NCT05965635

Brief Summary

An innovative way to prevent multiple tick-borne diseases is an anti-tick vaccine, i.e. targeting the vector to prevent transmission of pathogens from the tick to the host. The rationale for an anti-tick vaccine stems from a phenomenon coined tick immunity. This study aims to show proof of concept that humans indeed develop immunity to ticks. Therefore subjects will be challenged three to four times with ticks reared in colony from a designated laboratory and that are exhaustively tested negative for various known tick-borne pathogens. Several tick feeding parameters will be evaluated to assess the development of tick immunity in the subjects. To this end, a total amount of ten ticks per challenge will be placed under a dressing placed on the forearm. The primary study endpoint is the tick feeding phenotype. Secondary parameters are signs of an immune response in the host; itch, redness, or other signs of a (local) immune response (blood and skin biopsies). All parameters, except for the skin biopsies, will be collected/evaluated after each tick challenge.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
11

participants targeted

Target at below P25 for not_applicable

Timeline
Completed

Started Jul 2023

Typical duration for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

March 28, 2023

Completed
4 months until next milestone

Study Start

First participant enrolled

July 25, 2023

Completed
3 days until next milestone

First Posted

Study publicly available on registry

July 28, 2023

Completed
2.6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

March 2, 2026

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

March 2, 2026

Completed
Last Updated

March 24, 2026

Status Verified

March 1, 2026

Enrollment Period

2.6 years

First QC Date

March 28, 2023

Last Update Submit

March 20, 2026

Conditions

Tick BitesImmunity to Ticks

Keywords

Tick bitesIxodus scapularisTick Challenge modelTick borne diseasesTick immunity

Outcome Measures

Primary Outcomes (4)

  • Tick weight

    Tick weight in mg

    Up to 1 week

  • Tick feeding molting success

    Molting success rate

    Up to 1 week

  • Tick survival

    tick survival rate

    Up to 1 week

  • Tick attachment

    tick attachment rate

    Up to 1 week

Secondary Outcomes (4)

  • Signs of an immune response in the host: Itch

    Up to 1 week

  • Signs of an immune response in the host: redness

    Up to 1 week

  • Signs of an immune response in the host: other

    3 weeks

  • Signs of an immune response in the host: biopsies

    9 weeks

Study Arms (1)

Experimental

EXPERIMENTAL
Other: Ixodus scapularis nymphs

Interventions

Ixodus scapularis nymphsOTHER

Tick challenge

Experimental

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Age: 18 years and older;
  • Negative Borrelia VlsE1/pepC10 ELISA.

You may not qualify if:

  • Known history of tick bites;
  • Positive Borrelia serology (VlsE1/PepC10 ELISA);
  • Known history or current suspicion on any tick-borne disease;
  • Chronic skin condition affecting the arm skin;
  • Inability to maintain the dressing for any reason;
  • Known immunodeficiency or autoimmune disease;
  • Use of systemic immunomodulating drugs or chemotherapy, current or in the past;
  • Chronic use of antibiotics;
  • Unable to give informed consent or do not have a thorough command of the Dutch language;
  • Refusal to participate in specimen collection and storage for future study related use;
  • Pregnant or breastfeeding women;
  • Not willing to use adequate contraception during the study period;
  • Red meat allergy (both medically confirmed and self-reported);
  • Use of investigational therapy and devices during the time of the study;
  • Any other condition that, in the opinion of the investigator, would make the patient unsuitable for enrolment or could interfere with the patient participating in and completing the study.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

AUMC location AMC

Amsterdam-Zuidoost, North Holland, 1105 AZ, Netherlands

Location

MeSH Terms

Conditions

Tick BitesTick-Borne Diseases

Condition Hierarchy (Ancestors)

Bites and StingsPoisoningChemically-Induced DisordersWounds and InjuriesVector Borne DiseasesInfections

Study Design

Study Type
interventional
Phase
not applicable
Allocation
NA
Masking
NONE
Purpose
BASIC SCIENCE
Intervention Model
SINGLE GROUP
Model Details: Single centre, experimental study
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
PI

Study Record Dates

First Submitted

March 28, 2023

First Posted

July 28, 2023

Study Start

July 25, 2023

Primary Completion

March 2, 2026

Study Completion

March 2, 2026

Last Updated

March 24, 2026

Record last verified: 2026-03

Data Sharing

IPD Sharing
Will not share

Locations

NL(1)