Conflict of Interest Statement: SE has received consultancy fees and independent research grants from GlaxoSmithKline group of companies, Sanofi-Pasteur, Merck, Vifor, and DMG. MK was member of advisory boards for GSK, Pfizer, Baxter, Novartis, Astra Zeneca, MedImmune, SPMSD, Sanofi, MSD, Jansen, and performed for these companies presentations during industry symposia. These activities were done as a service task for his employer. Personally, he did not receive any fees from companies. There was also no target agreement with his employer in this respect. MO has received an investigator initiative research grant from Merck to evaluate population perception on hexavalent vs. heptavalent vaccines in Chile. KF is on the vaccine advisory boards for Sanofi Pasteur and Seqiris and have received honoraria from AstraZeneca and Pfizer for giving talks. PP has received research funding from the National Institute for Health Research and from GlaxoSmithKline, and has received honorariums from Sanofi Pasteur and Pfizer. CR has received consultancy fees and independent research grants from GlaxoSmithKline group of companies, Sanofi-Pasteur MSD, Wyeth, Pfizer, Astra-Zeneca, and Astellas.

Pertussis is an acute respiratory disease caused by Bordetella pertussis. Due to its frequency and severity, prevention of pertussis has been considered an important public health issue for many years. The development of the whole-cell pertussis vaccine (wPV) and its introduction into the pediatric immunization schedule was associated with a marked reduction in pertussis cases in the vaccinated cohort. However, due to the frequency of local and systemic adverse events after immunization with wPV, work on a less reactive vaccine was undertaken based on isolated B. pertussis components that induced protective immune responses with fewer local and systemic reactions. These component vaccines were termed acellular vaccines and contained one or more pertussis antigens, including pertussis toxin (PT), filamentous haemagglutinin (FHA), pertactin (PRN), and fimbrial proteins 2 (FIM2) and 3 (FIM3). Preparations containing up to five components were developed, and several efficacy trials clearly demonstrated that the aPVs were able to confer comparable short-term protection than the most effective wPVs with fewer local and systemic reactions. There has been a resurgence of pertussis observed in recent years. This paper reports the results of a Consensus Conference organized by the World Association for Infectious Disease and Immunological Disorders (WAidid) on June 22, 2018, in Perugia, Italy, with the goal of evaluating the most important reasons for the pertussis resurgence and the role of different aPVs in this resurgence.