The Predictive Value of Gut Microbiota Composition for Sustained Immunogenicity following Two Doses of CoronaVac.

CoronaVac immunogenicity decreases with time, and we aimed to investigate whether gut microbiota associate with longer-term immunogenicity of CoronaVac. This was a prospective cohort study recruiting two-dose CoronaVac recipients from three centres in Hong Kong. We collected blood samples at baseline and day 180 after the first dose and used chemiluminescence immunoassay to test for neutralizing antibodies (NAbs) against the receptor-binding domain (RBD) of wild-type SARS-CoV-2 virus. We performed shotgun metagenomic sequencing performed on baseline stool samples. The primary outcome was the NAb seroconversion rate (seropositivity defined as NAb ≥ 15AU/mL) at day 180. Linear discriminant analysis [LDA] effect size analysis was used to identify putative bacterial species and metabolic pathways. A univariate logistic regression model was used to derive the odds ratio (OR) of seropositivity with bacterial species. Of 119 CoronaVac recipients (median age: 53.4 years [IQR: 47.8-61.3]; male: 39 [32.8%]), only 8 (6.7%) remained seropositive at 6 months after vaccination. Bacteroides uniformis (log10LDA score = 4.39) and Bacteroides eggerthii (log10LDA score = 3.89) were significantly enriched in seropositive than seronegative participants. Seropositivity was associated with B. eggerthii (OR: 5.73; 95% CI: 1.32-29.55; p = 0.022) and B. uniformis with borderline significance (OR: 3.27; 95% CI: 0.73-14.72; p = 0.110). Additionally, B. uniformis was positively correlated with most enriched metabolic pathways in seropositive vaccinees, including the superpathway of adenosine nucleotide de novo biosynthesis I (log10LDA score = 2.88) and II (log10LDA score = 2.91), as well as pathways related to vitamin B biosynthesis, all of which are known to promote immune functions. In conclusion, certain gut bacterial species (B. eggerthii and B. uniformis) and metabolic pathways were associated with longer-term CoronaVac immunogenicity.

Role of serum HBV RNA and hepatitis B surface antigen levels in identifying Asian patients with chronic hepatitis B suitable for entecavir cessation.

BACKGROUND: Treatment cessation in chronic HBV infection may be durable in certain patient subgroups before hepatitis B surface antigen (HBsAg) seroclearance. The role of serum HBV RNA in determining treatment cessation suitability has not been well-investigated. METHODS: Nucleos(t)ide analogue (NUC) treatment was discontinued in non-cirrhotic patients with chronic HBV with serum HBsAg <200 IU/mL and fulfilling internationally recommended criteria for treatment cessation. Patients were monitored till 48 weeks with baseline and serial measurements of serum HBsAg, HBV RNA and hepatitis B core-related antigen. NUCs were resumed when HBV DNA reaches >2000 IU/mL regardless of alanine aminotransferase (ALT) levels. RESULTS: 114 entecavir-treated patients (median age 58.4 years, median serum HBsAg 54.4 IU/mL) with median treatment duration of 6.7 years were recruited. The 48-week cumulative rate of HBV DNA >2000 IU/mL was 58.1%. End-of-treatment serum HBV RNA and off-treatment serial HBV RNA were both independently associated with HBV DNA >2000 IU/mL (HR 2.959, 95% CI 1.776 to 4.926, p<0.001; HR 2.278, 95% CI 1.151 to 4.525, p=0.018, respectively). Patients with HBV RNA ≥44.6 U/mL had a cumulative 48-week rate of 93.2%, while combining HBV RNA undetectability and HBsAg <10 IU/mL had a cumulative 48-week rate of 9.1%. 24 patients (38.7%) developed off-treatment ALT elevation, highest peak ALT was 1515 U/L. 8 patients (median serum HBsAg 2.6 IU/mL) developed HBsAg seroclearance. CONCLUSION: Serum HBV RNA measurement is essential for deciding on entecavir cessation in patients with chronic HBV, especially with low HBsAg levels. Patients can be stratified on their risk of off-treatment relapse based on both viral determinants. TRIAL REGISTRATION NUMBER: NCT02738554.

A large real-world cohort study examining the effects of long-term entecavir on hepatocellular carcinoma and HBsAg seroclearance.

Real-world studies examining reduction in risk of hepatocellular carcinoma (HCC) in patients receiving antivirals are limited by the small size of the studies, or by data insufficiency and heterogeneity with short follow-up duration. We aimed to examine the real-world long-term outcome of patients receiving entecavir treatment on HCC incidence and HBsAg seroclearance. The incidence of HCC in 1225 entecavir-treated patients between 2002 and 2015 was compared with the HCC incidence estimated using the REACH-B, GAG-HCC and CU-HCC scores. Standardized incidence ratios (SIR) were calculated. The impact of entecavir treatment on HBsAg seroclearance was also explored. The median follow-up of the cohort was 6.6 years, with 66 cases of HCC development. Using the REACH-B model, the reduction of HCC risk was significant from year 6 onwards with SIR of 0.68 (95% CI 0.535-0.866) at year 10. In subgroup patients without cirrhosis, consistent risk reduction was observed from the fifth year and the SIR reached 0.51 (95% CI 0.271-0.704) by year 10. Benefit in cirrhotic patients was demonstrated when using the GAG-HCC and CU-HCC score, with the SIR at year 10 being 0.38 (95% CI 0.259-0.544) and 0.46 (95% CI 0.314-0.659), respectively. The cumulative rate of HBsAg seroclearance was 5.2%. HBsAg level at third year of treatment and baseline-to-3-year percentage reduction was predictive of subsequent HBsAg seroclearance. In conclusion, long-term entecavir therapy was associated with significant reduction in the risk of HCC in the real world. However, HBsAg seroclearance rate remained low. Additional therapy may be considered in patients with adverse predictive factors for subsequent HBsAg seroclearance.

A Territorywide Prevalence Study on Blood-Borne and Enteric Viral Hepatitis in Hong Kong.

BACKGROUND: Viral hepatitis epidemiological data are important for the World Health Organization plan of eliminating viral hepatitis. We aimed to document the prevalence of viral hepatitis A to E in Hong Kong. METHODS: This community-based study was open to all Hong Kong Chinese citizens aged ≥18 years. Baseline data and risk factors were collected. Hepatitis A-E serology was measured, including hepatitis B e antigen, antibodies to hepatitis B e antigen, antibodies to hepatitis D, hepatitis B virus (HBV) DNA for hepatitis B surface antigen (HBsAg)-positive participants, and antibodies to hepatitis B surface antigen and antibodies to hepatitis B core antigen (anti-HBc) in HBsAg-negative participants. Hepatitis C virus (HCV) RNA and genotypes were determined in anti-HCV-positive participants. RESULTS: A total of 10 256 participants were recruited from February 2015 to July 2016. Overall HBsAg seroprevalence was 7.8% (95% confidence interval [CI], 7.3%-8.3%), which was reduced significantly with HBV vaccination (odds ratio, 0.15 [95% CI, .11-.21]). Among HBsAg-negative participants, anti-HBc seroprevalence increased from 5.4% (<26 years) to 60.1% (>65 years). No hepatitis D virus (HDV) cases were detected. Anti-HCV positivity was 0.5% (95% CI, .3%-.6%). Prevalence of antibodies to hepatitis A virus (anti-HAV) and hepatitis E virus (anti-HEV) was 65.2% (95% CI, 64.2%-66.1%) and 33.3% (95% CI, 32.4%-34.2%), respectively, and were influenced by age, family income, and being born in mainland China. CONCLUSIONS: HBV seroprevalence remained high despite universal vaccination. High anti-HBc seroprevalence underlines the potential issue of HBV reactivation during profound immunosuppression. HCV and HDV remained uncommon. Anti-HAV seroprevalence had decreased whereas anti-HEV seroprevalence had risen.

Hepatitis B core-related antigen levels after HBeAg seroconversion is associated with the development of hepatocellular carcinoma.

Hepatitis B core-related antigen (HBcrAg) is a novel serological marker for hepatitis B virus infection. Its clinical significance after HBeAg seroconversion has not been defined. We aimed to determine the relationship between HBcrAg levels after spontaneous HBeAg seroconversion and hepatocellular carcinoma (HCC). A total of 207 chronic hepatitis B patients with documented time of HBeAg seroconversion were enrolled. HBcrAg and HBsAg were checked within 3 years (as baseline), at 5 and 10 years after HBeAg seroconversion. HBV DNA was measured at the baseline. Multivariate Cox regression model was used to investigate the predictors for HCC development. The median follow-up time was 13.1 (11.8-15.5) years. Fourteen patients developed HCC (15-year cumulative incidence: 7%). The median level of HBcrAg at baseline was significantly higher in patients who developed HCC when compared with patients without HCC (5.68 vs 4.78 log U/ml, respectively; P = .003). Cox proportional hazards model indicated that age of HBeAg seroconversion older than 40 years (hazard ratio (HR): 4.60; P = .049), presence of baseline cirrhosis (HR: 6.23; P = .003) and a higher baseline HBcrAg (HR: 1.75; P = .032) were independently associated with HCC development. A cut-off value of baseline HBcrAg level ≥5.21 log U/mL yielded an AUROC of 0.74 with a negative predictive value of 97.7%. High HBcrAg levels within 3 years after HBeAg seroconversion were independently associated with the development of HCC in chronic hepatitis B patients.

Long-term outcomes and predictive scores for hepatocellular carcinoma and hepatitis B surface antigen seroclearance after hepatitis B e-antigen seroclearance.

The significance of hepatitis B e-antigen (HBeAg) seroclearance (ESC) in the long term is not well defined. The current study aimed to determine the clinical outcomes, the factors and predictive scores for hepatocellular carcinoma (HCC), and hepatitis B surface antigen (HBsAg) seroclearance of a large cohort of patients undergoing ESC. Patients with documented ESC were followed up 3- to 6-monthly. Baseline characteristics and longitudinal laboratory results were recorded. Predictive scores for HCC (HCC-ESC) and HBsAg seroclearance (HBsAg-ESC) were derived from multivariate Cox regression models. A total of 723 patients underwent ESC with a median ESC age and follow-up of 36.0 and 18.3 years, respectively. Only 3.5% and 3.0% had persistently normal alanine aminotransferase (ALT) and HBV DNA <2logs IU/mL, respectively, after ESC. For patients with 100%, 100%-90%, 90%-50%, 50%-10%, 10%-0%, and 0% normal ALT after HBeAg seroclearance, the rate of HCC was 4.3%, 2.2%, 3.6%, 3.9%, 17.3%, and 37.2% at 20 years after ESC, respectively (P < 0.001). At 20 years after ESC, the cumulative incidence of HCC and HBsAg seroclearance was 7.9% and 13.5%, respectively, with an overall survival of 91.5%. ESC age, male sex, cirrhosis, hypoalbuminemia, viral load, and ALT were significant factors for HCC, whereas ESC age, male sex, viral load, and antiviral therapy were significant factors for HBsAg seroclearance. The area under receiver operating characteristics for HCC-ESC and HBsAg-ESC scores to predict HCC and HBsAg seroclearance at 20 years after ESC was 0.92 and 0.74, respectively. CONCLUSION: Male sex, older age at ESC, ALT, and higher level of HBV DNA were associated with higher rates of HCC after ESC. HCC-ESC and HBsAg-ESC predictive scores can determine the likelihood of developing HCC and achieving HBsAg seroclearance. (Hepatology 2018).

Attitudes and perceptions of influenza vaccination among Hong Kong doctors and medical students before the 2009 pandemic.

BACKGROUND: Vaccination is an important preventive measure for preparing against the influenza pandemics. This study investigated the attitudes and perceptions of influenza vaccination among doctors and medical students in Hong Kong. METHODS: A cross-sectional survey was conducted among 204 doctors and 242 medical students in a teaching hospital in 2009. Participants' demographic and job characteristics, and influenza experience and vaccination in the previous year were assessed in the questionnaire. Logistic regression models were used to examine the associations between uptake of influenza vaccination and the perceived benefits. RESULTS: Medical students were more likely to have receive an influenza vaccination in the previous year (66.9 vs. 39.7%) and acknowledged the related benefits than doctors. Moreover, uptake of influenza vaccine was associated with perceived benefits of vaccination in both doctors and medical students. CONCLUSIONS: The perceived benefits of influenza vaccination are an important factor in vaccine uptake for both doctors and medical students in Hong Kong, and should be reinforced in the professional training.

Association between Recent Usage of Antibiotics and Immunogenicity within Six Months after COVID-19 Vaccination.

Background: Gut microbiota can be associated with COVID-19 vaccine immunogenicity. We investigated whether recent antibiotic use influences BNT162b2 vaccine immunogenicity. Methods: BNT162b2 recipients from three centers were prospectively recruited. Outcomes of interest were seroconversion of neutralising antibody (NAb) at day 21, 56 and 180 after first dose. We calculated the adjusted odds ratio (aOR) of seroconversion with antibiotic usage (defined as ever use of any antibiotics within six months before first dose of vaccine) by adjusting for covariates including age, sex, smoking, alcohol, and comorbidities. Results: Of 316 BNT162b2 recipients (100 [31.6%] male; median age: 50.1 [IQR: 40.0-57.0] years) recruited, 29 (9.2%) were antibiotic users. There was a trend of lower seroconversion rates in antibiotic users than non-users at day 21 (82.8% vs. 91.3%; p = 0.14) and day 56 (96.6% vs. 99.3%; p = 0.15), but not at day 180 (93.3% vs. 94.1%). A multivariate analysis showed that recent antibiotic usage was associated with a lower seroconversion rate at day 21 (aOR 0.26;95% CI: 0.08-0.96). Other factors associated with a lower seroconversion rate after first dose of the BNT162b2 vaccine included age ≥ 60 years (aOR: 0.34;95% CI: 0.13-0.95) and male sex (aOR: 0.14, 95% CI: 0.05-0.34). There were no significant factors associated with seroconversion after two doses of BNT16b2, including antibiotic use (aOR: 0.03;95% CI: 0.001-1.15). Conclusions: Recent antibiotic use may be associated with a lower seroconversion rate at day 21 (but not day 56 or 180) among BNT162b2 recipients. Further long-term follow-up data with a larger sample size is needed to reach a definite conclusion on how antibiotics influence immunogenicity and the durability of the vaccine response.

Entecavir Reduced Serum Hepatitis B Core-Related Antigen in Chronic Hepatitis B Patients with Hepatocellular Carcinoma.

Serum hepatitis B core-related antigen (HBcrAg) was shown to predict the risk of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients undergoing treatment. We investigated the longitudinal profile of HBcrAg in entecavir (ETV)-treated CHB patients with subsequent HCC development. We identified HCC cases diagnosed at ≥1 year after ETV initiation. CHB patients without HCC (matched for age, sex, cirrhosis status, baseline hepatitis B virus [HBV] DNA level, and ETV treatment duration) were identified as controls at an HCC:non-HCC ratio of 1:2. Serum samples were retrieved at baseline (ETV initiation) and at 3 and 5 years of ETV therapy for HBcrAg measurement (log IU/mL). In total, 180 patients (60 HCC patients matched with 120 CHB patients without HCC; median age, 56.5 years; 80.6% male; baseline HBV DNA, 5.9 log IU/mL; median follow-up, 6.8 years) were recruited. The median time from ETV initiation to HCC development was 3.2 years. HBcrAg levels were higher in HCC cases than in controls at all three time points: 5.69 log IU/ mL versus 5.02 log IU/mL (p=0.025), 4.23 log IU/mL versus 3.36 log IU/mL (p=0.007), and 3.86 log IU/mL versus 3.36 log IU/mL (p=0.009), respectively. ETV led to similar rates of decline in HBcrAg from baseline to 3 years in both groups (0.34 log IU/mL/year vs 0.39 log IU/mL/year, p=0.774), although the decline from 3 to 5 years was slower in the non- HCC group (0.05 log IU/mL/year) than in the HCC group (0.09 log IU/mL/year, p=0.055). ETV time-dependently reduced HBcrAg in HCC and non-HCC patients. HBcrAg interpretation should consider the antiviral treatment duration.

Serum Mac-2 binding protein glycosylation isomer level predicts hepatocellular carcinoma development in E-negative chronic hepatitis B patients.

BACKGROUND: Liver cirrhosis is a major risk factor for hepatocellular carcinoma (HCC) development in chronic hepatitis B (CHB). Serum Mac-2 binding protein glycosylation isomer (M2BPGi) is a novel serological marker for fibrosis. The role of M2BPGi in prediction of HCC is unknown. AIM: To examine the role of serum M2BPGi in predicting HCC development in hepatitis B e antigen (HBeAg)-negative patients. METHODS: Treatment-naive CHB patients with documented spontaneous HBeAg seroconversion were recruited. Serum M2BPGi was measured at baseline (within 3 years from HBeAg seroconversion), at 5 years and 10 years after HBeAg seroconversion and expressed as cut-off index (COI). Multivariate cox regression was performed to identify predictors for HCC development. ROC analysis was used to determine the cut-off value of M2BPGi. RESULTS: Among 207 patients (57% male, median age at HBeAg seroconversion 40 years old) with median follow-up of 13.1 (11.8-15.5) years, the cumulative incidence of HCC at 15 years was 7%. Median M2BPGi levels were significantly higher in patients with HCC compared to those without HCC (baseline: 1.39 COI vs 0.38 COI, P < 0.001; 5-year: 1.45 COI vs 0.47 COI, P < 0.001; 10-year: 1.20 COI vs 0.55 COI, P = 0.001). Multivariate analysis revealed age at HBeAg seroconversion [odds ratio (OR) = 1.196, 95% confidence interval (CI): 1.034-1.382, P = 0.016] and baseline M2BPGi (OR = 4.666, 95%CI: 1.296-16.802, P = 0.018) were significant factors predictive of HCC. Using a cut-off value of 0.68 COI, baseline M2BPGi yielded AUROC of 0.883 with 91.7% sensitivity and 80.8% specificity. CONCLUSION: High serum M2BPGi within 3 years after HBeAg seroconversion was a strong predictor for subsequent HCC development in treatment-naive HBeAg-negative CHB patients.

Infection-related hospitalizations in the first year after inflammatory bowel disease diagnosis.

OBJECTIVE: With the rapid increase in the incidence of inflammatory bowel disease (IBD) in Asia, the natural course of the early phase of disease in these patients remains poorly defined. This study aimed to determined the incidence and characteristics of infection-related hospitalization in the first year in patients newly diagnosed with IBD in Hong Kong SAR, China. METHODS: Patients newly diagnosed with IBD and enrolled in the territory-wide Hong Kong IBD Registry were identified. Details of their hospitalization within the first 12 months after diagnosis were retrieved and analyzed. RESULTS: Altogether 433 newly diagnosed IBD patients were enrolled, including 188 with Crohn's disease (CD), 230 with ulcerative colitis (UC) and 15 with IBD-unclassified (IBD-U). Among them, 110 (25.4%) had at least one unscheduled hospitalization in the first year and 34 (7.9%) had infection-related hospitalization, leading to 43 (23.4%) of total hospitalizations. Gastrointestinal tract (30.2%), respiratory tract (34.9%) and skin and soft tissues (11.6%) were the most common sites of infection. Bacterial and viral infections accounted for 46.7% and 20.8% of hospitalizations for infection, respectively. Common identified pathogens included Clostridium difficile (16.3%) and Cytomegalovirus (11.6%). Multivariate analysis found that patient's age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.06) and the presence of comorbidity (OR 2.32, 95% CI 1.05-5.13) were significantly associated with hospitalization from infection in IBD patients. CONCLUSIONS: Infection-related hospitalizations were found in 7.9% of newly diagnosed IBD patients within the first year after diagnosis in Hong Kong, which accounted for about one-quarter of all unscheduled hospitalizations. Elder patients with concurrent illnesses were at higher risk.