The Pertussis resurgence: putting together the pieces of the puzzle.

Christopher J. Gill,Rotem Lapidot

doi:10.1186/s40794-016-0043-8

Abstract

Pertussis incidence is rising in almost every country where acellular pertussis (aP) vaccines have been introduced, and is occurring across all age groups from infancy to adulthood. The key question is why? While several known factors such as waning of immunity, detection bias due to more sensitive tests and higher awareness of the disease among practitioners, and evolutionary shifts among B. pertussis all likely contribute, collectively, these do not adequately explain the existing epidemiologic data, suggesting that additional factors also contribute. Key amongst these is recent data indicating that the immune responses induced by aP vaccines differ fundamentally from those induced by the whole cell pertussis (wP) vaccines, and do not lead to mucosal immunity. If so, it appears likely that differences in how the two categories of vaccines work, may be pivotal to our overall understanding of the pertussis resurgence.

Highlights

Vaccines should possess two key attributes: 1) Direct protection of the vaccinee by creating endogenous immunity rendering him/her resistant to the disease in question; and 2) Indirect protection of individuals that were not vaccinated, by preventing circulation of the pathogen
Recent insights from mathematical models of pertussis transmission Probably one of the most significant finding from recent years is that acellular pertussis (aP) vaccines provide strong direct protection against severe disease, but may have relatively little indirect effect on transmission
Poor persistence, and leaky vaccine efficacy due to evolutionary shifts likely contribute to varying degrees in the pertussis resurgence, it seems far more likely that the key factor is instead immunologic

Summary

Introduction

Vaccines should possess two key attributes: 1) Direct protection of the vaccinee by creating endogenous immunity rendering him/her resistant to the disease in question; and 2) Indirect protection of individuals that were not vaccinated, by preventing circulation of the pathogen. While the vaccines clearly worked well, the specific immunological mechanisms that were essential to their effectiveness were never identified, nor the key antigens that induced these responses.

Results

Conclusion