@article{oai:dmu.repo.nii.ac.jp:00001471,
 author = {Ishikawa, Yayoi and Ohyatsu, Mariko and Chibana, Yoko and Watanabe, Naomi and Ohrui, Masami},
 issue = {1},
 journal = {Dokkyo Journal of Medical Sciences},
 month = {Mar},
 note = {Background and Aim：The duration of protection afforded by Hepatitis B（HB）vaccination is unknown.　We aimed to investigate the antibody persistence and protection from hepatitis B virus infection in medical university students.

Methods：The subjects were the students of both medical and nursing students who had enrolled at　Dokkyo Medical University in April, 2012. We evaluated the HB vaccination results in 194 students （medical：100, nursing：94）who allowed us to observe during a 2-year follow-up. We measured antibody to HB surface antigen（anti-HBs）after completing one series of HB vaccinations, at 1 year and at 2 years.

Results：The anti-HBs positive（protective level ≥10 mIU/mL）rates of the students were shown after completing one series of HB vaccinations, at 1 year and at 2 years respectively. As follows：medical students；97.9％→80.6％→63.3％, nursing students；98.0％→84.8％→76.1％, and total students 97.9％
→82.6％→69.5％. The titers of the sustained anti-HBs positive students were significantly higher than the titers of the changed negative students of both medical and nursing students after completing HB vaccinations for 2 years（P＜0.001, respectively）.

Conclusions：Approximately 30％ of the students became anti-HBs seronegative during 2 years of follow-up. We should consider if it is necessary to administer additional vaccination for them to boost up thereafter.},
 pages = {1--7},
 title = {Changing Anti-HBs Levels after Hepatitis B Vaccination in Medical University Students：Results of a 2-Year Follow-up},
 volume = {44},
 year = {2017}
}