

Pertussis is a globally endemic and highly infectious disease that can cause respiratory, nutritional and neurological complications, and death \[[@B1-vaccines-07-00065]\]. Infants and young children have the highest risk of pertussis sequelae and death during the window of vulnerability (between birth and the first infant pertussis vaccination) \[[@B2-vaccines-07-00065]\]. Since the introduction of whole-cell pertussis vaccines (wP) in the 1940s, global pertussis-related morbidity and mortality have decreased substantially, particularly in high-income countries \[[@B3-vaccines-07-00065]\]. However, despite vaccination, an estimated 16 million pertussis cases and 195,000 child deaths occur globally every year, with the greatest burden in low and middle-income countries \[[@B4-vaccines-07-00065]\]. Furthermore, many high-income countries with high and stable vaccination rates, such as New Zealand, Australia and the United States, have increasing pertussis burden and regular epidemics are not being prevented \[[@B1-vaccines-07-00065]\].

Acellular pertussis vaccines (aP) are now used instead of wP vaccines in most high-income countries. In comparison to wP vaccines, aP vaccines are less reactogenic, yet have a lower effectiveness \[[@B5-vaccines-07-00065],[@B6-vaccines-07-00065],[@B7-vaccines-07-00065],[@B8-vaccines-07-00065]\]. Estimates of aP vaccine effectiveness (VE) vary substantially with age, number of doses, outcome (hospitalisation/non-hospitalised notification/all cases), local epidemiology and health care service policies. For example, a New Zealand nested case-control study estimated a 93% VE against pertussis hospitalisation in the first year of life for a three-dose primary pertussis vaccination series (DTaP, Infanrix^®^-Hexa, GlaxoSmithKline, Rixensart, Belgium) \[[@B9-vaccines-07-00065]\]. However, an Australian case-control study estimated 85% VE against pertussis hospitalisation in the first year of life for a three-dose primary pertussis vaccination series (DTaP combination vaccines, GlaxoSmit