronic hepatitis were present in five. Thus, at least five of 38 (13%) Alaska natives with HCC appeared to have chronic hepatitis not related to HBV or HCV infection, suggesting the possibility of some form of previously unrecognized chronic liver disease predisposing to HCC.

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.

Strategies to prevent and control hepatitis B and C virus infections: a global perspective.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major causes of acute and chronic liver disease worldwide. Chronic infection with these viruses often leads to chronic liver disease, including cirrhosis or primary hepatocellular carcinoma. Both HBV and HCV are bloodborne viruses; however, HBV is transmitted efficiently by both percutaneous and mucosal exposures, and HCV is transmitted predominantly by percutaneous exposures. Because the relative importance of various modes of transmission of these viruses differs by country, the choice of specific prevention and control strategies depends primarily on the epidemiology of infection in a particular country. Comprehensive hepatitis B prevention strategies should include (1) prevention of perinatal HBV transmission, (2) hepatitis B vaccination at critical ages to interrupt transmission and (3) prevention of nosocomial HBV transmission. The prevention of hepatitis C is problematic because a vaccine to prevent HCV infection is not expected to be developed in the foreseeable future. From a global perspective, the greatest impact on the disease burden associated with HCV infection will most likely be achieved by focusing efforts on primary prevention strategies to reduce or eliminate the risk for transmission from nosocomial exposures (e.g. blood transfusion, unsafe injection practices) and high-risk practices (e.g. injecting drug use).

Protective effect of hepatitis B vaccine in chronic hemodialysis patients.

Hepatitis B virus (HBV) infection is a well-recognized risk in chronic hemodialysis patients. Although the risk has declined dramatically since the 1970s, outbreaks of HBV infection among these patients continue to occur. The Centers for Disease Control and Prevention (CDC) has recommended hepatitis B vaccination of hemodialysis patients since 1982; however, by 1996, only 36% of the approximately 200,000 US chronic hemodialysis patients had received the vaccine, perhaps in part because of doubts among dialysis personnel of its efficacy. We performed a case-control study to determine whether receipt of hepatitis B vaccine was associated with a decreased risk of acquiring HBV infection. We determined the vaccination status of all chronic hemodialysis patients at 98 US hemodialysis centers that reported patients with acute HBV infection on a nationwide mailed survey in 1995. A total of 111 hepatitis B surface antigen (HBsAg) positive case patients were compared with 12,500 control patients. Case patients were significantly less likely than control patients to have received hepatitis B vaccine (10.8% v 23.6%; odds ratio, 0.39; 95% confidence interval, 0.22-0.72). After stratifying by dialysis center to control for differing community and dialysis center risks of HBV infection, we found that the risk for HBV infection was 70% lower in vaccinated patients (adjusted odds ratio, 0.30; 95% confidence interval, 0.18-0.50). These results suggest that hepatitis B vaccine has a significant protective effect against acquiring HBV infection in chronic hemodialysis patients, and efforts should be expanded to increase the use of hepatitis B vaccine in this patient population.