Short-lived immunity against pertussis, age-specific routes of transmission

Pertussis incidence has been increasing for the past two decades in Norway, as in much of the highly vaccinated world. The greatest increase is in teenagers, although the most severe cases occur in infants. A teenage booster is recommended globally, largely with the aim of reducing infant incidence. However few countries have implemented the booster, and almost no data have been published on its utility in preventing infant cases. This study aims to assess the duration of vaccine-induced immunity, and the possibility for a teenage-booster vaccine to protect infants in Norway.