“After the fifth dose of DTaP, the odds of acquiring pertussis increased by an average of 42% per year,” the study’s authors write. Said another way, the overall protection rate of the DTaP vaccine declines to 71 percent from 95 percent by the fifth year after the fifth shot.

For context, unvaccinated children have odds of getting whooping cough “at least eight times higher than children who received all five doses” of DTaP (CDC pdf). Continue reading Whooping Cough Vaccine (DTaP) Not as Long-Lived as Thought