The significance of 'anti-HBc only' in the clinical virology laboratory.

BACKGROUND: Isolated detection of hepatitis B core antibody (anti-HBc) in the absence of surface antigen (HBsAg) or antibody (anti-HBs) has been reported, particularly among individuals infected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). The significance of this phenomenon is unknown and it is unclear whether all individuals with such serological pattern need further molecular investigations. OBJECTIVES: To determine the prevalence of 'anti-HBc only' in samples referred to a clinical virology laboratory and to evaluate its significance and possible mechanisms. STUDY DESIGN: Samples identified as anti-HBc positive (389/4359, 8.9%) during an 11-month period were investigated for HBsAg, anti-HBs, anti-HCV and anti-HIV. 'Anti-HBc only' samples were tested for HBV DNA using a nested qualitative PCR. Viral loads were measured in samples with detectable HBV DNA and the DNA sequences were analysed. RESULTS: Of 379 samples with detectable anti-HBc, 155 (40.9%) were 'anti-HBc only'. HBV DNA was detected in 6/151 (4%), all of which had a viral load <400 copies per ml. Anti-HIV was found in 50/151 (33.1%) and anti-HCV in 14/151 (9.3%). Of these, only one of the HIV infected patients had detectable HBV DNA. Phylogenetic analysis of the HBV surface gene from three patients showed a variety of genotypes (A, E and G). One sequence had a mutation in codon 144, which has previously been reported to give false negative HBsAg results. CONCLUSIONS: 'Anti-HBc only' is a common phenomenon in the clinical virology laboratory but only a small proportion of samples had detectable HBV DNA. The presence of HBsAg mutants with possible false negative HBsAg test result is of concern. Samples with 'anti-HBc only' could be used to monitor the emergence of these mutants.     

No evidence of hepatitis B virus activity in patients with anti-HBc antibody positivity with or without anti-hepatitis C virus antibody positivity.

BACKGROUND: The serological pattern of anti-HBc antibody positivity without both, HBsAg and anti-HBs antibody positivity may be present in up to 4% of the population of Europe and the United States. OBJECTIVES: The aim of the present study was to determine the hepatitis B virus (HBV) activity by detection of serum HBV DNA in patients with anti-HBc antibody positivity only and with confirmed anti-hepatitis C virus (anti-HCV) antibody positivity or without anti-HCV antibody positivity. STUDY DESIGN: A total of 141 patients positive for anti-HBc antibodies only, were investigated on serum HBV DNA load. Patients were classified into two groups: patients with confirmed positive anti-HCV antibodies (group 1) and patients without anti-HCV antibodies (group 2). RESULTS: Demographic data of patient groups were similar. In 66 of 70 patients with anti-HBc antibodies and anti-HCV antibodies (group 1), serum HCV RNA was detected; the remaining 4 patients were HCV RNA negative but the presence of anti-HCV antibodies was confirmed by the line probe assay. In none of the patients, with anti-HBc antibodies and without anti-HCV antibodies (group 2), serum HCV RNA was detected. In none of the patients, serum HBV DNA was detected. CONCLUSION: In this study, serum HBV DNA could not be detected in patients with anti-HBc antibodies only. There seems to be no need for determination of serum HBV DNA in patients without clinical evidence of chronic liver disease. Nevertheless, it would be useful to test patients with progressive liver disease and those, which belong to high-risk groups such as hemophiliacs, intravenous drug abusers, patients on hemodialysis, and immunocompromised patients.     

Significance of isolated anti-HBc seropositivity by ELISA: implications and the role of radioimmunoassay.

Hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) are excellent markers for HBV infection and its immunity. The significance of isolated antibody to HBV core antigen (anti-HBc) seropositivity is not certain. To elucidate this, sera from 638 Chinese adult subjects, aged 18-52 years, seronegative for both HBsAg and anti-HBs, were tested for anti-HBc. Fifty-one (8%) were found to have an isolated anti-HBc seropositivity by ELISA, and all were negative for IgM-anti-HBc. The anti-HBc persisted in all subjects who attended follow-up for hepatitis B vaccination (n = 48) for a period of 8 months. These 48 subjects received 3 doses of hepatitis B vaccine (HB-VAX, 10 micrograms or 20 micrograms) at 0, 1, and 6 months: 72.9% developed a primary anti-HBs response (suggestive of a false-positive anti-HBc seropositivity), 4.2% developed an anamnestic or secondary anti-HBs response, and 22.9% did not develop an anti-HBs response. Increasing the cutoff point of the ELISA or reconfirmation with radioimmunoassay (RIA) reduced only a minor half of the false positives. This low specificity of anti-HBc ELISA/RIA, together with the high rate of anti-HBs response to hepatitis B vaccine, indicates that subjects with isolated anti-HBc seropositivity should be included in vaccination programs.     

Clinical significance of occult hepatitis B virus infection in chronic hepatitis C patients

Background/Aims

We investigated the frequency of occult hepatitis B virus (HBV) infection in anti-hepatitis C virus (HCV)-positive individuals and the effects of occult HBV infection on the severity of liver disease.

Methods

Seventy-one hepatitis B virus surface-antigen (HBsAg)-negative patients were divided according to their HBV serological status into groups A (anti-HBc positive, anti-HBs negative; n=18), B (anti-HBc positive, anti-HBs positive; n=34), and C (anti-HBc negative, anti-HBs positive/negative; n=19), and by anti-HCV positivity (anti-HCV positive; n=32 vs. anti-HCV negative; n=39). Liver biopsy samples were taken, and HBV DNA was quantified by real-time PCR.

Results

Intrahepatic HBV DNA was detected in 32.4% (23/71) of the entire cohort, and HBV DNA levels were invariably low in the different groups. Occult HBV infection was detected more frequently in the anti-HBc-positive patients. Intrahepatic HBV DNA was detected in 28.1% (9/32) of the anti-HCV-positive and 35.9% (14/39) of the anti-HCV-negative subjects. The HCV genotype did not affect the detection rate of intrahepatic HBV DNA. In anti-HCV-positive cases, occult HBV infection did not affect liver disease severity.

Conclusions

Low levels of intrahepatic HBV DNA were detected frequently in both HBsAg-negative and anti-HCV-positive cases. However, the frequency of occult HBV infection was not affected by the presence of hepatitis C, and occult HBV infection did not have a significant effect on the disease severity of hepatitis C.     

Prevalence of hepatitis B virus and hepatitis C virus in patients with human immunodeficiency virus infection in central China

Co-infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) with human immunodeficiency virus (HIV) has an adverse effect on liver disease progression. This study investigated the prevalence of HBV and/or HCV co-infection in HIV-infected patients in Central China. A total of 978 HIV-infected patients from Hunan Province were enrolled. HBV serum markers, anti-hepatitis-C-virus antibody (anti-HCV), HBV DNA, and HBV genotypes were analyzed. The prevalence of hepatitis B surface antigen (HBsAg) and anti-HCV in HIV-infected patients was 19.4 % and 62.4 %, respectively. The prevalence of anti-HCV in HIV-positive intravenous drug users was 93.6 %. Among HBsAg-positive patients, 88.1 % were found to have at least one HBV serum marker. The rates of HIV mono-infection, HBV/HIV dual infection, HCV/HIV dual infection, and HBV/HCV/HIV triple infection were 30.4 %, 7.2 %, 50.2 %, and 12.2 %, respectively. Antibody to HBsAg (Anti-HBs) was more common in anti-HCV-positive than anti-HCV-negative patients (53.3 % vs 40.2 %, P = 0.000), but isolated hepatitis B core antibody (anti-HBc) was more common in anti-HCV-negative than anti-HCV-positive patients (24.2 % vs 12.3 %, P = 0.000). Hepatitis B e antigen (HBeAg) and sexual transmission were independent risk factors for active HBV replication. Intravenous drug use and male sex were independent risk factors, but old age and presence of HBeAg were independent protective factors for anti-HCV. Co-infection of HBV and/or HCV with HIV infection is common in central China. HCV status is associated with anti-HBs and isolated anti-HBc in co-infected patients.     

Prevalence of parenterally transmitted hepatitis viruses in clinically diagnosed cases of hepatitis

Hepatitis B virus (HBV) is the most important causative agent of blood borne hepatitis in humans. Hepatitis D Virus (HDV) infection occurs either as a coinfection or superinfection in HBV carriers. Hepatitis C virus (HCV) is the major cause of transfusion non-A, non-B hepatitis and continues to be a major cause of human liver disease throughout the world. The present study was conducted on 70 clinically diagnosed cases of viral hepatitis to study the prevalence of parenterally transmitted viral hepatitis. The serum samples were tested for HBsAg, HBeAg, IgM anti-HBc, anti-HBe, anti-HCV and anti-HDV using separate ELISA kits. Of the 70 serum samples tested, 28 (40%) were positive for HBsAg out of which 3 (4.28%) were positive for HBeAg also. Five (7.1%) of the HBsAg positive cases tested positive for IgM anti-HBc also. HBsAg alone was found in 17 (24.28%) cases. The prevalence of anti-HCV was 3 (4.28%) in 70 cases. Thus early screening of clinically diagnosed cases of viral hepatitis is essential for establishing diagnosis and treatment to prevent long term sequelae.     

HCV genotype and "silent" HBV coinfection: two main risk factors for a more severe liver disease.

To evaluate whether HCV genotype and a "silent" HBV infection may be related to a more severe clinical presentation of liver disease, 205 anti-HCV/HCV-RNA positive, HBsAg/anti-HBs negative patients with chronic hepatitis (113 males and 92 females; median age 55 years, range 18-77), were studied on presentation at the Liver Unit from January 1993 to December 1997. Presence of serum anti-HBc, in the absence of HBsAg and anti-HBs, was considered a marker of "silent" HBV infection. Of the 205 patients, 134 had undergone percutaneous liver biopsy. Two main diagnosis groups were established: the mild liver disease group (76 patients), and the severe liver disease group (109 patients); 20 patients who had refused to undergo liver biopsy were not included in the clinical and virological evaluation because the diagnosis was uncertain. The prevalence of severe liver disease was similar in the genotype 1 and non-1 groups (61.3% of 98 patients with genotype 1 and 52.9% of 70 patients with a non-1 genotype). Instead, the 88 patients with "silent" HBV infection showed a higher percentage of severe liver disease than the 97 anti-HBc negative patients (72.7% vs. 46.4%, respectively: P < 0.0005). Of the 88 anti-HBc positive patients, the prevalence of those with severe liver disease was similar in the 32 cases with serum HBV-DNA as detected by PCR and in the 56 HBV-DNA negative (81.2% vs. 67.8%, P = 0.4). The relation between "silent" HBV infection and severe liver disease was observed both in genotype 1 and non-1 infected patients. Nevertheless, the anti-HBc negative patients infected by genotype 1 showed a severe liver disease more frequently than those infected by a non-1 genotype, with a difference that is significant to the statistical analysis (P < 0.05). The findings suggest that "silent" HBV infection in anti-HCV positive chronic hepatitis enhances the severity of the liver disease. Evidence was also found that in patients without "silent" HBV infection there is a correlation between the presence of HCV genotype 1 and the severity of liver disease.     

Dental care and spread of hepatitis B virus infection.

Sera from 576 healthy adults were tested for the hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) to evaluate the role of routine dental care as a factor in the spread of hepatitis B virus (HBV) infection. Serological evidence of prior HBV infection, manifested by acquisition of anti-HBs, was detected in 97 (16.8%) individuals, and 6 (1.0%) were identified to be asymptomatic HBsAg carriers. The anticipated correlations of HBsAg and anti-HBs with age, country of birth, and socioeconomic status were observed in the study population. However, prevalences of both HBsAg and anti-HBs were inversely related to the lifetime total of dental care visits. These findings indicated that, in a region in which the HBsAg carrier state and hepatitis B are prevalent, routine dental care is not identified as an important factor in the spread of HBV infection. While the results do not exclude the obvious possibility that cross-infections with HBV may occur during dental care in specific situations, they indicate that this mode of infection is exceptional.     

Isolated core antibody hepatitis B in sub-Saharan African immigrants

Chronic hepatitis B virus (HBV) infection is a major health problem in sub-Saharan Africa, where prevalence is > or =8%, and is increasingly seen in African immigrants to developed countries. A retrospective audit of the medical records of 383 immigrants from sub-Saharan Africa attending the infectious diseases clinics at the Royal Melbourne Hospital was performed from 2003 to 2006. The HBV, human immunodeficiency virus (HIV) and hepatitis C virus (HCV) serological results are reported, with a focus on the isolated core antibody HBV pattern (detection of anti-HBc without detection of HBsAg or anti-HBs). Two-thirds (118/174, 68%) of those tested had evidence of HBV infection with detectable anti-HBc. Chronic HBV infection (serum HBsAg detected) was identified in 38/174 (22%) and resolved HBV infection (both serum anti-HBs and anti-HBc detected) in 45/174 (26%). The isolated core antibody pattern was identified in 35/174 (20%), of whom only 1/35 (3%) had detectable serum HBV DNA on PCR testing, indicating occult chronic HBV (OCHB). Only 8/56 (14%) patients with negative anti-HBc had serological evidence of vaccination (serum anti-HBs detected). HIV infection was detected in 26/223 (12%). HCV antibodies were detected in 10/241 (4%), of whom 8 (80%) had detectable HCV RNA. Viral co-infection was detected in only 2/131 (1.5%) patients tested for all three viruses. The isolated core antibody HBV pattern was common among sub-Saharan African patients in our study. These patients require assessment for OCHB infection and monitoring for complications of HBV.     

Virological and clinical aspects of multiple hepatitis virus infections: preliminary data of an italian multicentre study

To evaluate the interference between HBV, HCV and HDV and the clinical impact of coinfection as compared with single HBV or HCV infection, we unrolled 618 HBsAg and/or anti-HCV positive subjects (337 with liver biopsy and 281 without liver biopsy) at their first observation at one of the seven Italian Liver Units from 1993 to 1997 (Padova, Rome, Sassari, Naples, Bari, Messina, Palermo). Serum HBV-DNA by dot-blot was found more frequently in patients with HBV infection alone (52% of 133 cases) than in those with HBV-HCV coinfection (28% of 64 cases, p<0.005) or in those with HBV-HDV-HCV coinfection (12% of 25 cases, p<0.0005) or with HBV-HDV coinfection (13% of 8 cases, p<0.05). We observed a higher prevalence of HCV-RNA positive cases in the patients with HCV infection alone (91.2% of 114 cases) than in those with HBV-HCV coinfection (64.5% of 62 cases, p<0.0001) or with HBV-HDV-HCV infection (19% of 21 cases, p<0.0001). These observations suggest a reciprocal inhibition of HBV and HCV genome in multiple hepatitis viral infection. A severe liver disease was more frequently observed in patients with HBV-HCV coinfection (66%) than in those with a single HBV infection (43%, p<0.05) or HCV infection (46%, p<0.05). Anti-HCV positive/anti-HBc positive patients, lacking both HBsAg and anti-HBs, compared with the anti-HCV positive/anti HBc negative ones, more frequently showed severe clinical presentation and less frequently had a sustained response to a-IFN treatment.     

Occult hepatitis B virus infection in the setting of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co‐infection: Clinically relevant or a diagnostic problem?

The clinical relevance of occult hepatitis B virus (HBV) infection, defined as detectable HBV DNA serum/liver, in the absence of hepatitis B surface antigen (HBsAg), is unclear. We determined the prevalence of serum occult HBV infection in HIV/HCV co-infected patients enrolled in APRICOT, a randomized multinational trial that investigated the efficacy and safety of peginterferon alfa-2a (40 kDa) plus ribavirin for treatment of HCV. We also examined the effect of prior HBV exposure to liver histology at baseline. Only HBsAg-negative patients were eligible. At screening, serum HBV DNA was assessed by commercial assay (detection limit = 200 copies/mL). Patients were divided into four serological groups: anti-HBs+/anti-HBc+; anti-HBs-/anti-HBc+; anti-HBs+/ anti-HBc-; anti-HBs-/anti-HBc-. Baseline liver biopsy grade and stage were compared among groups. Serum HBV DNA was undetectable in all patients, (n = 866). Results of anti-HBs and anti-HBc was available for 176 patients: 60 (34.1%) anti-HBs+/anti-HBc+; 60 (34.1%) anti-HBs-/anti-HBc+; 11 (6.3%) anti-HBs+/anti-HBc-; 45 (25.6%) anti-HBs-/anti-HBc-. There were no differences among the groups in the histological grade or stage at baseline liver biopsies. Occult HBV infection in serum was not detected in this large immunocompetent cohort. Moreover, prior exposure to HBV did not appear to have any affect on baseline liver histology.     

Seroprevalence of hepatitis B virus among health care workers in Korea

We studied the seroprevalence of HBsAg, anti-HBs and anti-HBc and the vaccination histories among health care workers (HCWs) at a large suburban referral hospital in Korea. The purpose of this study was to determine the immune status of HCWs against hepatitis B virus and we also wanted to prepare a practical guideline to protect HCWs from occupational exposure. During December, 2003, 571 HCWs (56 physicians, 289 nurses, 113 technicians and 113 aid-nurses) aged between 21 and 74 yr were included in the surveillance. The positive rates of HBsAg and anti-HBs were 2.4% (14/571) and 76.9% (439/571), respectively. The positive rate of anti-HBs was lower in the physician group, and this was associated with the male gender and older age. Of the 439 anti-HBs positive cases, 320 cases (73.1%) were anti-HBc negative and this was significantly associated with a past history of HBV vaccination. The distribution of the anti-HBs levels was not associated with age (except for HCWs in their sixties), gender or occupation. Our study revealed that the seroprevalence rates of HBsAg and anti-HBs in HCWs in Korea were not different from those of the general population. Based on this surveillance, we can make reasonable decisions in case of occupational exposure to hepatitis B virus.     

Antibodies to hepatitis B virus and hepatitis C virus in residential detoxification clients in Jamaica

The role of non-injecting drug abuse in viral hepatitis has not been studied widely and is not well understood. A total of 301 substance abusers, residents of a detoxification/rehabilitation unit, were investigated for exposure to hepatitis B virus (HBV) and hepatitis C virus (HCV). Samples of serum were tested for anti-HCV and anti-HBc antibodies and HBsAg. All of the patients were non-injecting drug users (non-IDUs). The prevalence of anti-HCV was 1.7%; anti-HBc was found in 28.7% and HbsAg in 0.6% of patients. Anti-HCV positivity correlated with the presence of elevated aminotransferases (80%). Exposure to HBV correlated significantly with gender (p < 0.05); age (p < 0.05); and duration of substance abuse (p < 0.05). No significant correlations were found between HCV and/or HBV infection, the drug of abuse, HIV, HTLV-1 or syphilitic infection. Residential detoxification/rehabilitation provides an opportune moment to identify and treat HCV positive substance abusers in the attempt to avert the severe hepatic sequelae. Measures which exclude substance abusers from volunteer blood donation should be considered.     

Seroepidemiological studies on hepatitis B and D viruses infection among five ethnic groups in southern Taiwan

In order to compare the prevalence of hepatitis B virus (HBV) and hepatitis D virus (HDV) infection among five ethnic groups in Pingtung County of southern Taiwan, a total of 240 serum samples were collected from September to October, 1985, from the following five ethnic groups: Taiwanese, Hakka, Mainland Chinese, aboriginal Paiwanese, and aboriginal Rukaiese. Ages of subjects ranged from 5 to 69 years. All sera were tested for hepatitis B surface antigen (HBsAg), surface antibody (anti-HBs), and core antibody (anti-HBc) by radioimmunoassay (RIA). Hepatitis B e antigen (HBeAg) and antibody to hepatitis D antigen (anti-HDV) were also tested for those with HBsAg-positive sera. Results showed that 44.1% of all sera examined were negative for HBsAG but positive for both anti-HBs and anti-HBc; additionally, 24.6% were negative for both HBsAg and anti-HBs but positive for anti-HBc. Only 134 serum samples showed negative results for HBV markers, indicating an HBV infection rate of 88.8%. The anti-HDV positive rate was estimated to be 2.7% among HBsAg-positive subjects. The HBsAg-positive rates among Rukaiese, Paiwanese, Hakka, Taiwanese, and Mainland Chinese were 25.8, 22.5, 16.7, 12.9, and 10.0%, respectively; while the prevalence rates of HBV infection among the above five groups were 94.2, 94.6, 85.4, 87.5, and 82.5%, respectively. Differences in the HBsAg-positive rate and HBV infection rate among these ethnic groups were statistically significant. We conclude that people living in Pingtung County are more frequently infected with HBV when compared with inhabitants in northern Taiwan.     

Changes in serologic markers of hepatitis B following autologous hematopoietic stem cell transplantation.

Korea is an endemic area for hepatitis B virus (HBV) infection. Reactivation of HBV is a well-recognized complication in patients with chronic HBV infection undergoing cytotoxic or immunosuppressive therapy, and there are some reports of hepatitis B reverse seroconversion after HSCT. This study evaluated changes in HBV serology after HSCT. We reviewed the medical records of 141 patients who had available HBV serologic data after autologous HSCT. Patient information was retrospectively collected from the BMT database. Before transplantation, 12 patients were positive for hepatitis B surface antigen (HBsAg) and received lamivudine prophylaxis. There was 1 case of reactivation of HBV among these patients. One hundred twenty-nine patients were negative for HBsAg before HSCT, of whom 110 were positive and 19 were negative for hepatitis B surface antibody (anti-HBs). Sixty-two of the 110 patients who were positive for anti-HBs were also positive for hepatitis B core antibody (anti-HBc). Eight patients were negative for anti-HBs and anti-HBc. Seven patients who were initially negative for HBsAg were identified as positive after HSCT, and 5 of those 7 patients developed acute hepatitis, thus indicating reverse seroconversion. Univariate analysis showed that reverse seroconversions were observed more frequently with multiple myeloma than another disease (P = .005; relative risk, 11.854; 95% confidence interval, 1.381-101.770). Other factors, such as age, sex, and presence of HBcAb before HSCT, had no statistically significant affect on reverse seroconversion. In conclusion, reverse seroconversion of HBV is not a rare complication of autologous HSCT, and the risk of reverse seroconversion after treatment is a serious concern due to possible complications arising from patients' suppressed immune systems.     

Occult hepatitis B virus infection in HBs antigen-negative hepatocellular carcinoma in a Japanese population: involvement of HBx and p53

Hepatitis B virus (HBV) genome was reported to be detected in serum or liver tissues in hepatocellular carcinoma (HCC) patients negative for hepatitis B surface antigen (HBsAg). Hepatitis B x (HBx) and p53 protein were reported to play an important role in HBV-related hepatocarcinogenesis. To clarify latent HBV infection in HBsAg- and anti-hepatitis C virus (anti-HCV)-negative HCC in a Japanese population and involvement of HBx and p53 protein in these patients, we performed the sensitive and specific nested polymerase chain reaction (PCR) and immunohistochemical analysis. Of 1,024 HCC patients we saw between 1974 and 1998, 66 (6.4%) were negative for HBsAg and anti-HCV. Serum DNA was amplified by nested PCR by using specific primers of surface (S), core (C) and X regions in 26 patients negative for HBsAg and anti-HCV. Eighteen (69%) patients were positive for either S, C, or X region and the results of PCR were confirmed by Southern blotting. Of 18 PCR-positive patients, 3 were positive for anti-HBs and 9 were positive for anti-HBc, however, one was negative for any HBV markers. In HBsAg-negative and PCR-positive patients, the positive rates of expression of HBx and p53 were 8/13 (62%) and 7/13 (54%), being comparable to those in HBsAg-positive HCC patients. The results of the present study suggest that high prevalence of HBV infection is observed in HBsAg-negative HCC in a Japanese population and expression of HBx and p53 is consistent with a role, in these patients, for the transforming ability of these proteins.     

Seroprevalence of hepatitis C virus in haemophiliacs in Jamaica

Haemophilic patients (n = 90) and household contacts (n = 40) were tested for serological markers of hepatitis B virus (HBV), hepatitis C virus (HCV) and elevated serum aminotransferases using commercially prepared reagents. Of the haemophiliacs 41% (37/90) tested positive for antibodies to HCV (anti-HCV); 36% (32/90) antibodies to hepatitis B core antigen (anti-HBc); 54% (49/90) antibodies to hepatitis B surface antigen (anti-HBs) and 2% (2/90) hepatitis B surface antigen. On the other hand, 29% (26/90) of the patients and 90% (36/40) of the household contacts tested negative for all of the viral markers. Anti-HCV positivity in the haemophilic patients correlated positively with anti-HBc (p < 0.025). Increasing age (odds ratio 2.09; p < 0.01), severity of disease (odds ratio 6.2; p < 0.05) and the requirement for transfusion (odds ratio 3.2; p < 0.05) were risk factors for anti-HCV positivity. The presence of anti-HBc (odds ratio 3.8; p < 0.01) and coinfection with HCV and HBV also correlated positively with age (odds ratio 2.5; p < 0.01). The provision of anti-HCV screened donor blood and virally inactivated blood products for treatment of all haemophilic patients are goals that must be achieved.     

The value of screening blood donors for antibody to hepatitis B core antigen.

Rapid counter-immunoelectrophoresis (CIE) and radioimmunoassay (RIA) methods for detecting antibody to hepatitis B core antigen (anti-HBc) were used to screen nearly 8000 blood donors, including 919 prisoners. The prevalence of anti-HBc in prisoner donors (3.4%) was significantly higher than that in other donors (0.7%). The three HBsAg positive donors in the series were all anti-HBc positive and, of the other 73 anti-HBc positive donors, 62 had antibody to HBsAg (anti-HBs). Two panels of control sera, including 155 HBsAg positive samples, were tested by CIE for anti-HBc: 149 of the 155 were anti-HBc positive. Of the six negative samples, four were HBsAg positive only by RIA. One of the panels, containing 16 weakly HBsAg positive samples, was available for anti-HBc testing by RIA. Fifteen of the samples were positive and the other was slightly reactive. Donor sera that gave unconfirmable reactions in initial CIE tests were invariably negative when tested by RIA. The RIA was a more sensitive and specific test for anti-HBc than CIE. The ways in which anti-HBc screening could meet the needs of blood transfusion centres are discussed. We suggest that, in areas of low prevalence, it has a role as a rapid confirmatory test of HBV infection and as a means of identifying those potentially infectious donations in which HBsAg cannot be detected.     

Seroprevalence of Hepatitis-B infection amongst Taiwanese university students 18 years following the commencement of a national Hepatitis-B vaccination program

In Taiwan, the nation-wide Hepatitis-B virus (HB) vaccination program was first launched in July 1984 and was directed to those infants born to hepatitis B surface antigen (HBsAg) carrier mothers in Taiwan. From July 1986 onwards, all infants born in Taiwan were immunized against HB. This study examined the HB-infection status amongst students at a Taiwanese university 18 years subsequent to the implementation of universal HB vaccination. A total of 1,969 new university entrants in 2005 were grouped into 1 of 3 distinct birth cohorts according to their HB-vaccination schedule (cohort-1 students born prior to July 1, 1984; cohort-3 students born subsequent to June 30, 1986) and were examined for their serum HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) status. Immunity arising from vaccination was defined as an anti-HBs level 10 mIU/ml. We observed a trend toward a decreasing anti-HBc-positive rate and a decreasing HBsAg carrier rate from, respectively, 26.5 and 8.7% for cohort-1 to 4.7 and 1.7% for cohort-3 students. The prevalence of students featuring seronegativity for all three HB markers increased from 12.3% for cohort-1 to 48.8% for cohort-3 individuals. Amongst the 1,695 subjects revealing seronegativity for HBsAg and anti-HBc, their anti-HBs level was analyzed according to their birth year. The prevalence of students featuring a non-protective anti-HBs level increased from 11.9% for birth-year 1984 individuals to 48.2% for birth-year 1987 students. The introduction of HB vaccine has effectively reduced the transmission of HBV infection in Taiwan, 18 years subsequent to the commencement of the universal HB-vaccination program. A "waning-off" effect of anti-HBs seropositivity acquired from the HB vaccination program has also been observed.