• Counterattacking the tick bite: towards a rational design of anti-tick vaccines targeting pathogen transmission.

      Rego, Ryan O M; Trentelman, Jos J A; Anguita, Juan; Nijhof, Ard M; Sprong, Hein; Klempa, Boris; Hajdusek, Ondrej; Tomás-Cortázar, Julen; Azagi, Tal; Strnad, Martin; et al. (2019-05-14)
    • Effect of latent cytomegalovirus infection on the antibody response to influenza vaccination: a systematic review and meta-analysis.

      van den Berg, S P H; Warmink, K; Borghans, J A M; Knol, M J; van Baarle, D (2019-04-04)
      Latent infection with cytomegalovirus (CMV) is thought to accelerate aging of the immune system. With age, influenza vaccine responses are impaired. Although several studies investigated the effect of CMV infection on antibody responses to influenza vaccination, this led to contradicting conclusions. Therefore, we investigated the relation between CMV infection and the antibody response to influenza vaccination by performing a systematic review and meta-analysis. All studies on the antibody response to influenza vaccination in association with CMV infection were included (n = 17). The following outcome variables were extracted: (a) the geometric mean titer pre-/post-vaccination ratio (GMR) per CMV serostatus group, and in addition (b) the percentage of subjects with a response per CMV serostatus group and (c) the association between influenza- and CMV-specific antibody titers. The influenza-specific GMR revealed no clear evidence for an effect of CMV seropositivity on the influenza vaccine response in young or old individuals. Meta-analysis of the response rate to influenza vaccination showed a non-significant trend towards a negative effect of CMV seropositivity. However, funnel plot analysis suggests that this is a consequence of publication bias. A weak negative association between CMV antibody titers and influenza antibody titers was reported in several studies, but associations could not be analyzed systematically due to the variety of outcome variables. In conclusion, by systematically integrating the available studies, we show that there is no unequivocal evidence that latent CMV infection affects the influenza antibody response to vaccination. Further studies, including the level of CMV antibodies, are required to settle on the potential influence of latent CMV infection on the influenza vaccine response.
    • Persistence of immune response following bivalent HPV vaccination: A follow-up study among girls routinely vaccinated with a two-dose schedule.

      Schurink-van 't Klooster, Tessa M; Donken, Robine; Schepp, Rutger M; van der Klis, Fiona R M; de Melker, Hester E (2018-11-26)
      In this cohort study, we examined antibody levels and avidity after a two-dose schedule (0, 6 months) of the bivalent HPV-vaccine in girls routinely vaccinated in the Dutch HPV-vaccination program, up to 2 years following vaccination. A blood sample at 7, 12 and 24 months after the first dose and questionnaire data were collected (n = 56). HPV type-specific antibody concentrations (lU/ml) against seven types (HPV16/18/31/33/45/52/58) were assessed using a validated virus-like particles (VLP) multiplex immunoassay. Avidity was tested using a modification of this assay. Seropositivity for vaccine types HPV 16 and 18 was 100% up to month 24, but declined for HPV-types 31/33/45/52/58, although not statistically significant for HPV45. All Geometric Mean Concentrations (GMCs) declined by months 12 and 24, but remained high for HPV16/18. Between month 7 and 12, GMCs declined more for other types. High avidity antibodies were induced up to 24 months for vaccine types (75%, 76-78% and 81-82% at months 7, 12 and 24, respectively), but for other types antibody avidity was 16-29% at month 7, 20-32% at month 12 and 19-32% at month 24. GMCs declined over time for HPV-types 16/18/31/33/45/52/58, but remained high for vaccine-types HPV16/18 up to 24 months of follow-up. Antibody avidity was >75% for vaccine types but <35% for other HPV-types. Further follow-up of this cohort will provide insight into antibody and avidity kinetics over time.
    • Towards improved process efficiency in vaccine innovation: The Vaccine Innovation Cycle as a validated, conceptual stage-gate model.

      Van de Burgwal, L H M; Ribeiro, C Dos S; Van der Waal, M B; Claassen, E (2018-11-26)
      Continuing investments in vaccine innovation are insufficiently translated into market entries of novel vaccines. This innovation paradox is in part caused by stakeholders lacking complete understanding of the complex array of steps necessary for vaccine development and collaboration difficulties between the wide variety of stakeholders involved. Models providing cross-domain understanding can improve collaboration but currently lack both comprehensibility and granularity to enable a prioritized view of activities and criteria. Key opinion leaders (KOLs) were asked to contribute to the definition of a vaccine innovation cycle (VIC). In a first step, 18 KOLs were interviewed on the stages (activities and results) and gates (evaluation criteria and outcomes) of vaccine innovation. This first description of the VIC was subsequently validated and refined through a survey among 46 additional KOLs. The VIC identifies 29 distinct stages and 28 corresponding gates, distributed in ten different but integrated workstreams, and comprehensibly depicted in a circular innovation model. Some stage-gates occur at defined moments, whereas the occurrence and timing of other stage-gates is contingent on a variety of contextual factors. Yet other stage-gates continuously monitor internal and external developments. A gap-overlap analysis of stage-gate criteria demonstrated that 5 out of 11 criteria employed by vaccine developers correspond with criteria employed by competent (regulatory) authorities. The VIC provides a comprehensive overview of stage-gates throughout the value chain of vaccine innovation. Its cyclical nature highlights the importance of synchronizing with unmet needs and market changes, and conceptualizes the difference between incremental and radical vaccine innovation. Knowledge on the gap between internal and external criteria will enhance the viability of newcomers to the field. The VIC can be used by stakeholders to improve understanding and communication in forming collaborative alliances and consortia. Such a boundary-spanning function may contribute to the reduction of process inefficiencies, especially in public-private partnerships.