Adverse reactions to the preschool (fifth) dose of adsorbed diphtheria-pertussis-tetanus vaccine in Canadian children.
OBJECTIVE
To quantify accurately the rate of adverse reactions after the preschool (fifth) dose of adsorbed diphtheria toxoid-pertussis vaccine-tetanus toxoid (DPT) vaccine and to test the hypothesis that large local reactions are attributable to the diphtheria toxoid.


METHODS
Double-blind randomized controlled trial.


METHODS
Suburban community public health unit.


METHODS
Healthy children 4 to 5 years of age with a history of having received four doses of adsorbed DPT vaccine.


METHODS
Subjects were given either the standard DPT vaccine (with 25 Lf units of diphtheria toxoid) or a modified DPT vaccine (with 10 Lf units of diphtheria toxoid). They were assessed 24 hours later by a nurse. Serum samples obtained before vaccination were tested for diphtheria and tetanus antitoxin levels by means of neutralization assay and enzyme-linked immunosorbent assay.


METHODS
Rates of large local reactions (an area of redness or swelling or both of 5 cm or greater) 24 hours after vaccination in the two groups. Relation between serum antitoxin levels before vaccination and the rate of large local reactions in each group.


RESULTS
Of the 250 subjects enrolled 124 received the standard vaccine and 126 the modified one. Large local reactions occurred in 71% of the subjects receiving the standard vaccine and 52% of those receiving the modified one (p less than 0.01). In the former group large erythematous reactions occurred significantly more often in those with an elevated prevaccination diphtheria antitoxin level than in those without an elevated level; no relation was found between such reactions and the prevaccination tetanus antitoxin level. Reduced arm movement was evident in 45% of the children in the two groups. Few had systemic adverse reactions.


CONCLUSIONS
Large local reactions occur frequently after the preschool administration of the DPT vaccine. These reactions are uncomfortable but not serious. They result in part from the large amount of diphtheria toxoid in the standard DPT vaccine.
Scheifele
D W
DW
Vaccine Evaluation Center, British Columbia's Children's Hospital, Vancouver.
Meekison
W
W
Grace
M
M
Barreto
L
L
Carter
A O
AO
Mitchell
L
L
Farley
J
J
D002675:Child, Preschool; D004166:Diphtheria Antitoxin / Q000097:blood; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000009:adverse effects*; D004311:Double-Blind Method; D004890:Erythema / Q000209:etiology*; D005260:Female; D006801:Humans; D007158:Immunologic Techniques; D008297:Male; D013743:Tetanus Antitoxin / Q000097:blood
D004166:Diphtheria Antitoxin; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D013743:Tetanus Antitoxin