Hepatitis B virus infection in Singapore

Approach to Abnormal Liver Biochemistries in the Primary Care Setting

Liver biochemistries are commonly ordered in the primary care setting, and they may return abnormal even in an asymptomatic patient. Primary care physicians need to have a systematic way of interpreting any derangement in these tests so that further investigations, referrals, and management can be arranged appropriately. This review dwells into patterns of liver biochemistry derangement, common aetiologies to consider, history and examinations that are required, initial investigations to order, and when to refer urgently to the emergency department.

Failure of sterilization in a dental outpatient facility: Investigation, risk assessment, and management

In 2017, an incident of failed sterilization of dental instruments occurred at a large dental outpatient facility in Singapore. We aim to describe findings of the investigation of the sterilization breach incident, factors related to risk of viral transmission to the potentially affected patients, and the contact tracing process, patient management, and blood test results at a 6-month follow-up. A full assessment of the incident was immediately carried out. The factors related to risk of viral transmission due to affected instruments were analyzed using 3 keys points: breached step(s) and scale of the incident, prevalence of underlying bloodborne diseases and immunity in the Singapore population, health status of potential source patients, and type of dental procedure performed, and health status of affected patients and type of dental procedure received. Up to 72 affected instrument sets were used in 714 potentially affected patients who underwent noninvasive dental procedures. The investigation revealed that there was a lapse in the final step of steam sterilization, resulting in the use of incompletely sterilized items. The assessment determined that there was an extremely low risk of bloodborne virus transmission of diseases to the patients. At the 6-month follow-up, there were no infected/colonized cases found related to the incident. Lapses in the sterilization process for medical and dental instruments can happen, but a risk assessment approach is useful to manage similar incidents. Quick response and proper documentation of the sterilization process can prevent similar incidents.

Hepatitis B Virus Seropositivity Is a Poor Prognostic Factor of Pediatric Hepatocellular Carcinoma: a Population-Based Study in Hong Kong and Singapore

Background

Hepatocellular carcinoma (HCC) is a rare hepatic malignancy in children. Hepatitis B virus (HBV) infection is a key predisposing factor in endemic regions but its impact on outcome has not been studied. We aim to evaluate the prognostic implication of HBV seropositivity and role of cancer surveillance in children with HCC from East Asian populations with national HBV vaccination.

Methods

Review of population-based databases for patients (< 18 years old) diagnosed with HCC from 1993 to 2017 in two Southeast Asian regions with universal HBV vaccination (instituted since 1988 and 1987 in Hong Kong and Singapore, respectively).

Results

Thirty-nine patients were identified (Hong Kong, 28; Singapore, 11). Thirty were male; median age at diagnosis was 10.8 years (range, 0.98-16.6). Abdominal pain was the commonest presentation while five patients were diagnosed through surveillance for underlying condition. Alpha-fetoprotein was raised in 36 patients (mean, 500,598 ng/ml). Nineteen had bilobar involvement, among the patients in whom pretreatment extent of disease (PRETEXT) staging could retrospectively be assigned, 3 had stage I, 13 had stage II, 4 had stage III, and 11 had stage IV disease. Seventeen had distant metastasis. HBsAg was positive in 19 of 38 patients. Two patients had fibrolamellar HCC. Upfront management involved tumor resection in 16 (liver transplantation, 2), systemic chemotherapy in 21, interventional procedures in 6 [transarterial chemoembolization (TACE), 5, radiofrequency ablation (RFA), 1], and radiotherapy in 4 (selective internal radiation, 3, external beam radiation, 1). Five-year event-free survival (EFS) and overall survival (OS) were 15.4 ± 6.0 and 26.1 ± 7.2%, respectively. Patient's HBsAg positivity, metastatic disease and inability to undergo definitive resection represent poor prognostic factors in univariate and multivariable analyses. Patients diagnosed by surveillance had significantly better outcome.

Conclusion

Pediatric HCC has poor outcome. HBV status remains relevant in the era of universal HBV vaccination. HBV carrier has inferior outcome and use of surveillance may mitigate disease course.

A sonographic Doppler study of the hepatic vein, portal vein and hepatic artery in liver cirrhosis: Correlation of hepatic hemodynamics with clinical Child Pugh score in Singapore

Objective

Liver cirrhosis has been a rising complication of chronic liver disease in Singapore. Ultrasound has been widely accepted as a non-invasive imaging modality for the evaluation of hepatic haemodynamics. This study aims to correlate the Doppler ultrasound values with the progression of liver cirrhosis to allow further understanding and possible prediction of clinical events for timely intervention.

Methods

Study sample of 56 eligible patients with liver cirrhosis was divided according to their Child-Pugh clinical score into Child's A (n = 29 patients), B (n = 19 patients) and C (n = 8 patients). The maximum portal vein velocity, maximum hepatic vein velocity, maximum hepatic artery velocity and hepatic artery resistive index were assessed by Doppler ultrasound.

Results

The incidence of ascites increases with the severity of cirrhosis. Flattening of the hepatic vein waveforms was dependant on degree of liver cirrhosis. Maximum hepatic vein velocity was higher in cirrhotic patients (where p = 0.05). Maximum portal vein velocity was found to be lower in cirrhosis (where p < 0.001) and mean maximum portal vein velocity decreases as severity of cirrhosis worsens. Hepatic artery resistive index was significantly higher in cirrhosis (where p < 0.001). Significant association was found between maximum hepatic vein velocity and maximum hepatic artery velocity and significant negative correlation was observed with the maximum portal vein velocity and hepatic artery resistive index.

Conclusion

The study demonstrated that these parameters can supplement the evaluation of liver cirrhosis and will be able to distinguish the different grades of liver cirrhosis using Doppler ultrasound.

Time for Action on Viral Hepatitis

The recent outbreak of hepatitis C virus (HCV) at Singapore General Hospital (SGH) has highlighted the dangers of viral hepatitis. In this case, infection control and environmental contamination were the culprits, particularly, a drop of blood containing 5 million IU HCV. From a broader perspective, there has been a revolution in HCV therapy with the recent rapid evolution of short-term (12 weeks) safe, all oral directly-acting antiviral (DAA) therapy leading to cure rates of 90% to 100%, even in previously difficult to treat patients with liver cirrhosis, previous treatment failure and those on immunosuppression. Consequently, treating HCV in risk groups such as renal dialysis and haemophiliacs can eliminate a pool of infected patients to prevent future outbreaks. A seroprevalence study is needed to identify a possible “birth cohort” effect that could aid screening. For HBV, vaccination has reduced prevalence to 3.8%, but these patients are prone to complications such as HBV flares. Since 2014, 13 patients developed liver failure and were listed for liver transplantation at National University Hospital (NUH) but 6 died beforehand. This avoidable catastrophe is due to undiagnosed HBV infection or patients who did not return for follow-up. Good antiviral therapy is available, but the issues are similar to HCV, identification of patients and linkage to care. A cure seems likely in the future as pharmaceutical companies are developing new agents. Singapore has joined in this initiative with a recent award of a national research translational grant to better understand the pathophysiology and the processes needed for a cure of HBV. Key words: Eradication, Hepatitis C, Linkage to care, Outbreaks, Screening, Treatment

Hepatitis B virus reactivation risk varies with different chemotherapy regimens commonly used in solid tumours

Background:

Hepatitis B virus (HBV) reactivation may occur with chemotherapy and has significant morbidity and mortality. The United States Centre for Disease Control and Prevention recommends pre-chemotherapy hepatitis B screening for all cancer patients, while the American Society of Clinical Oncology finds that there is insufficient evidence currently to support such a recommendation. Apart from anthracyclines, HBV reactivation rates from other commonly used chemotherapy regimens in solid tumours are not well described.

Methods:

We compared HBV reactivation risk in patients receiving several commonly used chemotherapy regimens for solid tumours associated with different immunosuppression risk at a tertiary cancer centre in an HBV endemic region.

Results:

A total of 1149 patients were identified, including 434, 196, 245 and 274, respectively, who received doxorubicin-based, oxaliplatin- or irinotecan-based, carboplatin/gemcitabine, and capecitabine chemotherapy. HBV screening rate was 39% overall. Thirty out of 448 (7%) screened patients were HBsAg positive and 28 out of 30 received prophylactic antiviral therapy with no reactivation. Three out of 1149 patients overall (0.3%) developed HBV reactivation, all from the unscreened doxorubicin group (3 out of 214, 1.4%). No unscreened patients (0 out of 487) in the other three treatment groups developed reactivation (P<0.001).

Conclusion:

Not all chemotherapy regimens result in HBV reactivation. Routine hepatitis B screening for low- or moderate-risk regimens may not be warranted.

Epidemiology and molecular characterization of hepatitis B virus infection in isolated villages in the Western Brazilian Amazon

Individuals from three isolated, rural communities in the western Brazilian Amazon were evaluated for serological markers of hepatitis B virus (HBV) infection, HBV genotype, and the presence of risk factors for infection and transmission. Of the 225 individuals studied, 79.1% had serological evidence of HBV infection; 10.2% individuals were chronic carriers for HBV surface antigen (HBsAg-positive). Analysis of risk factors indicates that HBV is transmitted mainly horizontally within the family from a chronic "active" carrier for hepatitis B "e" antigen (HBeAg-positive), though a strong possibility of vertical transmission remains. The predominance of HBV genotype F, with a higher genomic similarity between the isolates, indicated a relatively recent introduction of HBV, from a common source, to the area. This study sheds light on the HBV epidemiology in the Brazilian Amazon region and highlights the need for greater emphasis on HBV control and immunization programs.

How big is the financial burden of hepatitis B to society? A cost-of-illness study of hepatitis B infection in Singapore

Hepatitis B virus (HBV) infection is the most common cause of chronic viral liver disease in Singapore. Nevertheless, very little data exist on the financial burden of HBV infection to the society as a whole. The aim of this study was therefore to assess the direct and indirect cost of HBV infection in a cost-of-illness analysis. The combined data from the direct and indirect cost with the estimated prevalence for different disease stages of HBV infection would represent the annual financial burden of HBV infection to the Singaporean society as a whole. The estimated total annual cost of chronic HBV infection and its associated complications in Singapore was US$279 million (range US$34-941 million when allowing various assumptions as tested by the sensitivity analyses), with 58% or US$161 million attributable to direct cost. Based on the base-case estimation, total direct cost alone is equivalent to 12% of the national healthcare expenditure for 2003. The total cost incurred by chronic hepatitis B patients represents the biggest cost component, followed by decompensated cirrhosis (DC) patients. The ratio of direct to indirect costs based on the base-case estimation increased with disease severity, with the highest ratio obtained for the post-liver transplants (40.2:1), followed by hepatocellular carcinoma (7.4:1) and DC patients (2.7:1). The results of this study suggest that the management of HBV infection poses more than a medical challenge as it is a sizeable economic burden from both the payer and societal perspectives.

Outcomes of Chronic Hepatitis B Infection in Oriental Patients with Rheumatic Diseases

Introduction: The aim of this study was to ascertain the outcomes of chronic hepatitis B (CHB) infection following immunosuppressive therapy in 38 consecutive oriental patients with systemic rheumatic diseases. Materials and Methods: This is a retrospective consecutive, non-comparative study. Results: The majority of patients were female (26, 68.4%), predominantly Chinese (92.1%), with a mean age 54 ± 14 years (range, 16 to 87). The mean duration of rheumatic disease was 9 ± 11 years (range, 0.1 to 48), with rheumatoid arthritis (52.6%) and systemic lupus erythematosus (23.7%) being the most common. The mean duration of CHB infection was 6 ± 5 years (range, 0.1 to 17), with the majority diagnosed during pre-methotrexate screening (50.0%) and asymptomatic transaminitis following initiation of immunosuppressive therapy (23.7%). Upon diagnosis of rheumatic disease, all patients had normal alanine aminotransferase (ALT). Of these, 18.2% were positive for hepatitis B e antigen (HBeAg) and 78.1% were positive for anti-HBe antibody. Twenty (52.6%) developed ALT elevation, which was more than twice the upper limit of normal in 12 patients. ALT normalised spontaneously in 12 patients without hepatic decompensation or change in therapy. Seven (18.4%) patients received lamivudine for 18 ± 22 months (range, 2 to 61). Two patients developed YMDD mutation subsequently treated with adefovir (1) and adefovir/lamivudine (1). There were 3 (7.9%) hepatitis B virus (HBV)-unrelated deaths [infection (2), genitourinary malignancy (1)], and 1 from HBV-reactivation complicated by septicaemia. None have developed hepatocellular carcinoma. Conclusion: Elevated ALT occurred in 52.6% of patients, with only 18.4% requiring anti-viral therapy for HBV reactivation. HBV-related mortality was low. With the appropriate precautionary measures, prednisolone and immunosuppressants (except methotrexate and leflunomide) may be used safely in patients where clinically indicated. Key words: Ankylosing spondylitis, Lamivudine, Rheumatoid arthritis, Spondyloarthropathies

Impact of the Expanded Program of Immunization against hepatitis B infection in school children in Malaysia

The implementation of the Expanded Program of Immunization (EPI) in 1989 has dramatic impact on hepatitis B virus (HBV) infection in school children in Malaysia. A cross-sectional seroprevalence study of HBV infection in 190,077 school children aged 7-12 years from 1997 to 2003 showed a steady decline of HBV surface antigen (HBsAg) prevalence rate from 2.5% for children born in 1985 to 0.4% among school children born in 1996. The overall prevalence of HBsAg was 0.6%, 0.7% in males and 0.6% in females. Over 92.7% of school children had been vaccinated with HBV vaccine, in which 93.7% were vaccinated under the EPI and 6.3% on voluntary basis. The school children vaccinated under EPI had a 0.4% HBsAg carrier rate, which was significantly lower than school children vaccinated on a voluntary basis (HBsAg carrier rate 1.3%) and non-vaccinated school children (HBsAg carrier rate 2.7%), suggesting that HBV vaccination of infants was the most effective measure in preventing vertical transmission of HBV in the hyperendemic region.

Long-term efficacy of hepatitis B vaccine, booster policy, and impact of hepatitis B virus mutants

The long-term efficacy of hepatitis B vaccine, long-term effectiveness of hepatitis B immunisation programmes, immune memory induced by hepatitis B vaccine, current booster policies, and impact of hepatitis B virus mutants on immunisation programmes were reviewed at the Viral Hepatitis Prevention Board (VHPB) meeting in Sevilla, Spain, March 2004. The main focus was on universal vaccination programmes with data being presented from Italy, Saudi Arabia, Singapore, Spain, Taiwan, Thailand, The Gambia, and USA (Alaska).

Practical difficulties in the management of hepatitis B in the Asia-Pacific region

The Asia-Pacific Expert Committee on Hepatitis B Management recently reviewed the impact of hepatitis B in the region and assessed the differences and similarities observed in the practical management of the disease in individual Asia-Pacific countries. Hepatitis B is a major health concern in the Asia-Pacific region, and of all chronically infected carriers worldwide, approximately 75% are found in Asia. The disease poses a considerable burden on healthcare systems, and is likely to remain a cause of substantial morbidity and mortality for several decades. Disease prevention activities, including screening and vaccination programs, have been implemented successfully in some Asia-Pacific countries and similar measures are being established in other parts of the region. The management of hepatitis B in the Asia-Pacific varies throughout the region, with each country confronting different issues related to treatment options, disease monitoring and duration of therapy. The influence of cost, availability of diagnostic equipment, and patient awareness and compliance are of additional concern. Although guidelines such as those developed by the Asian Pacific Association for the Study of the Liver have been created to address problems encountered in the management of hepatitis B, many physicians in the region still find it difficult to make satisfactory management decisions because of the treatment choices available. This article examines the different approaches to hepatitis B management in a number of Asia-Pacific countries, and highlights the difficulties that can arise when adhering to treatment guidelines and disease prevention solutions that have proved to be successful in the region.

Histological spectrum of chronic hepatitis in precore mutants and wild-type hepatitis B virus infection

This study compares the histology of liver biopsies in precore mutant (PCM) and wild-type hepatitis B virus (HBV) infection. Thirty cases of PCM and 60 cases of wild-type HBV infection were included. Patients were diagnosed on the basis of serological profile and HBV DNA assessment. Liver biopsies in each case were assessed for histological activity and stage of fibrosis using a modification of Knodell's scoring system. There was no statistically significant (P=0.14) difference in histological activity in the two groups. The difference in stage of fibrosis in the two groups was statistically significant (P=0.001). Quantitative estimation of viral load did not show any correlation with liver histology. PCM HBV showed greater stage of fibrosis compared with wild-type infection, and this may be related to disease progression and lack of response to therapy.

Sero-epidemiology and risk factors of positive hepatitis B surface antigen amongst Chinese adolescents

This paper reports the prevalence rate of hepatitis B antigen (HBsAg) amongst the Hong Kong Chinese adolescents (age 11 to 19), and the risk factors associated with HBsAg positive. The study is cross sectional and 1,580 students were randomly selected from 12 secondary schools in four regions of Hong Kong. For those subjects who agreed to participate and were randomly selected, their blood was tested for HBsAg and anti-HBs. The overall prevalence of HBsAg positive was reported to be 5.8% (7.9% in male and 4.1% in female), lower than 8.1% in 1978. Males, those born in Mainland China and family history of carriers had higher prevalence of HBsAg positive (7.9% vs 4.1%, 12.2% vs 4.7%, 52.9% vs 3.8% respectively) with statistical significance. Males and those born in mainland China were found to have significantly higher odds ratio 1.8 (95% CI. 0.98-3.52) and 4.4 (95% CI. 2.2-8.8) respectively of HBsAg positive by multivariate analysis. Findings suggest that family history of carriers and those born in endemic area are at a higher risk. Therefore it is worthwhile to consider vaccination programme for adolescents to reduce the carrier rate, and to also reduce the injection amongst the adults by horizontal transmission.

Hepatitis B virus infection in Thai children

We studied hepatitis B virus (HBV) transmission among 7416 Thai children from 148 schools in Kamphaeng Phet province, a rural part of northern Thailand. Their age ranged from 2 to 16 years (median 9 years). Between May 1991 and June 1992, 61 of 2593 (2.4%) in the cohort of susceptible children acquired anti-HBc immunoglobulin. Forty-seven of the 148 schools had children who acquired anti-HBc. School seroconversion rates to anti-HBc varied from 0% to 23%. There was no correlation between percent of carriers in schools and percent of anti-HBc acquisition. Of the 61 children who acquired anti-HBc, eight (13%) became HBsAg carriers but only two were symptomatic, for a clinical to subclinical infection ration of 1 : 30. One of the two symptomatic children became an HBsAg carrier. Three (38%) of the eight who were persistently antigenemic developed antibody to hepatitis B virus e antigen. Males were 2.5 times (95% CI 1.4-4.3) more likely to acquire anti-HBc than females. Risk factors for acquisition of HBc in Thailand over a 9-month period were examined in a subset of 2412 susceptible children and later in a case-control study of 22 children who acquired anti-HBc and 59 age and sex-matched controls. Risks for acquiring anti-HBc were male gender and a history of bleeding gums. In comparing this study to an earlier pilot study among 9848 children from the same area in Thailand, the yearly antibody acquisition rate to anti-HBc among Thai children dropped from 5.7% in 1989 to 2.4% in 1992. A random sample of children in the pilot study showed that 16% were HBsAg positive and 27% had anti-HBc at the beginning of the study. 34% had markers for either anti-HBc or HBsAg. 12% were repeatedly positive for HBsAg a year later.