Peer-reviewed article
Hepatitis B Virus Infection Status in Japanese Children Prior to Universal Vaccination: Sustained Effectiveness of Mother-to-Child Transmission Prevention and Residual Infection Burden.
Sakai A, Tanaka Y, Yotsuyanagi H, Sugiyama M, Morioka I et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study evaluated how well Japan's prevention of mother-to-child transmission (PMTCT) of hepatitis B worked over 25 years by testing nearly 17,000 children aged 0-15 years. The results show that PMTCT was very effective, with almost no children showing active hepatitis B infection. However, some children still showed signs of past exposure to the virus, suggesting that universal vaccination was needed to fully protect the population.
Key points
- Active HBsAg prevalence was extremely low: 0% in school-age children and 0.047% in hospital patients
- Most HBsAg-positive cases were found in children under 4 years old
- About 0.4-0.95% of children showed evidence of past HBV exposure (anti-HBc positive)
- Among those with past exposure, 10.3% had occult HBV infection detectable by DNA testing
- Antibody protection from vaccination declined with age, with only 1.9% of 15-year-olds showing detectable anti-HBs
Limitations
This study was conducted before universal vaccination started in 2016, so it cannot assess the long-term effectiveness of the vaccination program. The findings are specific to Japan and may not reflect other countries with different HBV epidemiology or prevention policies.
Abstract
Aim To evaluate the effectiveness of prevention of mother-to-child transmission (PMTCT) over 25 years, we conducted a nationwide epidemiological survey through a comprehensive assessment of hepatitis B virus (HBV) markers. Methods Two cohorts were recruited before universal vaccination: children aged 9-10 years undergoing school health checkups (Group 1) and hospital patients 0-15 years of age from 11 hospitals across Japan to assess age and regional differences (Group 2). Hepatitis B surface antigen (HBsAg) and core antibody (anti-HBc) were measured in both cohorts. HBV-DNA was tested to evaluate occult HBV infection and viral genotypes in Group 2. Anti-HBs antibody was measured to estimate HBV vaccine coverage. Results In Group 1 and Group 2, 8125 and 8453 samples were collected, respectively. HBsAg prevalence was 0% in Group 1 and 0.047% in Group 2 using a conventional assay (Lumipulse II HBsAg). Most HBsAg-positive samples were from children < 4 years. HBsAg-negative and anti-HBc-positive samples were detected in 0.42% of Group 1 and 0.95% of Group 2. Among these samples in Group 2, 10.3% were HBV-DNA-positive, indicating occult HBV infection. Genotype C predominated; however, four genotype D cases were identified in Hokkaido. Anti-HBs positivity among HBV-uninfected samples at ages 1, 2, 5, 10, and 15 years was 53.4%, 27.5%, 7.5%, 5.6%, and 1.9%, respectively. Conclusions Following the implementation of PMTCT measures in Japan, the prevalence of HBsAg-positive children was extremely low. However, the prevalence of occult infection and anti-HBc positivity indicated that some children remained exposed to HBV. To further eradicate HBV infection, universal vaccination was introduced nationwide in 2016.