(1983), two cases of anaphylaxis or collapse were reported during the primary series of DT immunizations (133,500 children; each child completed a course of three doses), six followed booster DT immunization (221,000 children; one dose), and one followed immunization with tetanus toxoid (the number immunized was not given). Five of these children were described as becoming cold, clammy, and pulseless, but all "recovered rapidly." The other four children were said to have mild manifestations, including slight facial swelling, pallor, and vasovagal attacks, from which they recovered. From the available descriptions, none of the events in either study resembled anaphylaxis as defined for the present analysis.

None.

None.

Studies in experimental animals and data collected from human subjects suggest that both tetanus and diphtheria toxoids can induce immediate hypersensitivity reactions. Although elevated levels of tetanus-and diphtheria-specific IgE antibodies are frequently demonstrated in immunized individuals, neither these antibodies nor immediate skin reactivity correlates well with clinical manifestations of hypersensitivity to the toxoids. Nine cases of anaphylaxis temporally related to immunization with tetanus toxoid alone have been reported since the removal of contaminating proteins. Thus, it appears that tetanus toxoid can cause anaphylaxis. No cases of anaphylaxis associated with administration of diphtheria toxoid alone have been reported.

The evidence establishes a causal relation between tetanus toxoid and anaphylaxis.

If the evidence establishes a causal relation between tetanus toxoid and anaphylaxis, then in the committee's judgment the evidence establishes a causal relation between DT or Td and anaphylaxis.

Because the conclusions are not based on controlled studies, no estimate of incidence or relative risk is available. It would seem to be low.