Data from: Pertussis immunity and epidemiology: mode and duration of vaccine-induced immunity

The resurgence of pertussis in some countries that maintain high
vaccination coverage has drawn attention to gaps in our understanding of
the epidemiological effects of pertussis vaccines. In particular, major
questions surround the nature, degree and durability of vaccine
protection. To address these questions, we used mechanistic transmission
models to examine regional time series incidence data from Italy in the
period immediately following the introduction of acellular pertussis (aP)
vaccine. Our results concur with recent animal-challenge experiments
wherein infections in aP-vaccinated individuals proved as transmissible as
those in naive individuals but much less symptomatic. On the other hand,
the data provide evidence for vaccine-driven reduction in susceptibility,
which we quantify via a synthetic measure of vaccine impact. As to the
precise nature of vaccine failure, the data do not allow us to distinguish
between leakiness and waning of vaccine immunity, or some combination of
these. Across the range of well-supported models, the nature and duration
of vaccine protection, the age profile of incidence and the range of
projected epidemiological futures differ substantially, underscoring the
importance of the remaining unknowns. We identify key data gaps: sources
of data that can supply the information needed to eliminate these
remaining uncertainties.