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Hypotonic-hyporesponsive Episodes After Diphtheria, Tetanus and Acellular Pertussis Vaccination
John Hansen1, Michael D Decker2, Edwin Lewis1
1From the Kaiser Permanente Vaccine Study Center, Oakland, California.
Background:
Hypotonic-hyporesponsive episode (HHE) after whole cell pertussis vaccination is a known adverse event. Less is known about the risk of HHE after administration of acellular pertussis vaccines.
Methods:
Using parental interviews, this study actively surveyed for HHE among infants after doses 1 and 2 of acellular pertussis vaccine.
Results:
We interviewed the parents of 52,531 infants. HHE was reported at a rate of 22.8 per 100,000 doses (95% CI: 11.8-39.9) of acellular pertussis vaccine, approximately 45 episodes per 100,000 children.
Conclusions:
These rates are lower than HHE rates reported after whole cell pertussis vaccines and within the range of HHE rates reported in other studies of acellular pertussis vaccines.
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