Countermeasures against viral hepatitis B and C in Japan: An epidemiological point of view

Analysis of antibody-negative medical students after hepatitis B vaccination in Japan

Hepatitis B virus (HBV) vaccination is recommended for health-care professionals because of their frequent contact with blood. At one medical school, new students undergo HBV antibody tests upon admission, and antibody-negative individuals receive the HBV vaccine. We aimed to characterize individuals who remained antibody negative after HBV vaccination. Between 2009 and 2017, we enrolled 1064 first-year students from a medical school where their HBV antibody test and vaccination records remained. We analyzed data regarding the hepatitis B surface antibody (anti-HBs) test record during admission, vaccination record for antibody-negative participants, anti-HBs test result after completing the three vaccination doses, drug name of the vaccine used, sex, body mass index (BMI), and age. We calculated the yearly percentage of antibody-negative individuals and analyzed the characteristics of vaccine-refractory cases by logistic regression analysis. Of the 1064 participants, 999 were initially antibody negative. They were vaccinated with HBV thrice and tested for antibodies after vaccination. The average age of participants was 20.1 y, with 677 males. Although the type of vaccine has been changed since 2016, the average rate of refractoriness from 2009 to 2015 was 6.9% per year and 18.6% after 2016. Logistic regression analyses showed that sex (male vs. female; OR, 1.787), BMI (OR. 1.171), and vaccine type (genotype A vs. genotype C: OR, 3.144) were significant factors associated with antibody-negative individuals. Vaccine type differences altered the proportion of antibody-refractory individuals, with no association with age. The data on vaccine refractoriness will be continuously analyzed in the future while considering other factors.

A nationwide cross-sectional survey on hepatitis B and C screening among workers in Japan

In Japan, there is no publicly funded screening for hepatitis B virus (HBV) and hepatitis C virus (HCV) infections (using HBs antigen and HCV antibody, respectively) among workers, and workplace health programmes play a crucial role in reducing viral hepatitis-related deaths. The national number of hepatitis screening tests conducted in the workplace is unknown. To provide baseline data for policy formulation, we conducted a nationwide survey to estimate these parameters using data from approximately 10.5 million workers (6.8 million men and 3.8 million women) who underwent mandatory health examinations in their workplaces between April 2016 and March 2017. Among these workers, 494,303 (5.23%, 95% confidence interval [CI] 5.22%-5.24%) and 313, 193 (3.82%, 95% CI 3.81%-3.84%) were screened for HBV and HCV, respectively. Among those who were screened, 0.28% (95% CI 0.27-0.30%) and 0.35% (95% CI 0.33-0.37%) tested positive for HBs antigen and HCV antibody, respectively. According to the age-specific prevalence from the survey an estimated 0.30 and 0.14 million workers in Japan require treatment for HBV and HCV, respectively. To reduce viral hepatitis-related deaths by efficiently identifying workers who need treatment and promoting access to treatment, one-time hepatitis screening of all workers should be considered.

What is the Role of the Horizontal Transmission of Hepatitis B Virus Infection in Young Adult and Middle-Aged Roma Population Living in the Settlements in East Slovakia?

Background: The aim of our work is to objectify the manner of transmission of HBV infection in young adult and middle-aged Roma people who live in the settlements. Methods: We used data from the cross-sectional study HepaMeta. We analyzed Roma people living in the settlements in East Slovakia, who have had HBsAg and anti HBc IgG antibodies examined. Results: We analyzed a cohort of 452 Roma participants with a mean of age 34.67 ± 9.14 years—159 (35.2%) were males. HBsAg positivity was diagnosed in 12.4% and the presence of anti HBc IgG antibodies was confirmed in 52% of participants. Prevalence of HBsAg positivity increases significantly with higher age, (p = 0.026), as well as the presence of anti HBc IgG antibodies (p < 0.0001). The prevalence of HBsAg positivity has doubled and anti HBc IgG positivity has tripled within two decades (<25 years vs. 35–45 years) in Roma settlements in East Slovakia. Conclusions: These findings allow us to express an opinion that horizontal transmission in adulthood may play an important role in the spreading of HBV infection.