Low-dose vaccination against hepatitis B in children: one-year follow-up

Six hundred forty-three children, negative for markers of hepatitis B virus (HBV) infections, were given three X 2-micrograms doses of Merck, Sharp and Dohme (MSD) plasma derived hepatitis B vaccine (H-B-Vax) at monthly intervals. Twelve months after the first dose of vaccine, antibody to hepatitis B surface antigen (anti-HBs) was detected in 89% of children by radioimmunoassay (RIA) and in 83% by enzyme immunoassay (EIA). Seroconversion rates and anti-HBs titres were significantly greater in 1-4-year-olds than in older children (p less than 0.01). Eighteen children with no anti-HBs or other markers of HBV at this time were given 10 micrograms of vaccine and tested one month later. Seventeen developed anti-HBs, 12 at levels consistent with an anamnestic response. Forty-nine HBV-marker-negative children seroconverted for antibody to hepatitis B core antigen (anti-HBc) in the 8-month period before or the 12-month period following vaccination. Forty-six of these children were positive for anti-HBs, and one has been confirmed as a chronic carrier of hepatitis B surface antigen (HBsAg). Three cases of clinical hepatitis B in children have been seen in the community since the vaccination programme began. Two of these were amongst the estimated 5% of children who were not vaccinated. The third was in a vaccinee and occurred 4 1/2 months after the last dose of vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

The isolated presence of anti-HBc antibodies: prevalence and interpretation based on the results of viral DNA research and anti-HBs antibodies measurement after vaccination

In order to study the significance of the isolated presence of anti-HBc antibodies, we have looked for the 3 classic serological markers of the hepatitis B (HBs antigen, anti-HBs and anti-HBc antibodies) in 1,586 hospital agents who are to vaccinate in the framework of a campaign of systematic vaccination of the hospital personnel of university hospitals of Sfax for a period of 18 months. We identified subjects who presented isolated anti-HBc antibodies (33 individuals = 2.08%). In these subjects'serum, we performed a research of the DNA of hepatitis B virus (HBV) with a PCR hybridization technique using a couple of primers. One week after administration of a vaccine dose, we also measured anti-HBs antibodies in their sera. Among the tested 18 personnel with anti-HBc isolated antibodies, 11.1% had low rates of anti-HBs antibodies indicating that there is presumably primary antibody response and therefore a false positivity of anti-HBc antibodies in pre-vaccinal serology; while 11.1% others had higher rates of anti-HBs antibodies corresponding to a secondary antibody response, which witness a previous HBV immunisation. The research of the HBV-DNA was positive in 11.1% of tested personnel, testifying a presumably chronic portage of the virus with low rates of the HBs antigen undetectable with the serological techniques. For the remainder subjects with isolated anti-HBc antibodies (66.7%), the interpretation remains ambiguous.     

Immunoregulation of the in vitro anti-HBs antibody synthesis in chronic HBsAg carriers and in recently boosted anti-hepatitis B vaccine recipients.

We report a study on immunoregulation of in vitro antibody to hepatitis B surface antigen (anti-HBs) synthesis induced by pokeweed mitogen (PWM) from peripheral blood mononuclear cells (PBMC) in chronic hepatitis B surface antigen (HBsAg) carriers and in 'high responders', (anti-HBs RIA ratio greater than or equal to 20 in serum), recently boosted with anti-hepatitis B vaccine. Anti-HBs was detected in 11 days PBMC supernatants (SN) from 24 out of 36 'high responders', but in none from 31 chronic HBsAg carriers, despite detectable amounts of polyclonal IgG and antibody to hepatitis B core antigen (anti-HBc) were produced. The lack of anti-HBs production by chronic HBsAg carriers did not seem to be determined by suppressor influences because T lymphocytes from the majority of chronic HBsAg carriers, co-cultured with 'high responders' PBMC did not suppress anti-HBs production. Co-cultures between HBsAg carriers T4 positive (helper/inducer) cells and allogenic 'high responder' non-T cells produced anti-HBs antibody, indicating that HBsAg carrier T cells are not deficient in this allogenic helper function under PWM stimulation. Allogenic cocultures between HBsAg carrier non-T cells and 'high responder' T4 positive cells failed in anti-HBs production: a specific B lymphocyte defect might be involved in the lacking anti-HBs synthesis in chronic HBV patients. Antigen-induced specific anti-HBs synthesis experiments indicate that B cells themselves seem to be the target for HBsAg-induced suppression of anti-HBs antibody response.     

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.     

HBV and HCV infection in Japanese dental care workers

Protective measures against occupational exposure to the hepatitis B virus (HBV) and hepatitis C virus (HCV) must be taken in order to prevent infection in dental care workers. To determine the best way to protect these workers, our study examined viral hepatitis infection in dental care workers in regions with a high prevalence of HCV infections in Japan. In total, 141 dental care workers (including dentists, dental hygienists and dental assistants) were enrolled. After a questionnaire to elicit demographic information was administered by an oral surgeon, hepatitis B surface antigen (HBsAg), antibody to HBs (anti-HBs), antibody to hepatitis B core antigen (anti-HBc) and antibody to HCV (anti-HCV) were measured. When necessary, HBeAg, anti-HBe, levels of HBV DNA, anti-HBc IgM and HCV RNA in serum were measured. Of the dental care workers included, 68 (48.2%) had been immunized with a HBV vaccine. Only 9 wore a new pair of gloves for each new patient being treated, 36 changed to a new pair only after the old gloves were torn and 24 did not wear any gloves at all. No one was positive for HBsAg or anti-HCV, though 73 (51.8%) and 17 (12.1%) workers were respectively positive for anti-HBs and anti-HBc. The positive rate of anti-HBc varied directly with worker age and experience. Of the 68 workers immunized with HBV vaccine, 51 (75%) were positive for anti-HBs. Of the 63 workers who were not so immunized, 17 (27%) were positive for anti-HBs and 15 of these were also positive for anti-HBc. Immunized workers were more protected against HBV infection than non-immunized workers, indicating that HBV vaccine was a useful measure for protection against the infection. The anti-HBc positive rate was significantly higher among dental care workers than general blood donors, suggesting that frequency of exposure to HBV was greater in dental care workers. HBV vaccination should be made compulsory for all dental care workers who handle sharp instruments.     

Epidemiology of hepatitis B in eastern Kenya

A cross-sectional survey of outpatients attending the three distinct hospitals in the towns of Mombasa, Kilifi, and Malindi was conducted to determine the patterns of hepatitis B transmission in eastern Kenya. Of 1,533 study subjects (mean age 21.9 +/- 13.2 years; range, 4 months to 80 years), 11.4% were positive for HBsAg and 56.2% were seropositive for at least one hepatitis B marker (HBsAg, anti-HBs, or anti-HBc). Anti-delta antibody was found in 1.2% of HBsAg-positive samples. HBeAg was found in 36.0% of HBsAg-positive samples obtained from women of childbearing age. The prevalence of seropositivity for hepatitis B markers was positively correlated with age, increasing from 20% in subjects less than 4 years old to more than 80% in study subjects greater than 40 years old. On multivariate analysis, male sex was found to be associated with HBsAg positivity, and age and previous deliveries of children were associated with seropositivity for any hepatitis marker (HBsAg, anti-HBs, or anti-HBc). An effective hepatitis B immunization strategy in this region of Kenya would require vaccination early in life because a major portion of hepatitis B transmission occurs in childhood.     

The immune response of healthy Nigerian adults to small doses of hepatitis B vaccine: comparison of 10- and 20-micrograms doses

The immunogenic effect of hepatitis B vaccine (H-B-vax) was evaluated in 120 seronegative healthy Nigerians. Three doses of the vaccine were given at 0, 1, and 6 months. Serial blood samples were tested 1 month after each vaccination for hepatitis B surface antibody (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc). Of 60 vaccines given 20 micrograms of the vaccine, 40% had significant anti-HBs response 1 month after the first dose, 70% after the second dose, and 91.7% after the third dose. In the 60 vaccines given 10-micrograms doses, the seroconversion rates were 35, 73.3, and 90%, respectively. It is concluded that this vaccine in 10-micrograms doses is as effective as the larger doses in producing anti-HBs. The administration of small doses would reduce the cost of large-scale vaccination programs in developing countries.     

Seroepidemiology of hepatitis A, B, and D viruses and human T-lymphocyte tropic viruses in Japanese drug abusers

To evaluate the prevalence of hepatitis virus markers and human T-cell lymphotropic virus infections among drug abusers in Japan, serum samples were collected from 91 male drug abusers at the Shinshu University Hospital and the rehabilitation facility in Matsumoto and from 519 healthy male blood donors as controls. Sera were tested for antibody to hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to hepatitis B core antigen (anti-HBc), immunoglobulin M anti-HBc (IgM anti-HBc), antibody to hepatitis D virus (anti-HDV), antibody to HTLV type 1 (anti-HTLV 1), and antibody to human immunodeficiency virus (anti-HIV). The prevalence of anti-HAV was 13.2% in drug abusers and 10.8% in controls (not significant). The prevalences of HBsAg, anti-HBs, anti-HBc and exposure rate to hepatitis B virus (HBV) were 4.4%, 24.2%, 31.9%, and 35.2%, respectively, in drug abusers and 0.8%, 6.7%, 9.6%, and 9.6% in controls. The exposure rate to HBV was significantly different (P less than 0.001). IgM anti-HBc and anti-HDV were not detected in any sera. Anti-HTLV I was detected in three drug abusers (3.3%) and in one (0.2%) of the controls (P less than 0.01). All sera were negative for anti-HIV in all subjects. Infection with HBV and HTLV I is more common among drug abusers than in the general population of blood donors in Japan.     

Comparison of two techniques for detecting antibody to HBsAg during a hepatitis B vaccine study

Two assays for the detection of antibody against hepatitis B surface antigen (anti-HBs) were compared. The first was a direct sandwich radioimmunoassay (RIA) which detects, in principle, antibody against any epitope of hepatitis B surface antigen (HBsAg). The second assay was an inhibition enzyme-linked immunosorbent assay (ELISA). In this assay a fixed amount of HBsAg which can be blocked by anti-HBs is measured in a direct sandwich test. Prevaccination screening sera (n = 191) and follow-up sera obtained from high risk groups (n₁ = 85; n₂ = 41) during two hepatitis B vaccine studies were compared in RIA and ELISA. In prevaccination sera either HBsAg or anti-HBs were detected by ELISA. Full agreement between the results of RIA and ELISA for anti-HBs was obtained in sera containing more than 10 IU/1 anti-HBs. Both tests showed variable results at low titres. Experiments with monoclonal anti-HBs indicated that ELISA is less sensitive for subtype specific antibodies (anti-d, anti-y), which may explain that there were consistent differences between RIA and ELISA in a minority of cases.     

Long-term anti-HBs antibody persistence and immune memory in children and adolescents who received routine childhood hepatitis B vaccination

This paper presents data from two studies that evaluated 5-y and 10-y persistence of antibodies against hepatitis B (HBV) surface antigen (anti-HBs) and immune response to an HBV vaccine challenge in children and adolescents who had received three doses of a HBV vaccine in infancy as part of routine clinical practice [NCT00519649/NCT00984139]. Anti-HBs antibody concentrations ≥ 10 mIU/ml persisted in 83.3% (95% confidence interval [CI]: 78.5–87.5) and 78.3% (95% CI: 73.1–83.0) of subjects aged 7–8 y and 12–13 y, respectively 5–10 y after infant vaccination. One month postchallenge dose, 98.2% (95% CI: 95.9–99.4) and 93.7% (95% CI: 90.2–96.2) of subjects in the two age groups, respectively had anti-HBs antibody concentrations ≥ 100 mIU/ml. Overall, 99.6% (95% CI: 98–100) and 97.2% (95% CI: 94.5–98.8) of subjects aged 7–8 y and 12–13 y mounted an anamnestic response to the HBV challenge dose, which was well-tolerated. Healthy children aged 7–8 y and adolescents aged 12–13 y received three doses of a monovalent pediatric HBV vaccine (10 μg of HBsAg) before 18 mo of age. Serum samples collected before and one month post-HBV vaccine challenge dose were tested for anti-HBs antibody concentrations. Safety assessments were made for the HBV vaccine challenge dose. A three-dose childhood HBV immunization regimen induced persistence of antibodies against HBV infection for 10 y, up to adolescence. This vaccination regimen also conferred long-term immune memory against HBV as evidenced by the strong anamnestic response to the HBV vaccine challenge, despite waning anti-HBs antibody levels.     

Efficacy of hepatitis B virus (HBV) vaccine in long term prevention of HBV infection

Efficacy of HBV vaccine in long term prevention of HBV infection was evaluated at 3 years after vaccination in 38 children and 61 adults. All vaccinees were negative for all HBV markers (HBsAg, anti-HBs and anti-HBc) before vaccination. Vaccines (Hevac B) were given for 3 doses, one month apart, to 38 children aged 1 month - 14 years and 61 adults aged 15-45 years. After 3 years of vaccination, blood specimens were collected for the determination of HBsAg, anti-HBs and anti-HBc. The results revealed that no HBsAg antigenemia was found in all 99 vaccinees. Anti-HBs could not be detected in 4 children and 11 adults and this occurred only in the group of subjects who had initial anti-HBs less than 100 mlU/ml at 2 months after the last dose of vaccination. At three years after the first course of vaccination, 89.4 percent of children and 83.4 percent of adults still have anti-HBs above protective level (more than 10 mlU/ml) with geometric mean titers of 101 and 35 mlU/ml in children and in adult groups, respectively. The anti-HBc was detected in 2 out of 38 children and 10 out of 61 adults, but none of them became chronic hepatitis B carriers or developed clinical disease. It is recommended that everyone with anti-HBs values below 100 mlU/ml two months after the last dose of vaccine should be revaccinated with a booster dose within 6 months. Those with anti-HBs levels higher than 100 mlU/ml, should be checked up at 3 years; if the anti-HBs is less than 10 mlU/ml, they should be revaccinated.     

Seroprevalence and risk factors for hepatitis B infection in an adult population in Northeast China

Background and aim: The prevalence of the hepatitis B virus (HBV) is higher in adults than in children. We determined the seroepidemiology of HBV infection in an adult population in JiLin, China, to guide effective preventive measures.Methods: A cross-sectional serosurvey was conducted throughout JiLin, China. A total of 3833 people was selected and demographic and behavioral information gathered. Serum samples were tested for HBV markers and liver enzymes.Results: The prevalence of the hepatitis B surface antigen (HBsAg), the antibody to the hepatitis B surface antigen (anti-HBs), the hepatitis B e antigen (HBeAg), the antibody to HBeAg (anti-HBe), and the antibody to the hepatitis B core antigen (anti-HBc) were 4.38%, 35.66%, 1.38%, 6.65%, and 40.88%, respectively. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were significantly higher among HBsAg (+) than HBsAg (-) subjects. By multivariate logistic regression analysis, independent predictors for chronic HBV infection were smoking, poor sleep quality; occupation as private small-businessmen, laborers, or peasants; male gender; family history of HBV; personal history of vaccination; and older age. Independent predictors for exposure to HBV were large family size, occupation as a private small-businessman, male gender, family history of HBV, personal history of vaccination, and older age. Independent predictors for immunity by vaccination were occupation as a private small-businessman, high income, personal history of vaccination, and young age. Independent predictors for immunity by exposure were drinking, male gender, personal history of vaccination, and older age.Conclusions: The prevalence rate of HBV infection (4.38%) was lower than the previous rate of general HBV vaccination. However, 44.59% of the population remained susceptible to HBV. The prevalence of HBV infection was high in young adults, private small-businessmen, peasants, those with a family history of HBV, and males. Therefore, immunization of the non-immune population is reasonable to reduce hepatitis B transmission between adults.     

Hepatitis B virus (HBV) infections in turtles

Thirty turtles (15 Clemys mutica and 15 Geoclemys reevesii) which were inoculated with human sera those were positive for hepatitis B surface antigen (HBsAg) and hepatitis B "e" antigen (HBeAg) were found to be infected with hepatitis B virus (HBV). The levels of HBV infection markers, such as HBsAg and antibody to HBsAg (anti-HBsAg), were retinely monitored in the turtles' serum for 46 weeks. Within two weeks of the inoculation, 42% of the turtles tested were positive for HBsAg, and their reciprocal titers as measured by reverse passive hemagglutination (RPHA) and enzyme linked immunoabsorbance assay (ELISA) ranged from 16 to 96. Within 20 weeks, the remaining turtles tested HBsAg positive, as confirmed by ELISA. At 20 weeks, all but one of the turtles exhibited changes in HBV blood marker from HBsAg to anti-HBs; the one exception was positive for both HBsAg and anti-HBs. At the 47th week, 7 animals were killed and their organs were examined for HBV infected cells utilizing an immunofluorescent technique. Numerous fluorescent cells which reacted with human anti-HBs nad anti-HBc were observed in the following organs: pancreas, liver, kidney, and brain. Histopathologically, edematous changes in hepatocytes and minor cellular infiltration attributed to an inflammatory response were noted. Liver and kidney cells from the infected animals were cultured, and HBV antigen positive cells for HBsAg and HBcAg were detected in the cultures. Throughout the experiment, HBsAg was detected in the supernatant by ELISA. Virus particles which were indistinguishable from Dane particles were seen in the cytoplasmic vacuoles of the cultured cells by electron microscopy. Finally, the presence of HBV DNA was established by molecular hybridization techniques in the culture supernatants of kidney cells from the infected turtles.     

Seroepidemiology of hepatitis B virus, hepatitis D virus, and human immunodeficiency virus infections among parenteral drug abusers in southern Taiwan

A total of 390 parenteral drug abusers (PDAs) at the Kaohsiung Municipal Narcotics Abstention Institute were examined for markers of hepatitis B virus (HBV), hepatitis D virus (HDV), and human immunodeficiency virus (HIV). All sera were tested for hepatitis B surface antigen (HBsAg), surface antibody (anti-HBs), and core antibody (anti-HBc) by radioimmunoassay (RIA) and for antibody to HIV (anti-HIV) by enzyme-linked immunosorbent assay (ELISA). Hepatitis B e antigen (HBeAg) and antibody to HDV (anti-HDV) were also tested for HBsAg-positive serum samples. Although the HBsAg-positive rate (22.1%) among PDAs was similar to that of the general population in southern Taiwan, the HBV infection rate (99.2%) and the anti-HDV-positive rate (78.5%) among HBsAg-positive subjects were significantly higher than those of the general population in southern Taiwan (P less than 0.0001). None of the PDAs studied were positive for anti-HIV. The levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) among PDAs were significantly higher than those of the general population in southern Taiwan (P less than 0.0001). The more frequent the institutionalisation, the higher the infection rates with HBV and HDV and elevated levels of SGOT and SGPT. Horizontal transmission through parenteral drug abuse may be considered a possible reason for the significantly higher rates of HBV and HDV among parenteral drug abusers.     

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.     

Significance of blood-related high-risk behaviors and horizontal transmission of hepatitis B Virus in Iran

Hepatitis B virus (HBV) is a significant public health problem and a leading cause of morbidity and mortality, and approximately 30% of the world's population is infected with HBV. The objective of our study was to determine the seroprevalence of HBV and major risk factors associated with its occurrence. Four thousand eighty-seven healthy Iranian subjects aged 8-80?years were screened for HBV serological markers by an enzyme immunoassay method. A structured questionnaire was administered to all participants. Multiple logistic regression, an unpaired t-test for continuous data and the χ (2) test for categorical data were performed. A total of 4087 participants were tested for hepatitis B surface antigen (HBsAg), of which 62 (1.5%) were seropositive. Fifteen percent of the subjects were positive for anti-HBs, 6.3% were positive for isolated anti-HBc and 12.5% were positive for both anti-HBs and anti-HBc. Laborers showed a higher HBsAg(+) seroprevalence and risk compared with jobless participants (Pearson's?=?8.276, P?=?0.004; OR?=?4.1, 95% CI: 1.5-11.2). Bivariate logistic regression revealed that the following variables were significantly associated with HBV seropositivity: phlebotomy (P?=?0.002; OR?=?5.0, 95% CI: 2.1-11.9), tattooing (P?=?0.003; OR?=?3.4, 95% CI: 1.6-7.0), intravenous drug use (P?=?0.001; OR?=?2.4, 95% CI: 1.4-4.1). The adjusted prevalence ratios remained significantly associated with HBV seropositivity and thus likely served as possible risk factors for HBV. The overall positive seroprevalence was 1.5%. Among the variables, only phlebotomy, tattooing and intravenous drug injection emerged as major potential risk factors for hepatitis B infection and responsible for transmission of the disease.     

Significance of isolated hepatitis B core antibodies detected by enzyme immunoassay in a high risk population.

Serum samples, which were found positive for anti-HBc and negative for HBsAg and anti-HBs during routine testing with Abbott enzyme immunoassays (EIA), were collected prospectively. The samples were obtained from patients with a high risk of hepatitis B. Further analysis was carried out using radioimmunoassays and tests for additional markers of hepatitis B. 84 of the 203 initially collected samples (41.4%) were found positive for anti-HBs by RIA. Of the 119 samples negative for anti-HBs by RIA, 103 were available for further investigation, and 35 (34.0%) of these were negative for anti-HBc by RIA. This indicates that low sensitivity of the anti-HBs EIA and non-specificity of the anti-HBc EIA may account for about 60% of the cases presenting with isolated anti-HBc at initial testing. Fifty-two samples positive for anti-HBc by RIA, with isolated anti-HBc confirmed after RIA testing for HBsAg and anti-HBs, were examined further: anti-HBe was detected in 16 sera, anti-HDV in one serum and HBV-DNA in 5 sera by PCR. Additional testing of serum samples with isolated anti-HBc is warranted.     

Serum hepatitis B virus DNA in healthy HBsAg-negative Chinese adults evaluated by polymerase chain reaction

Serum hepatitis B virus (HBV) DNA was assayed using polymerase chain reaction, in 107 HBsAg-negative normal Chinese subjects. The results showed that eight subjects (7.5%) had HBV DNA. In the subgroup with antibody to hepatitis B surface antigen (anti-HBs) and to hepatitis B core antigen (anti-HBc), 7.3% (5/68) were positive for HBV DNA; HBV DNA was not detected in six individuals with anti-HBs only and in nine with anti-HBc only. In four persons with anti-HBc and anti-HBe, one had HBV DNA. In 20 subjects negative for all hepatitis B serological markers, two (10%) were found to have HBV DNA. This study indicates that serological markers are not adequate to rule out HBV infection, and it further implies that present blood donor screening methods may need improving.     

Detection and significance of anti-HBc in the blood bank; preliminary results of a controlled prospective study

It has been suggested that post-transfusion hepatitis B (PTHB) may occur after transfusion with blood negative for hepatitis B surface antigen (HBsAg) but positive for antibody against hepatitis B core antigen (anti-HBc). We are currently conducting a controlled prospective study of recipients of such blood to investigate this possibility.Blood donors were routinely screened for HBsAg by radioimmunoassay (RIA) and those found negative were tested for anti-HBc by RIA. The HBsAg negative, anti-HBc positive donors were then tested for antibody directed against HBsAg by RIA, antibody directed against hepatitis B ‘e’ antigen by enzyme-immunoassay and for the liver enzymes SGOT and SGPT.Todate, follow-up has been completed in the recipients of 141 anti-HBc positive blood donors and in a control group of the recipients of 141 anti-HBc negative blood donors. All the recipients were bled repeatedly with intervals of 4–5 weeks up to 7 months post-transfusion. Currently, no clear-cut sero con version was observed in recipients of either group for any of the antibody markers of HBV infection. While none of the 141 recipients of anti-HBc negative blood became positive for HBsAg, recipients of anti-HBc positive blood acquired HBsAg and developed clinically manifest post-transfusion hepatitis B.