Evolution of Bordetella pertussis under the influence of vaccination and its molecular-genetic properties

Abstract

In recent decades, there has been a global trend of increasing incidence of pertussis and changes in its epidemiological characteristics toward re-emergent properties. This trend has become especially pronounced in the post-COVID-19 pandemic period in the European Region (87,558 cases in 2023), including Ukraine (7,545 cases in 2024). One of the reasons for this situation is considered the introduction of the acellular pertussis vaccine (aP) in some countries, due to its shorter duration of post-vaccination immunity and the loss of certain antigens by circulating Bordetella pertussis strains under the pressure of specific post-vaccination antibodies. However, in Ukraine, the whole-cell pertussis vaccine (wP) is currently used for routine immunization. The aim of this work is to summarize scientific information on the biological properties of B. pertussis circulating in different regions and formed under the influence of aP and wP vaccines. The virulence factors of B. pertussis are analyzed, including those with antigenic properties used in aP vaccines. An analysis of existing scientific data on the molecular-genetic and antigenic characteristics of B. pertussis variants using aP and wP vaccines was carried out. It is concluded that long-term vaccination against pertussis, on the one hand, leads to a sharp decrease in the incidence of this infection, and on the other hand, contributes to the further evolution of B. pertussis, promoting changes or loss of certain antigens and further genetic distance from vaccine strains of both aP and wP types. This allowed the pathogen to evade specific immunity at both the individual and population levels and caused an increase in incidence. The aP vaccines accelerate such evolutionary changes to a greater extent. At the same time, the genetic diversity of variants in territories using aP vaccines is greater compared to those using wP (which may even be limited to clonal variants). A trend is observed toward increasing similarity of B. pertussis strains circulating worldwide.