Waning protection after fifth dose of acellular pertussis vaccine in children

Abstract (PubMed)

In the United States, children receive five doses of diphtheria, tetanus, and acellular pertussis (DTaP) vaccine before age 7. A case-control study in Kaiser Permanente Northern California (2006-2011) compared 277 pertussis cases confirmed by PCR with PCR-negative controls and matched population controls. After the fifth dose of DTaP, the odds of acquiring pertussis increased by an average of 42% per year, demonstrating significant waning of vaccine-induced immunity over five years post-vaccination.