Significance and anamnestic response in isolated hepatitis BÂ core antibody-positive individuals 18 years after neonatal hepatitis B virus vaccination in Taiwan

► Prevalence of isolated anti-HBc decreased after commencement of HBV vaccination. ► No evidence of occult HBV infection is observed in our isolated anti-HBc subjects. ► The presence of isolated anti-HBc 18 years after HBV vaccination can be attributed to post-HBV infection with a loss of anti-HBs and to a false positive anti-HBc result. ► The HBV status of the false-positive isolated anti-HBc was HBV naïve due to the waning-off effect of anti-HBs of the neonatal HBV vaccination. ► A single HBV booster dose of vaccine is recommended for subjects with isolated anti-HBc who were fully vaccinated with HBV vaccine.