Estimated effects of a delay in the recommended vaccination schedule for diphtheria and tetanus toxoids and pertussis vaccine
A. W. Funkhouser, S. G. Wassilak, W. A. Orenstein, A. R. Hinman and E. A. Mortimer Jr
The occurrence of adverse events temporally associated with diphtheria and
tetanus toxoids and pertussis vaccine (DTP) has led to consideration of a
delay in the schedule of initial vaccination. We developed an inferential
model estimating the changes in pertussis- and DTP-associated health
outcomes that might occur if initial DTP administration were delayed from
2, 4, and 6 months to 8, 10, and 12 months of age. An additional 636 cases
of pertussis--115 of which would be associated with complications,
including two encephalopathies--were projected to occur under the proposed
as compared to the current schedule. Adverse medical events attributable to
the vaccine were assumed to remain unchanged following the change in
schedule. We projected 353 fewer chance associations with sudden infant
death syndrome but 1311 more chance associations between DTP and seizures.
These estimates suggest that the current schedule of vaccinating infants at
2, 4, and 6 months of age is casually associated with less morbidity and
should be continued.