Fatal infection with Aeromonas sobria and Plesiomonas shigelloides.

525 vaccine. The vaccine contained formaldehyde detoxified, aluminium adsorbed diphtheria and tetanus toxins, 25 and 75 flocculation units/ml respectively (SBL, Sweden). The subjects were randomised by using sealed envelopes to receive the vaccine subcutaneously (21 subjects) or intracutaneously (18). The mean age was 29-8 (range 23-43) years, with no difference between the groups. Seven of the eight women were randomised to receive the vaccine subcutaneously. Before vaccination all subjects were Schick tested using standardised reagents (SBL, Sweden). After four days the reactions to the toxin and a heat inactivated control were determined. Induration with a diameter of .10 mm at the site of application of the Schick reagent and at least 500/o smaller reactions to the control reagent were considered to indicate lack of immunity. Reactions with a diameter < 10 mm were interpreted as indicating immunity, and reactions with a diameter >10 mm but no appreciable difference between the reagents were interpreted as pseudoreactions-that is, indicating possible hypersensi-tivity to an agent in the vaccine. Serum samples were collected from all subjects before and four weeks after vaccination and analysed for antibodies to diphtheria toxin using a microcell culture technique.2 Each sample was tested in fourfold dilution from 1:4 to 1:4096, corresponding to antitoxin titres, if positive, from 0-0025 to 2-56 IU. Subjects with titres-0-0025 IU were considered to be non-immune, those with titres between 0-001 and 0-004 IU to be partially immune, and those with titres >0-04 IU to be immune. Correlation between results of Schick test and diphtheria antitoxin tites and side effects to diphtheria and tetanus toxoids (figures are numbers ofsubjects who provided information) Result of Schick test Immunity No immunity Pseudoreaction Antitoxin titres Antitoxin titres before vaccination (IU): 500025 5 1 1 0-01-0-04 8 3 >0 04 10 1 8 Reactions to vaccine Erythema (mm): None 6 3 <20 7 1 1 20-50 7 1 7 <50 3 Induration (mm): None 4 1 50 2 7 Body temperature ('C): There was little correlation between serological results before vaccination and the reactions to the Schick test (table). Only one of seven subjects thought to be non-immune serologically had, a corresponding Schick reaction. A better correlation was seen among subjects who were serologically immune. The specificity of the Schick test was only 54% when falsely positive and negative reactions and pseudoreactions were excluded. The sensitivity was also low (69%) as 11 …