HBワクチン接種者における獲得抗体価の推移 Investigation on Change of Acquired Antibodies in Responders against Hepatitis B Vaccine
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HBワクチンの接種により獲得されたHBs抗体の抗体価の推移を, 長期経過後に抗体価を再測定し検討を行った. 著者らの病院の教職員に集団接種クールとして, 組換えHBワクチン10μgを3回筋肉内に接種した. 接種クール完了4週後にRIA法にて測定した抗体価が, cut off index (C. I.) 2.0以上に陽転した者は185名であった. このうち, クール完了38カ月後に, 完了4週後の抗体価測定以後初めて再測定を行った者, 48名を検討対象とした. 4週後にはC. I. 50以上の高反応者は7名, 10～49の中反応者は29名, 9.9以下の低反応者は12名であったが, 38カ月後には4週後の抗体価に比例して低下がみられ, 各々0名, 4名, 22名となり, 1.9以下への再陰転化が22名にみられた. 感染予防に十分な抗体価を10以上とすると, 38カ月後に36名中32名が10未満に, また, 完了16カ月後にHBs抗体価を初測定し得た群では, 16カ月後に24名中8名が10未満になり, 追加接種が必要であった. 38カ月後に10未満に低下していた32名のうち12名に, HBワクチンを1回追加接種した結果, 全員が再び10以上となり, 平均抗体価でもクール完了後の価を上回り, 良好な反応が得られた. 以上, ワクチンにより獲得されたHBs抗体価は急速に低下する傾向がみられるので, 感染予防に十分な抗体を保持するためには, 積極的に抗体価の再測定を行い, 追加接種を行う必要がある.
Changes of titers of acquired hepatitis B surface (HBs) antibodies against HB vaccine were investigated by measuring them again after a long lapse of time. Ten jig of the recombinant HB vaccine was intramuscularly injected respectively to the staff of the authors' hospital three times. Four weeks after a full course of the vaccination 185 persons could acquire antibodies, whose titers were 2.0 or more in cut off index (C. I.) by radioimmunoassay (RIA). Of these members titers of antibodies of 48 subjects could be remeasured for the first time 38 months after the meaurement of the titers in the 4th week after a full course of the vaccination. Four weeks after the last vaccination 7 persons were high responders whose titers of antibodies were 50 or more in C. I., 29 were medium responders with their titers from 49 to 10, and 12 were low responders having titers of less than 10. However, 38 months after the course the titers of those responders decreased so much that nobody remained highly responders, 22 were low responders, and the remaining 22 turned to be negative again with titers less than 2.0. Supposing that the titer of antibody enough to protect the infection of HB virus is 10 or more in C. I., 32 of 36 persons neededbooster shots 38 months later because their titers dwindled down to less than 10. While in 24 members, who had their titers of antibodies measured for the first time 16 months after the measurement of the titers in the 4th week after a full course of the vaccination, 8 members had titers which changed to be less than 10. Twelve of the 32 subjects, whose titers were less than 10 38 months later, recieved a booster injection, respectively. As a result, they obtained good responses; that is, all their titers returned to 10 or more, and the average titere was more than that 4 weeks after the planned course of the vaccination. It was confirmed that the titer of an acquired antibody should be measured repeatedly, and a booster shot is indispensable to keep the antibody high enough to protect from the infection, for the acquired HBs antibody has a tendency to reduce rapidly.
- Kansenshogaku Zasshi
Kansenshogaku Zasshi 69(2), 164-169, 1995
The Japanese Association for Infectious Diseases