[Further improvements in schedules for immunizing children against diphtheria and tetanus].

The study of the rational schedule of revaccinations made at different ages for the prevention of diphtheria and tetanus was carried out on 800 children belonging to the age groups of 6-9 years and 11-14 years. The content of diphtheria antitoxin was determined by Jensen's method, and the content of tetanus antitoxin in the passive hemagglutination test. In the first age group immunity to the above-mentioned infections was determined after the primary immunization, and in the second age group after the first revaccination made at an age indicated in the schedule. The high level of immunity to both diphtheria and tetanus was shown to preserve for 6-7 years. For this reason intervals between revaccinations scheduled for children achieving a definite age in accordance with the existing scheme of immunization against diphtheria and tetanus may be increased. the most rational time for such revaccinations is the age of 9 (instead of 6) years and 16 (instead of 11) years.