Isolated hepatitis B core antibody--can response to hepatitis B vaccine help elucidate the cause?

Isolated Anti-HBc: Significance and Management

Hepatitis B virus (HBV) infection is prevalent worldwide and is associated with dramatic levels of morbidity and mortality. Isolated anti-HBc (IAHBc) is a particular serological pattern that is commonly found in immunocompromised patients. There is ongoing debate regarding the management of patients with IAHBc. Herein, we summarize the current guidelines and the newest evidence. The frequency of IAHBc is variable, with a higher prevalence in some populations, such as persons living with HIV and others immunocompromised patients. The risk of HBV reactivation depends on host factors (including immunosuppression) and viral factors. It is now well established that immunocompromised patients can be classified into three groups for risk according to the type of immunosuppression and/or treatment. In patients at high risk, HBV therapy has to be considered systematically. In patients at moderate risk, the decision is based on the level of HBV DNA (preemptive treatment or monitoring and vaccination). In patients with low risk, HBV vaccination is another possible approach, although further studies are needed to assess the type of preemptive strategy.

Effectiveness of a hepatitis B vaccination program at two tertiary hemodialysis centers

INTRODUCTION

Hemodialysis (HD) patients are at increased risk of hepatitis B infection in comparison to the general population. Despite a more intensified hepatitis vaccination regimen, response rates in HD patients are typically low. The study was conducted to quantify response rate to a new hepatitis B vaccination protocol initiated in late 2015, determine risk factors affecting response rate, and assess adherence to protocol.

METHODS

This retrospective chart review evaluated all HD patients eligible for hepatitis B vaccination in two large dialysis clinics from initiation of the hepatitis B protocol to July 2017. Recombinant hepatitis vaccine (Recombivax® HB) 40 μg was administered in a 3-dose regimen at months 0, 1, and 6 to patients with hepatitis B surface antibodies (anti-HBs) <10 mIU/mL. A repeat series was given if anti-HBs levels remained below 10 mIU/mL after the first series. A booster dose was given if anti-HBs titers fell below 10 mIU/mL after initial response to a second series vaccination.

FINDINGS

Of 411 patients at the two HD centers, 142 patients received hepatitis B vaccination with a total of 168 vaccine courses given, series 1: n = 86, series 2: n = 60 and booster: n = 22. Response rates to vaccination were 61.4%, 58.3%, and 81.8%, respectively. In univariate analysis, adherence to protocol significantly affected response rate (P = 0.035). A multivariate analysis assessing response rates to series 1, 2 or booster confirmed that adherence was a significant risk factor (OR = 2.2; 95% CI 1.4-3.4; P = 0.0005).

DISCUSSION

This was the first study to examine adherence to regimen and identified adherence as an important predictor of vaccine response. Adherence is one of the few modifiable risk factors that can be optimized in an effort to improve response to hepatitis B vaccination.

Predictors of the isolated hepatitis B core antibody pattern in HIV-infected and -uninfected men in the multicenter AIDS cohort study

BACKGROUND

The significance of hepatitis B core antibody (anti-HBc) without hepatitis B surface antigen (HBsAg) or hepatitis B surface antibody (anti-HBs) is unclear.

METHODS

This cohort study included men enrolled in the Multicenter AIDS Cohort to determine clinical and laboratory predictors of isolated anti-HBc.

RESULTS

A total of 2286 subjects (51% human immunodeficiency virus [HIV]-infected) were followed over 3.9 years. Overall, 16.9% (387) had at least 1 visit with isolated anti-HBc. The isolated anti-HBc pattern was stable 84% of the time, and transitioned to or from a pattern of past infection (anti-HBc and anti-HBs). Isolated anti-HBc was associated with HIV infection (odds ratio [OR], 2.19; 95% confidence interval [CI], 1.73-2.79) and hepatitis C virus (HCV; OR, 4.21; 95% CI; 2.99-5.91). The HCV association was stronger for chronic HCV infection (OR, 6.76; 95% CI, 5.08-8.99) than for cleared HCV (OR, 3.03; 95% CI, 1.83-5.03). HIV infection, chronic HCV, and cleared HCV infection all remained associated with isolated anti-HBc in multivariable models (OR, 1.74; 95% CI, 1.33-2.29; OR, 6.24; 95% CI, 4.62-8.42; and OR, 2.77; 95% CI, 1.65-4.66, respectively). Among HIV-infected subjects, highly active antiretroviral therapy was negatively associated (OR, 0.79; 95% CI, .66-.95) with isolated anti-HBc.

CONCLUSIONS

Isolated anti-HBc is associated with HIV and HCV coinfection, especially active HCV replication, and most commonly occurs as a transition to or from the pattern of natural immunity (anti-HBc and anti-HBs). The isolated anti-HBc pattern likely represents resolved HBV infection with low or undetected anti-HBs.

Significance of isolated antibody to hepatitis B core antigen in Dutch national vaccination campaign of behavioural high-risk groups

In the Dutch national vaccination campaign for behavioural risk groups, anti-HBcore is used as the primary HBV screening test. Samples with positive results undergo testing for active infection (HBsAg) but are otherwise accepted as indicating past infection, thereby assuming immunity. This study evaluated evidence for immunity in the target population screened on the basis of this algorithm, by re-analysing 1000 anti-HBcore-positive blood samples equally divided among risk groups: 14·7% of confirmed anti-HBcore lacked anti-HBs (‘isolated’ anti-HBcore). Independent risk factors for isolated anti-HBcore were risk group, HCV infection in hard-drug users (DU) and origin from Sub-Saharan Africa. After extrapolation, the proportion of participants who were said to be immune but lacked any additional evidence of immunity amounted to 9·6% (ranging from 12·5% in DU to 6·5% in men who have sex with men). It is recommended that as a minimum anti-HBs screening is included in testing algorithms used to determine vaccination programmes for risk groups, in particular in DU.

Comparative long term immunogenicity of two recombinant hepatitis B vaccines and the effect of a booster dose given after five years in a low endemicity country

BACKGROUND

Few data are available concerning the long term immunogenicity of the pediatric doses of hepatitis B vaccines given to preteenagers. The long term effect of the booster dose in teenagers is unknown. We evaluated the immunogenicity of 2 pediatric hepatitis vaccines after primary vaccination and after a booster dose.

METHODS

A prospective 15-year follow-up study of the immunogenicity of 2 hepatitis B vaccines was initiated in 1995 in Quebec City, Canada. One year apart, 1129 children 8-10 years old received Engerix-B 10 microg (EB), and 1126 received Recombivax-HB 2.5 microg (RB) vaccine after a 0-, 1-, 6-month schedule. After 5 years, one-third of the 2 cohorts were randomly selected. A booster dose of EB 10 microg or RB 5 microg was administered according to the vaccine used in the primary immunization. Antibodies were measured before, 1 month after and 1 year after the booster injection.

RESULTS

Before the booster dose, anti-HB surface antibody (HBs) was detected in 94.7% of the EB subjects and in 95.2% of the RB subjects (P = 0.85). The geometric mean titer (GMT) was higher in the EB than in the RB group (252 mIU/mL versus 66 mIU/mL, P < 0.0001). One month after the booster, 99.7% of subjects in the EB group and 99.6% in the RB group had a detectable anti-HBs, and 99.0 and 99.3%, respectively, had anti-HBs > or =10 mIU/mL. The anti-HBs GMT was 113,201 mIU/mL in the EB and 16,623 mIU/mL in the RB groups (P < 0.0001). One year after the booster, 99.3% of subjects in the EB group and 100% in the RB group had detectable anti-HBs, and 97.9 and 98.5% respectively, had anti-HBs > or =10 mIU/mL. The anti-HBs GMT was 14,028 mIU/mL in the EB and 3437 mIU/mL in the RB group (P < 0.0001).

CONCLUSIONS

The immunity persists for at least 5 years after the primary vaccination with both pediatric vaccines in 99% of children vaccinated at the age of 8-10 years. It confirms that no booster is needed at that point.

The response of isolated anti-HBc positive subjects to recombinant hepatitis B vaccine

OBJECTIVE

The aim of this study was to evaluate the response to hepatitis B vaccination in isolated anti-HBc positive subjects.

PATIENTS AND METHODS

Forty-eight subjects with persistent isolated core antibody were included in the study. Fifty healthy people who were negative for HBsAg, anti-HBs and anti-HBc were included in the study as a control group. They all were vaccinated with recombinant hepatitis B vaccine at 0, 1 and 2 months.

RESULTS

Thirty days after each dose of vaccination, serum levels over 10IU/l of anti-HBs are found in 50% of the subjects with isolated anti-HBc after first; in 68.7% after second and in 89.6% after third vaccination. There were no statistical differences between the two groups (P > 0.05). Twenty subjects in isolated anti-HBc group (41.6%) but none of the subjects from the control group responded with a titer of > 50IU/l after 30 days, which suggested an anamnestic response due to prior infection and immunity. Furthermore, 23 subjects in isolated anti-HBc group (47.9%) finally responded after three doses of vaccination (anti-HBs titer > 10IU/l) thus excluding chronic infection and suggesting initial false positive results.

CONCLUSIONS

In isolated anti-HBc subjects false positive results (primary response) or prior infection by HBV (anamnestic response) can be detected by anti-HBs response after HBV vaccination.

Prevalence of hepatitis A virus and hepatitis B virus immunity in patients with polymerase chain reaction-confirmed hepatitis C: implications for vaccination strategy

OBJECTIVES

Administration of vaccine for hepatitis A virus (HAV) and hepatitis B virus (HBV) is recommended for patients with chronic hepatitis C (CHC) because of the potential for increased severity of acute hepatitis superimposed on existing liver disease. The aim of this study is to determine the prevalence of antibodies directed against HAV and HBV in patients with CHC, analyze demographic and risk factors associated with this prevalence, and develop a cost-effective vaccination strategy.

METHODS

We reviewed records from 1092 CHC patients. Demographics and information regarding risk factors were obtained by history and questionnaire administered to all patients. The costs of vaccination and antibody testing were determined, based on standard laboratory and clinic charges at our institution. HAV and HBV markers were correlated to race, age, and risk factors.

RESULTS

Of the total population studied (n = 1092), 72% were African-Americans, 27% white, and 1% others. Of 671 CHC patients tested for anti-HAV IgG, 252 (38%) were positive. Of 743 CHC patients tested for HBV antibodies (anti-hepatitis B core IgG or anti-hepatitis B surface), 494 (67%) were positive. African-Americans are more likely to have antibodies to HAV and HBV (67% and 75%, respectively) compared to whites (27% and 20%). The prevalence of anti-HAV was 76% in patients >60 yr, 34% in the 40- to 60-yr-old age group, and 21% in patients <40 yr. The highest prevalence of HBV antibodies was found in patients between the ages of 40-60 yr. No HCV risk factors were associated with increased HAV risk. In CHC patients with HBV antibodies, however, illicit injection drug use was the predominant risk factor.

CONCLUSIONS

The prevalence of anti-HAV in patients with CHC was found to be similar to that of the general population in the United States (33% according to recent Centers for Disease Control data), consistent with the hypothesis that the two infections do not share risk factors. Because the prevalence of HAV immunity is low in CHC patients <40 yr, empiric HAV vaccination is cost effective. If two doses of vaccine are to be given, however, antibody testing of all HCV patients is indicated. In the subset of patients >60 yr of age or who are African-American, where the prevalence of HAV exposure is considerably higher, it would be cost effective to check the antibody ($36.00), before vaccination ($97.00). The prevalence of HBV antibodies, however, is significantly increased in patients with CHC compared with the general population (5.3% per the Centers for Disease Control), likely as a result of exposure to similar parenteral risk factors. HBV antibody testing ($26.00 per test) should, therefore, be undertaken in all CHC patients who are hepatitis B surface antigen negative, as this approach is cost-effective compared to empiric HBV vaccination ($438.00 for a three injection course).

Hepatitis B core antibody screening in a high prevalence group: comparison of three enzyme immunoassays using receiver operating characteristic analysis

Selected sera from 296 homosexual men were screened by 3 commercially available anti-HBc enzyme immunoassays (EIA). All patients could be classified either as non-immune to hepatitis B, or with current or previous hepatitis B infection. Using the cut-off optical density values (O.D. values) recommended by the respective manufacturers, the results from these three assays were identical for 83% of the serum samples. For anti-HBc reactivity, the ratio (percentage) was calculated using O.D. sample x 100 divided by the O.D. cut-off value. Employing these ratios, sensitivities and specificities for the three assays were compared. All assays performed well when analyzed by receiver operating characteristic curves with area under the curves of 96-97%. A higher specificity, with only a marginal loss of sensitivity could be achieved by lowering the cut-off to 55% for the Enzygost EIA, to 85% for the Enzygost-monoclonal EIA and to 60% for the Corzyme EIA. Using the modified cut-off values, the results with the three assays agreed for 93% of the serum samples.