Determining Factors for Pertussis Vaccination Policy: A Study in Five EU Countries

Abstract

Pertussis vaccination policy varies across Europe, not only in the type of vaccine—whole cell (wP) vs. acellular (aP1/2/3/5)—but also in the schedule and recommendation for parents. This study aims to investigate the determining factors for the type of vaccine, immunization schedule and maternal immunization recommendation. From March to May 2019, experts in national health agencies and major academic or research institutions from Denmark, France, Poland, Sweden and the UK were invited to a semi-structured interview. Thematic analysis was performed on the transcripts using a codebook formulated by three coders. Inter-coder agreement was assessed. Fifteen expert interviews were conducted. The identified driving factors for pertussis vaccine policy were classified into three domains: scientific factors, sociological factors, and pragmatic factors. The determining factors for the type of vaccine were prescriber’s preference, concern of adverse events following immunization (AEFI), effectiveness, and consideration of other vaccine components in combined vaccines. The determining factors for infant schedule were immunity response and the potential to improve coverage and timeliness. The determining factors for maternal immunization were infant mortality and public acceptability. To conclude, socio-political and pragmatic factors were, besides scientific factors, important in determining the pertussis vaccine type, schedule of childhood immunization and recommendations for parents.

Global spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis

“…It remains unclear if this persistence is due to spatial heterogeneity in population immunity profiles (for example, from heterogeneous vaccine coverage) that can facilitate ongoing circulation of globally less fit strains, the external introduction of strains from environments where they have greater fitness, or unmeasured markers of fitness not captured by our approach. For example, whereas this study assesses the impact of vaccine type (WCV or ACV) on strain fitness, increased, sustained sequencing efforts would allow us to tackle more precise questions about whether different WCV or ACV vaccines (37)(38)(39) or vaccination policies and schedules (40,41) exert distinct pressures. Last, there may also be other mutations that are linked to changes in fitness that we have not considered (17).…”

Spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis

“…In the event of future switches from WCV to ACV, we could expect PRN-deficient strains to prevail, either through the successful introduction of strains circulating elsewhere or through the loss of PRN expressions in local strains. While this study assesses the impact of vaccine type (WCV or ACV) on strain fitness, increased, sustained sequencing efforts would allow us to tackle more precise questions about whether different WCV or ACV vaccines [33][34][35] or vaccination policies and schedules 36,37 exert distinct pressures. Finally, there may also be other mutations that are linked to changes in fitness that we have not considered here 17 .…”

Krztusiec I „Efekt Czerwonej Królowej”

“…Uważa się, że możliwe odczyny poszczepienne pojawiające się po zaszczepieniu szczepionką DTwP były głównym czynnikiem, który zadecydował o zmianie szczepionki pełnokomórkowej na bezkomórkową w programach szczepień wielu krajów [93]. Najnowsze analizy wskazują na wiele innych czynników, które miały zasadniczy wpływ na podjęcie decyzji o tej zmianie.…”