| HB universal vaccination program has started in Japan since 2016. However, 5-10% of people who received HBsAg-containing vaccines cannot produce anti-HBs antibody. Further, anti-HBs titer gradually decline over time even in HB vaccine responders. Thus, those people remain at a risk of HBV infection. We have developed a nasal administrative therapeutic vaccine, containing both HBsAg and HBcAg with carboxyl vinyl polymer. In this clinical trial , we aimed to assess the prophylactic efficacy of the new HB vaccine in non-responders and responders with low anti-HBs titers. Twenty-one non-responders (NR, anti-HBs<10mIU/mL with past HB vaccination) and 22 responders with low anti-HBs titer (LR, 10<anti-HBs<100mIU/mL) were enrolled. The vaccine was administered through nose three times every two weeks. Anti-HBs was measured 1 and 6 months (mo) after the last administration. In NR, anti-HBs turned positive in 90.5% (19/21) at 1mo, and in 85.7% (18/21) at 6mo. Anti-HBs titers increased from 0mIU/mL (0-3.7, baseline) to 679mIU/mL (167-1440, 1mo) and 262mIU/mL (28.5-738, 6mo). In LR, anti-HBs titers increased from 29.0mIU/mL (17.5-50.1, baseline) to 564 mIU/mL (2673-8948, 1mo) and 2485mIU/mL (878-5078, 6mo). The new HB vaccine administered nasally could be an effective prophylactic vaccine for non-responders, and useful tool for responders with low anti-HBs titer for boosting anti-HBs. |
