Effect of selective vaccination on a decrease in the rate of hepatitis B virus-positive Japanese first-time blood donors

Workplace factors associated with willingness to undergo human immunodeficiency virus testing during workplace health checkups

BACKGROUND

To examine workplace factors associated with willingness to undergo human immunodeficiency virus (HIV) testing during workplace health checkups.

METHODS

This cross-sectional study used an Internet-based self-administered questionnaire to obtain data from a pool of 24,287 Japanese workers. Binary and multiple logistic regression analyses evaluated the association between workplace factors and HIV testing. Data were adjusted for sex, age, marital status, education, and history of HIV testing.

RESULTS

We gathered information from 4,143 (17.1%) respondents, of whom 1,129 (27.3%) were willing to be tested for HIV as part of a workplace health checkup. The participants were 20-59 years old. Approximately half of the participants were male (49.9%), half were married (48.9%), and half had completed higher education (47.6%). Workplace hepatitis testing was offered to 15.6% of the respondents, and most participants underwent health checkups without their colleagues (52.1%) at a medical facility (60.2%). Willingness to undergo HIV testing was positively correlated with having an increased risk of occupational blood exposure (vs. not at risk, adjusted odds ratio [OR]: 1.74, 95% confidence interval [CI]: 1.41-2.15) or working in medical and welfare roles (vs. manufacturing, OR: 1.40, 95% CI: 1.07-1.84). The presence of occupational health staff at the workplace (vs. their absence, adjusted OR: 1.35, 95% CI: 1.16-1.59) and hepatitis testing (vs. not testing, adjusted OR: 2.02, 95% CI: 1.66-2.44) increased willingness to undergo HIV testing.

CONCLUSIONS

A pilot HIV-testing program involving individuals at an increased risk of occupational blood exposure and undergoing hepatitis tests in workplaces providing occupational health staff support is recommended.

Progress and challenges for the Japanese immunization program: Beyond the "vaccine gap"

The Japanese immunization program has made considerable recent progress. The introduction of several new vaccines, especially foreign-produced vaccines, and the inclusion of important new vaccines in the National Immunization Program (NIP) are closing the "vaccine gap", i.e., the delay in the Japanese immunization program relative to programs in other developed countries. Major progress in the Japanese immunization program since 2014 includes (1) elimination of measles in March 2015, (2) introduction of a varicella vaccine as a routine immunization in the NIP in October 2015, and (3) introduction of hepatitis B virus vaccines as routine immunizations in the NIP in October 2016. Despite these promising developments, important issues remain. First, the government withdrew the active recommendation for human papilloma virus vaccines temporarily in 2013. The withdrawal has continued and unresolved despite new scientific evidence confirming the safety of these vaccines. Second, a few important voluntary vaccines, including vaccines for mumps and rotavirus, have not been included in the NIP since their introduction to Japan. Finally, there are concerns related to a shortage of mandatory domestic vaccines, which was caused by a natural disaster in the area where a vaccine-producing factory was located. Additionally, the manufacturer included unauthorized additives in some vaccine products with falsifying the production-process records. To avoid problems related to vaccine shortages, essential vaccines need to be stockpiled, and the future vaccine needs for children should to be discussed. New initiatives must continue to close the vaccine gap, as this will protect children living in Japan from vaccine-preventable diseases.

Virological and Clinical Characteristics of Hepatitis B Virus Genotype A

Hepatitis B virus (HBV) infection is one of the most prevalent chronic viral infections in humans. The overall prevalence of hepatitis B surface antigen (HBsAg) is reported to be 3.6%; however, it varies depending upon the geographic area. HBV is classified into ten genotypes (A through J) on the basis of an intergroup genomic divergence of > 8%. Specifically, HBV genotype A exhibits several unique virological and clinical characteristics and can be further classified into seven subtypes. Among them, subtype A2 or Ae (A2/[e]) is occasionally responsible for nosocomial infection and among homosexual males. Regarding virological factors, the G1896A precore mutation is rarely observed in genotype A as it would disrupt an essential stem-loop structure in the ε signal essential for pregenomic RNA packaging. HBV genotype A also harbors a 6-nucleotide C-terminal insertion in the hepatitis B-e antigen (HBeAg) precursor, resulting in a variable-length HBeAg protein product observed in serum of positive patients. These molecular traits likely contribute to the specific clinical presentation of genotype A-infected patients, such as mild acute hepatitis B (AHB), longer persistence of HBsAg positivity in AHB, and increased chronicity after AHB in adults. However, genotype A shows a better response to interferon than other genotypes in chronic hepatitis B patients. Here, we review the virological and clinical characteristics of HBV genotype A that will be useful in elucidating the association among persistent viral infection, host genetic factors, and treatment in future studies.

Seroepidemiological study of hepatitis B virus markers in Japan

BACKGROUND

In Japan, since 1986, selective vaccination has been implemented as a hepatitis B prevention strategy. The target of vaccination is the infant born to a hepatitis B surface antigen (HBsAg)-positive mother. The current Japanese hepatitis B prevention strategy focuses on reducing the number of HBV carriers but overlooks the risk to susceptible populations. We conducted a nationwide HBV seroepidemiological study to explore the next hepatitis B control strategy.

METHODS

We used sera derived from healthy individuals collected nationwide from 2005 through 2011 to investigate the HBsAg seroprevalence among children aged 4-9 years and 10-15 years (3000 samples) and hepatitis B core antibody (HBcAb) seroprevalence among people 10-39 years of age (600 samples).

FINDINGS

Among sera from 3000 children, 5 (0.17%) specimens were HBsAg-positive. There was no significant difference in HBsAg prevalence between age groups. Among 600 samples, 15 (2.5%) were HBcAb-positive. Out of 15 samples, 4 were from teenagers. Both HBsAg- and HBcAb-positive sera were found mainly in the Southern area of Japan.

CONCLUSION

The prevalence of HBsAg among children was 0.17% in the present study. This is higher than the prevalence reported in previous studies performed in the local area or in blood donors. The prevalence of HBcAb is also higher than we estimated. One of the reasons for this discrepancy from previous studies may be due to the small sample size and the impact of HBV high-endemic areas included in the present nationwide study. Nevertheless, our findings revealed that the opportunities for acquiring HBV infection in the susceptible population were more frequent than we thought, especially in some localities. Hepatitis B vaccination should be introduced into the routine child immunization program for susceptible populations, and the selective vaccination program should be continued for high-risk children.

Time trends of clinical characteristics in hepatocellular carcinoma patients with chronic hepatitis B virus infection: A field survey between 2000 and 2012

The hepatitis B virus (HBV) carrier rate has decreased in Japan; however, the incidence of HBV infection among hepatocellular carcinoma (HCC) patients has not decreased accordingly. In this study, we aimed to assess the time trends of the clinical characteristics in HCC patients with chronic HBV infection. Between 2000 and 2012, we enrolled a total of 156 HCC patients with chronic HBV infection in our field survey. The HCC risk was evaluated using the HCC prediction score, which is constructed from the characteristics of age, presence of liver cirrhosis and serum levels of albumin, bilirubin and HBV DNA. Lifestyle factors and the presence of diabetes mellitus were also evaluated. The time trends of patient characteristics were analyzed using the Jonckheere-Terpstra proportion trend test. Among HCC patients with chronic HBV infection, the proportion of patients at high risk according to the HCC prediction score significantly decreased during the study period (P=0.0005). Similarly, the proportion of patients with liver cirrhosis, ≤3.5 g/dl serum albumin level, >4 log copies/ml serum HBV DNA level and ≥60 g/day alcohol intake were also significantly decreased. The proportion of male and obese patients was not significantly altered, whereas the proportion of elderly (≥65 years) and diabetic patients tended to increase during the study period (P=0.0654 and P=0.0528, respectively). In this study, we analyzed the time trends of the clinical characteristics in HCC patients with chronic HBV infection and demonstrated that aging and diabetes mellitus may be involved in the hepatocarcinogenesis in patients with chronic HBV infection.

Molecular analysis of the interspousal transmission of hepatitis B virus in two Japanese patients who acquired fulminant hepatitis B after 50 and 49 years of marriage

A 71-year-old (C1I) and 69-year-old (C2I) Japanese female contracted fulminant hepatitis B after 50 and 49 years of marriage, respectively. Both index cases exhibited high levels of anti-HBc IgM antibodies (24.2 and 31.5 S/CO, respectively), suggestive of acute hepatitis B virus (HBV) infection, although they had no discernible risk factors for HBV infection, except for chronically HBV-infected spouses with detectable HBV DNA (3.3 log copies/ml [C1S: 72-year-old] and 7.2 log copies/ml [C2S: 71-year-old]). The HBV genotype/subgenotype was identical in each couple (B/B1 or C/C2). The HBV isolates from the index cases and spouses shared a nucleotide sequence identity of 99.5% and 99.7%, respectively, over the entire genome, and these four isolates had the highest nucleotide sequence identity of only 97% to HBV isolates deposited in DNA databases. Phylogenetic trees confirmed a close relationship of the HBV isolates between C1I and C1S and between C2I and C2S, supported by a high bootstrap value of 100% within each couple, indicating the transfer of HBV infection between spouses. These four isolates shared a precore mutation of G1896A known to be associated with fulminant hepatitis B. Although the history of sexual contact within a reasonable incubation period was obscure for one stable, monogamous couple (C1I and C1S), the other couple had a monogamous sexual relationship within six months prior to disease onset. This study indicates that two elderly Japanese patients with fulminant hepatitis B acquired HBV infection via interspousal (most likely sexual) transmission during long-lasting marriages.

Risk factors for long-term persistence of serum hepatitis B surface antigen following acute hepatitis B virus infection in Japanese adults

The proportion of patients who progress to chronicity following acute hepatitis B (AHB) varies widely worldwide. Moreover, the association between viral persistence after AHB and hepatitis B virus (HBV) genotypes in adults remains unclear. A nationwide multicenter study was conducted throughout Japan to evaluate the influence of clinical and virological factors on chronic outcomes in patients with AHB. For comparing factors between AHB patients with viral persistence and those with self-limited infection, 212 AHB patients without human immunodeficiency virus (HIV) coinfection were observed in 38 liver centers until serum hepatitis B surface antigen (HBsAg) disappeared or a minimum of 6 months in cases where HBsAg persisted. The time to disappearance of HBsAg was significantly longer for genotype A patients than that of patients infected with non-A genotypes. When chronicity was defined as the persistence of HBsAg positivity for more than 6 or 12 months, the rate of progression to chronicity was higher in patients with genotype A, although many cases caused by genotype A were prolonged cases of AHB, rather than chronic infection. Multivariate logistic regression analysis revealed only genotype A was independently associated with viral persistence following AHB. A higher peak level of HBV DNA and a lower peak of alanine aminotransferase (ALT) levels were characteristics of AHB caused by genotype A. Treatment with nucleotide analogs (NAs) did not prevent progression to chronic infection following AHB overall. Subanalysis suggested early NA initiation may enhance the viral clearance.

CONCLUSION

Genotype A was an independent risk factor for progression to chronic infection following AHB. Our data will be useful in elucidating the association between viral persistence after AHB, host genetic factors, and treatment with NAs in future studies.

Hepatitis screening in Japanese individuals of working age and prejudice against infected persons in the workplace

BACKGROUND

Laboratory confirmation of viral hepatitis infection represents an important issue for working age populations, as early detection and treatment can help ameliorate clinical progression of the disease. On the other hand, prejudice may occur in the workplace against those identified by a positive hepatitis test. This study investigated attitudes towards viral hepatitis testing in Japanese people of working age, including their desire to undergo such testing, and prejudice against persons infected with hepatitis virus.

METHODS

A total of 3,129 working age individuals were recruited from a company that conducts Internet surveys in Japan.

RESULTS

Of the respondents, 21.3% had previously undergone viral hepatitis testing, most frequently when it was an additional option during a health checkup or health screening for local residents (36.2%) and when it was included in regular health checkups in their workplace (19.2%). Among the respondents with no history of testing, 68.7% expressed a desire to undergo testing, of whom 74.8% wanted to have the test as part of their regular health checkups in the workplace. According to the respondents, if a coworker tested positive for hepatitis, 36.0% reported that they would be anxious about it, 32.0% would try to avoid contact with the infected person as long as circumstances permitted, and 23.7% said they might harbor some kind of bias.

CONCLUSIONS

Although further promotion of viral hepatitis testing is needed and this might be achieved during regular health checkups in Japanese workplaces, educational strategies will also be essential to help reduce bias against those who test positive.

Prevalence and epidemiological traits of HIV infections in populations with high-risk behaviours as revealed by genetic analysis of HBV

The prevalence and epidemiological traits of human immunodeficiency virus (HIV)/hepatitis B virus (HBV) infections in high-risk populations (HRPs) remained unclarified in Japan. We determined the prevalence of HIV, HBV and Treponema pallidum (TP) and the viral genotypes in HRPs who attended primary sexually transmitted infection (STI) clinics in Osaka province during 2006-2011. Of 7898 specimens, 133 (1·7%) were HIV positive, which was significantly higher than the figures reported by Japanese Red Cross (0·0019%) and public health centres (0·27%) in Japan. The frequency of HIV-1 subtype B was 88·7%, followed by CRF01_AE (2·3%) and C (0·8%), which were almost identical to the national trend. HBV seroprevalence was surprisingly high in the HIV-positive group (63·2%), which was significantly higher than that in the HIV-negative group (25·6%). By contrast, there was no statistical correlation between HIV and TP infection. Interestingly, the distinct HBV genotypes Ae and G were prevalent in the HIV-positive population (60·0% and 20·0%, respectively), although both were rarely detected during nationwide surveillance. The transmission of HIV and HBV appeared to occur largely within a closed community early in life. Of note, about one-quarter of HIV-positive cases would have remained untested if health professionals had not motivated individuals to undergo HIV testing. This is the first evidence-based assessment of HIV positivity and HIV/HBV co-infection in HRPs at primary STIs in Japan and the effect of the involvement of health professionals in the diagnosis of HIV infections in asymptomatic carriers. The genotyping of HBV provided valuable information for understanding HIV epidemical traits.

Reduction of hepatocellular carcinoma in childhood after introduction of selective vaccination against hepatitis B virus for infants born to HBV carrier mothers

OBJECTIVE

A nation-wide prevention program utilizing passive-active immunoprophylaxis for high-risk babies against maternal HBV transmission was introduced in Japan in January of 1986. The prevention program was expected to eradicate HBV-related hepatocellular carcinoma (HCC). The aim of this study was to evaluate the effect of this selective prevention program against maternal HBV transmission on the occurrence of HBV-related HCC.

METHODS

We reviewed the annual reports from a nation-wide survey of childhood solid tumors that was reported in the Journal of the Japanese Society of Pediatric Surgeons during the 28 years period from 1981 to 2008. The number of HCC cases were grouped for every 5-year period with an additional period of the past 3 years and compared with those of hepatoblastoma.

RESULTS

The reported number of children with hepatoblastoma in each period was constant during the 28 years study period. In contrast, both the number of patients with HBV-related HCC and the ratio of HBV-related HCC to hepatoblastoma gradually decreased over the study period, with a significant drop in the last two periods ranging from 2001 to 2008 (p < 0.001).

CONCLUSION

The prevention program against maternal HBV infection of infants born to HBV carrier mothers may have decreased the occurrence of HBV-related HCC in childhood.

Epidemiological survey of Japanese children infected with hepatitis B and C viruses

AIM

  The lack of a nationwide survey on hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in Japan led us to investigate the epidemiological profiles of these infections among Japanese children.

METHODS

  We conducted a questionnaire survey of children (<20 years of age) infected with either HBV (n = 136) or HCV (n = 114), who visited 636 pediatric institutions in Japan from 2003 through 2005. Most HBV-infected subjects (94%) were born in 1986 or after when a nationwide immunization program for infants born to HBe antigen-positive carriers was initiated. The transmission routes were divided into five groups: maternal, horizontal (subdivided into intrafamilial, iatrogenic and other horizontal), and unknown transmission.

RESULTS

  Comparison of subjects born in 1990 or after and those born in 1989 or before, when anti-HBc and anti-HCV (c100-3) screening tests of blood donors began, showed a shift in the relative proportions of maternal, intrafamilial, iatrogenic, other horizontal, and unknown transmission from 52%, 19%, 4%, 7% and 19% to 70%, 14%, 6%, 1% and 9%, respectively, for HBV, which was statistically insignificant (P = 0.120), and from 14%, 0%, 76%, 4% and 7% to 89%, 2%, 4%, 0% and 5%, respectively, for HCV, which was statistically significant (P < 0.001). HBV horizontal transmission did not decrease in proportion. No transfusion-acquired HCV infection was reported in subjects born in 1993 or after.

CONCLUSION

  Maternal transmission is a prominent source of HCV infection among Japanese children. The implementation of measures to prevent HBV horizontal infection is also essential, and the present system of selective vaccination should be expanded to universal vaccination.