HBV infection in indigenous children, 20 years after immunization in Taiwan: a community-based study

Risk of HBV infection among male and female first-time blood donors born before and after the July 1986 HBV vaccination program in Taiwan

Background

In July 1984, Taiwan officially began a nationwide hepatitis B virus (HBV) vaccination program where only infants born to HBsAg-positive mothers were vaccinated free of charge until June 1986. However, from July 1986, all infants were vaccinated against HBV. The impact of the July 1986 HBV vaccination program on first-time blood donors has not been exhaustively studied. We, therefore, determined the risk of HBV among male and female first-time blood donors born before and after the July 1986 HBV vaccination program in Taiwan.

Methods

Initially, we recruited 857,310 first-time blood donors whose data were collected between 2013 and 2018 from 5 blood donation centers in Taiwan. However, we excluded donors with incomplete and outlying data (n = 12,213) and those born between July 1984 and June 1986 (n = 21,054). The final study participants comprised 9118 HBV positive and 814,925 HBV negative individuals. We divided the participants into two birth cohorts (born before and after July 1986) and assumed that those born before July 1986 were not vaccinated at birth while those born after July 1986 were vaccinated.

Results

The prevalence of HBV among those born before and after July 1986 was 4.53 and 0.25%, respectively. Individuals born after July 1986 had a lower risk of HBV than those born before July 1986. The adjusted odds ratio (OR), 95% confidence interval (CI) was 0.16, 0.13–0.19. Men had a higher risk of HBV than women (OR = 1.40, 95% CI = 1.34–1.47). The interaction between sex and birth date was significant (p-value = 0.0067). Stratification of participants by birth date revealed a higher risk of HBV in men compared to women in both birth cohorts. The OR, 95% CI was 1.47, 1.40–1.55 for those born before July 1986 but declined to 1.15, 1.02–1.29 for those born after July 1986.

Conclusions

The risk of HBV was lower among those born after than those born before the July 1986 vaccination program. In both cohorts, the risk was high in men relative to women. The seemingly protective effect among those born after July 1986 was higher in women than men.

The evolution and clinical impact of hepatitis B virus genome diversity

The global burden of hepatitis B virus (HBV) is enormous, with 257 million persons chronically infected, resulting in more than 880,000 deaths per year worldwide. HBV exists as nine different genotypes, which differ in disease progression, natural history and response to therapy. HBV is an ancient virus, with the latest reports greatly expanding the host range of the Hepadnaviridae (to include fish and reptiles) and casting new light on the origins and evolution of this viral family. Although there is an effective preventive vaccine, there is no cure for chronic hepatitis B, largely owing to the persistence of a viral minichromosome that is not targeted by current therapies. HBV persistence is also facilitated through aberrant host immune responses, possibly due to the diverse intra-host viral populations that can respond to host-mounted and therapeutic selection pressures. This Review summarizes current knowledge on the influence of HBV diversity on disease progression and treatment response and the potential effect on new HBV therapies in the pipeline. The mechanisms by which HBV diversity can occur both within the individual host and at a population level are also discussed.

Seroprevalence and clinical characteristics of viral hepatitis in transfusion-dependent thalassemia and hemophilia patients

BACKGROUND/AIMS

Transfusion dependent subjects are at a great risk of viral hepatitis infection. We aimed to evaluate the prevalence and factors associated with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection among transfusion-dependent patients in Taiwan.

METHODS

A total of 140 patients (67 thalassemic patients, 70 hemophilic patients, two patients with hereditary spherocytosis and one patient with von Willebrand disease) were prospectively enrolled to evaluate the prevalence and factors associated with viral hepatitis and spontaneous HCV clearance. All patients were tested for HBV and HCV serology and virology. Two consecutive serum samples, at least 1 year apart, were collected to clarify HCV seroclearance.

RESULTS

The seropositivity rate of hepatitis B surface antigen (HBsAg), HCV antibody (anti-HCV), and both HBsAg/anti-HCV were 6.4%, 45.7% and 5%, respectively. Logistic regression analysis of factors associated with anti-HCV seropositivity included age (odds ratio/95% confidence interval [OR/CI]: 1.12/1.07-1.18, P<0.001), serum alanine aminotransferase (ALT) (OR/CI: 1.04/1.02-1.06, P<0.001) and platelet counts (OR/CI: 0.995/0.991-0.998, P = 0.002). Age was the only factor independently associated with HBsAg seropositivity (OR/CI: 1.08/1.02-1.14.4, P = 0.007). Compared to patients born before 1992, the seroprevalence of HCV among thalassemic patients decreased dramatically in those born after 1992 (46.0% vs. 11.8%, p = 0.012). The seroprevalence of HCV among hemophilic patients also decreased significantly when comparing patients born before 1987 to those born after 1987 (79.5% vs. 11.5%, p<0.001). Similarly, the seroprevalence of HBV decreased significantly in the post-vaccination cohort compared to its counterpart (13.1%, vs. 1.3%, p = 0.005). The spontaneous clearance of HCV was observed in 25.4% (15/59) of patients, and ALT was the only factor associated with it (OR/CI 0.98/0.96-1.00, P = 0.02).

CONCLUSIONS

Both HBV and HCV infections are prevalent among transfusion-dependent thalassemic and hemophilic patients in Taiwan. Nevertheless, seroprevalence decreased significantly and dramatically for HCV after universal blood screening and for HBV after implementation of a universal mass vaccination program.

Hepatitis B Seroprotection and the Response to a Challenging Dose among Vaccinated Children in Red Sea Governorate

AIM:

To assess the long-term effectiveness of hepatitis B virus vaccine and the need for a booster dose among children who received three doses of vaccine during infancy in Red Sea Governorate.

METHODS:

A cross-sectional study was performed. Interviews with children (9 months to 16 years) and parents were done. Blood samples to assess Hepatitis B markers were tested. Children showing no seroprotection received a booster dose to assess their anamnestic response after four weeks and one year later.

RESULTS:

None of the participants had evidence of chronic Hepatitis B. The seroprotection rate was 23.3% and it significantly decreased with age. Multivariate logistic analysis revealed that older age was the significant predicting variable for having no seroprotective level, while baseline anti-HBs level < 3.3 IU/L was the predicting variable for not developing early anamnestic response or loss of late anamnestic response.

CONCLUSION:

Long-term immunity persists among children who received complete series of hepatitis B vaccination during infancy even in absence or reduction of anti-HBs over time. Therefore, a booster dose is not necessary to maintain immunity till the age of sixteen.

The Serum Anti-HBs Level Among Children Who Received Routine Hepatitis B Vaccination During Infancy in Mianyang City, China: A Cross-Sectional Study

Hepatitis B virus (HBV) prevalence has declined remarkably in children due to nationwide universal vaccination program for HBV in China. However, the persistence of immune response against HBV infection and the optimal time point when a booster vaccination should be performed remain to be elucidated. To assess the persistence and level of antibody against hepatitis B surface antigen (anti-HBs) in a representative population of age 15 and younger who received routine hepatitis B vaccination in Mianyang City, China. A cross-sectional study was conducted in 2011. One thousand five hundred twenty-six children of age 15 and younger who received three doses of 5 μg hepatitis B vaccine series during infancy but did not receive a booster vaccination later were enrolled. Of the 1,526 children, the mean age was 8.2 ± 4.1 and 739 children were male. The median anti-HBs level was 23.0 mIU/mL, and the total percentage of anti-HBs levels ≥10 mIU/mL was 60.9%. With an increase of age, median anti-HBs level, percentage of anti-HBs levels ≥10 mIU/mL, and percentage of anti-HBs levels ≥100 mIU/mL declined remarkably in the early period and reached the lowest level at the age of 3 and then remained relatively stable. The median anti-HBs level, the percentage of anti-HBs levels ≥10 mIU/mL, and the percentage of anti-HBs levels ≥100 mIU/mL in 1- and 2-year-old children were much higher than that in children aged 3-15 (p < 0.05, respectively). Immunity against HBV infection gradually decreased in early ages of children of 15 and younger who received three doses of 5 μg hepatitis B vaccine series during infancy in China. Three dosages of 10 μg hepatitis B vaccine for infants and repeated vaccination or additional booster vaccination for some children at or before age 3 should be provided to get much more powerful immunity to HBV.

Discrepancy between serological and virological analysis of viral hepatitis in hemodialysis patients

BACKGROUND AND AIM

Viral hepatitis is a health threat for hemodialysis (HD) patients and it may be transmitted during treatment. Some patients categorized to have viral hepatitis were found to be non-viremic. To clarify the discrepancy between the serological tests in HD patients, we conducted the study.

METHODS

A total of 1681 HD patients was included. Blood samples were analyzed for hepatitis B surface antigen (HBsAg) and anti-hepatitis C antibody (anti-HCV). Detection of hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA were performed in either HBsAg (+) or anti-HCV (+) samples. HBV DNA/HCV RNA was also measured in a subset of HBsAg (-) and anti-HCV (-) patients. Liver function tests were analyzed and compared with the serological and virological tests.

RESULTS

The serological tests showed that 230 patients (13.7%) were HBsAg (+) and 290 (17.3%) were anti-HCV (+). We were unable to detect HBV DNA in 97 of 230 (42.2%) HBsAg (+) patients, and HCV RNA could not be found in 76 of 290 (26.2%) anti-HCV (+) patients. In 167 HBsAg (-) patients, only one showed a trace amount of HBV DNA. None of 151 anti-HCV (-) patients showed detectable HCV RNA. The prevalence rate of viral hepatitis remains high in Taiwanese HD patients: 13.7% for HBV and 17.3% for HCV. However, virological analysis showed 42.2% non-viremic rate for HBsAg and 26.2% non-viremic rate for anti-HCV.

CONCLUSIONS

The findings might challenge the presently suggested principles of bed and machine dedication and the diagnosis of viral hepatitis in HD patients.

The effects of telbivudine in late pregnancy to prevent intrauterine transmission of the hepatitis B virus: a systematic review and meta-analysis

Chronic hepatitis B virus (HBV) infection poses a serious public health problem in many parts of the world. Presently, even with proper joint immunoprophylaxis, approximately 10-15% of newborns from HBV carrier mothers suffer from HBV infection through intrauterine transmission. One of the risk factors is the level of maternal viraemia. Telbivudine is a synthetic thymidine nucleoside analogue with activity against HBV. A few studies have evaluated the efficacy of telbivudine in preventing intrauterine HBV infection during late pregnancy. So we conducted this meta-analysis to arrive at an evidence-based conclusion. We searched Medline/PubMed, EMBASE, Cochrane Library, Web of Knowledge and China Biological Medicine Database from January 1990 to December 2011. Relative risks (RR) of the seropositivity rates for hepatitis B surface antigen (HBsAg) and HBV DNA in newborns and infants were studied. Mean differences (MD) in maternal HBV DNA levels were reviewed. Finally two randomised controlled trials (RCTs) and four non-randomised controlled trials (NRCTs) were left for analysis which included 576 mothers in total, of whom 306 received telbivudine treatment and 270 did not receive any drug. All newborns received hepatitis B vaccine (HBVac) and hepatitis B immunoglobulin (HBIG) after birth. The seropositivity rate for HBsAg or HBV DNA was significantly lower in the telbivudine group, both at birth and at 6–12 months follow up. Meanwhile, maternal HBV DNA levels prior to delivery were significantly lower in the telbivudine group. In addition, the frequency of serum creatine kinase (CK) elevation was similar in the two groups. Our meta-analysis provides preliminary evidence that telbivudine application in late pregnancy is effective in the interruption of intrauterine HBV infection, with no significant adverse effects or complications. More high quality, well-designed, double-blinded, randomised controlled and large size clinical trials are needed for further investigation and more convincing results in the future.

Hepatitis B virus in transfusion medicine: still a problem?

Hepatitis B virus (HBV) has probably evolved with humans for nearly 35,000 years. HBV diversified into 9 genotypes (A-I) presenting specific features directing epidemiology, clinical expression and testing. Genotypes E and C are more infectious and carry higher risk of chronicity and cancer. HBsAg blood screening implemented 40 years ago enormously decreased the risk of transfusion transmission but the remaining risk requires extremely sensitive nucleic acid testing (NAT) to be removed. Limitations of the host immune system, the impact of immunodeficiency and the mechanisms utilised for viral persistence were recently identified. HBV replication produces excess HBsAg and infectious and defective viral particles but screening assays for HBsAg or viral particles alone do not allow fully efficient detection, making necessary screening for both. The host immune system fails to completely control the virus that escapes and persists unrecognized at very low levels or as immuno-selected variants. Variants may not be identified by assays, explaining false negative results. Specific mutations may affect post-transcriptional mechanisms including HBV RNA splicing. Asymptomatic HBV infected blood donors are at risk of long-term complications through mechanisms to be understood for appropriate counselling. Infectivity of occult HBV infection (OBI) by transfusion appears low, anti-HBc (anti-core antigen) only being more infectious than anti-HBs (anti-S protein) positive units.

Towards the eradication of hepatitis B in Taiwan

Viral hepatitides are important public health problems in humans. The etiologic agents were not identified until 1965, when Baruch S. Blumberg found the relationship of Australia antigen to serum hepatitis. The antigen was found to be the surface antigen of the hepatitis B virus (HBV). This observation launched a new era in the diagnosis, prevention and treatment of hepatitis B. Over 15-20 years, the natural history of HBV infection was elucidated, and more importantly, an effective vaccine became available. The routes of transmission were also made clear, rendering effective interruption of the transmission possible. The vaccine together with effective interruption of the transmission contributed greatly to the control of HBV infection. However, these measures do very little for those who have already been chronically infected. Fortunately, specific therapies against chronic hepatitis B started to appear about 10-15 years before, and the treatments have improved substantially in the last few years. Although far from perfect, effective means to treat those who are chronically infected now exist. In Taiwan, acute and chronic liver diseases were rampant as early as the beginning of the last century. Studies around 1975, showed an extremely high prevalence of chronic hepatitis B infection in the general population (15-20%), and 80-90% of the chronic liver diseases and hepatocellular carcinoma were caused by chronic infection with the HBV. This important health problem caught the attention of the government in the late 1970s, and a government-sponsored control program was finalized in 1981. Accordingly, a mass vaccination program against hepatitis B, primarily aiming at immunizing newborn infants, was launched on July 1, 1984. Twenty years after implementation of the program, the hepatitis B carrier rate in children covered by the program decreased by 85%, from ∼ 15% to <1%. Most importantly, the deadly sequela of hepatocellular carcinoma in the vaccinees was also found to decrease in parallel. This is the first time that a human cancer was prevented by vaccination. Despite the success, there are still some who were born after implementation of the program but were not prevented from developing chronic hepatitis B infection and hepatocellular carcinoma. Non-compliance to the vaccination schedule, breakthrough infection and intrauterine infection are the causes of the failure. At present, we have effective measures for immunizing susceptible individuals, interrupting the routes of transmission and treating the chronically infected. The time for considering the elimination or even the eradication of HBV infection has come. This is especially true for countries where hepatitis B infection is not endemic. Nevertheless, with the admirable results achieved in the past, Taiwan should also think about elimination/eradication of hepatitis B, even though it will certainly be much more difficult than in the non-endemic countries. In exploring the possibility of eliminating/eradicating hepatitis B in Taiwan, we reviewed the epidemiology of hepatitis B, and analyzed the problems that remain to be tackled in Taiwan. We hope that Taiwan can take further steps towards the elimination or eradication of hepatitis B.

Viral hepatitis infections in southern Taiwan: a multicenter community-based study

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are major causes of liver disease in Taiwan and have a great impact on the health of this country. This study investigated the seroprevalence of HBV and HCV in southern Taiwan. Screening programs were performed from September 1999 to August 2005 for community-based surveillance of liver disease. A total of 28,797 adults from southern Taiwan, including Kaohsiung City (n = 14,036), Kaohsiung County (n = 7,713), and Pingtung County (n = 7,048) were participated. The mean age was 50.3 ± 14.6 years (range, 20-97 years), with 41.0% were men. Hepatitis B surface antigen (HBsAg), antibody to HCV (anti-HCV), and liver function tests were performed. Among the 28,797 adults, the prevalence of HBsAg(+) was 15.1% and that for anti-HCV(+) was 8.6%. The seroprevalence of HBsAg in Kaohsiung County was 18.2%, which was higher than in Kaohsiung City (14.7%, p < 0.001) or Pingtung County (12.5%, p < 0.001). The seroprevalence of anti-HCV in Kaohsiung County was 17.2%, which was higher than in the other regions (Kaohsiung City = 5.8%, p < 0.001; Pingtung County = 4.6%, p < 0.001). The prevalence of dual HBsAg and anti-HCV was 1.1% (323 patients). Tzukuan Township in Kaohsiung County was endemic for HBsAg (19.1%, 1,026/5,375 patients), anti-HCV (22.4%, 1,203/5,375 patients), and dual HBsAg/anti-HCV (3.6%, 191/5,375 patients). Subjects with anti-HCV(+) were older and had higher alanine transaminase levels than their HBsAg(+) counterparts (p < 0.001 and p < 0.001, respectively). The current study shows the epidemiological characteristics of HBV and HCV infections among adults in southern Taiwan. Viral hepatitis infections remain widely endemic in this region.