Immunization Against Diphtheria in Japan

Introduction 2. Schedule of immunization 3. Diphtheria toxoid 4. Program of surveillance on the immune status against diphtheria 5. Immune status of children 6. Epidemiological feature of diphtheria 7. Discussion DIPHTHERIA IMMUNIZATION 331TABLE II Some characteristics of diphtheria toxoid preparations (1) Amount of diphtheria toxoid (Lf/ml)* * Figures show the results of titration at the NIH .** Some products produced before April , 1959 contained 80-90 Lf/ml.(2) Purity of the bulk toxoid (prescribed in 1971) : no less than 1,500 Lf and 2,500 Lf per mg protein nitrogen, for the usual toxoids and for that for adult use, respectively.(3) Aluminum content: (i) no higher than 10 mg per ml as alum by Min Req of 1952; 2 mg A 1 per ml by that of 1959; 1 mg A 1 per ml by that of 1971 .Most preparations available now contain 0.3-0.5 mg Al per ml.(ii) for Adsorbed Toxoid for adult use (1971) : no higher than 0.5 mg Al per ml.(4) Test for the reversal of toxicity: see Addendum 1.(5) Potency : see Addendum 1.