Did you know that the effectiveness of the pertussis vaccine decreases rapidly after 4 years?
"Compared to unvaccinated participants, adjusted vaccine efficacy estimates for participants with updated vaccination ... were 80% ... 15-364 days, 84% ... 1-3 years, of the 62% ... 4-7 years and 41% ... 8 years or more after the last vaccination ... we observed waning immunity with the acellular vaccine, with an OR adjusted for pertussis infection 1,27 ... per year since the last vaccination. The priming of the acellular vaccine, compared to the whole cell vaccine, was associated with an increased probability of pertussis (adjusted OR 2,15) ... we observed a 'high early efficacy of the pertussis vaccine which rapidly declined when the time elapsed since the last vaccination exceeded 4 years, particularly with the priming of the acellular vaccine ".