NCT05415267

Brief Summary

It is important people receiving immunosuppressive therapy are provided with the best protection against COVID-19 because they are at greater risk of severe illness should they become infected. As severe immunosuppression can reduce the efficacy of COVID-19 vaccination, doctors agree that COVID-19 boosters is are important to maximise the vaccine response in these people. However, we don't currently know the best time to give booster vaccines to people about to start immunosuppressive therapy. This research aims to address this knowledge gap by examining whether the greatest protection is provided by giving the COVID-19 booster just before the immunosuppressive therapy starts or by waiting and giving the booster 6 months after treatment start. At the 6-month timepoint, in many cases the more intensive immunosuppression is often weaning and the immune system is starting to rebuild.

Trial Health

77
On Track

Trial Health Score

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

Enrollment
320

participants targeted

Target at P25-P50 for phase_3 covid19

Timeline
7mo left

Started Jul 2023

Longer than P75 for phase_3 covid19

Geographic Reach
1 country

5 active sites

Status
recruiting

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

Study Progress84%
Jul 2023Dec 2026

First Submitted

Initial submission to the registry

June 8, 2022

Completed
5 days until next milestone

First Posted

Study publicly available on registry

June 13, 2022

Completed
1.1 years until next milestone

Study Start

First participant enrolled

July 21, 2023

Completed
3.4 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 31, 2026

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 31, 2026

Last Updated

February 24, 2026

Status Verified

February 1, 2026

Enrollment Period

3.4 years

First QC Date

June 8, 2022

Last Update Submit

February 21, 2026

Conditions

Keywords

VaccinationImmunology

Outcome Measures

Primary Outcomes (1)

  • Anti-SARS-CoV-2 neutralising antibody (NAb) response over 12 months

    Integrated time-weighted area under the curve (AUC) change from baseline in anti-SARS- CoV-2 NAb over 12 months from a SARS-CoV-2 booster vaccination

    48 weeks

Secondary Outcomes (6)

  • Tetanus toxoid NAb response over 12 months

    48 weeks

  • Safety of immediate versus deferred COV-19 booster vaccination

    48 weeks

  • Efficacy of immediate versus deferred COV-19 booster vaccination

    48 weeks

  • Analysis of the response to the SARS-CoV-2 booster vaccination

    48 weeks

  • Assessment of SARS-CoV-2 antibody responses in study populations stratified by their broad qualifying disease types

    48 weeks

  • +1 more secondary outcomes

Other Outcomes (1)

  • Level of SARS-CoV-2 protection over time

    48 weeks

Study Arms (4)

Group 1 Arm A

ACTIVE COMPARATOR

Immediate SARS-CoV-2 booster at week 0 and booster of combined diphtheria toxoid/tetanus toxoid (dT vaccine) at week 24.

Biological: diphtheria and tetanus toxoids (adsorbed) vaccineBiological: COVID-19 vaccine

Group 1 Arm B

ACTIVE COMPARATOR

dT vaccine at week 0 and SARS-CoV-2 deferred booster at week 24.

Biological: diphtheria and tetanus toxoids (adsorbed) vaccineBiological: COVID-19 vaccine

Group 2 Arm C

ACTIVE COMPARATOR

Immediate SARS-CoV-2 booster at week 0.

Biological: COVID-19 vaccine

Group 2 Arm D

ACTIVE COMPARATOR

Delayed SARS-CoV-2 booster at week 24

Biological: COVID-19 vaccine

Interventions

The diphtheria/tetanus toxoids vaccine will be given to participants enrolled into Group 1 as a comparator vaccine to the mRNA COVID-19 booster vaccine with the aim of determining whether the results related to COVID-19 vaccine timing also apply to more traditional protein-based vaccines.

Also known as: ADT Booster
Group 1 Arm AGroup 1 Arm B

All participants will receive a COVID-19 booster vaccination at either week 0 or week 24 depending on their randomised study arm

Group 1 Arm AGroup 1 Arm BGroup 2 Arm CGroup 2 Arm D

Eligibility Criteria

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

You may qualify if:

  • Adult aged at least 18 years
  • Previously vaccinated with 2 (or more) doses of any licensed COVID-19 vaccine who requires initiation of moderate-to-severe immunosuppression; most recent COVID-19 vaccine dose must have been given \> 3 months prior
  • Planned significant immunosuppressive therapy for at least 1 year
  • No cyclophosphamide, alemtuzumab or rituximab treatment in the past 5 years. Note: patient may have concurrent steroids with any treatments listed in protocol
  • Voluntarily given written informed consent

You may not qualify if:

  • Pregnant or breastfeeding
  • Has underlying primary immunodeficiency
  • Has received or likely to receive intravenous/subcutaneous immunoglobulin (IVIg/ScIg).
  • Projected treatment is likely to involve plasma exchange
  • Contraindication to receipt of SARS-CoV-2 vaccine
  • Intolerance of or previous allergic reaction to tetanus vaccination
  • Patients switching immunosuppressive therapies following enrolment with an absolute lymphocyte count \<0.5 x 109/L immediately prior to screening

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (5)

Blacktown Hospital

Blacktown, New South Wales, 2148, Australia

RECRUITING

Royal Prince Alfred Hospital

Camperdown, New South Wales, 2050, Australia

RECRUITING

Concord General Repatriation Hospital

Concord, New South Wales, 2137, Australia

RECRUITING

St Vincent's Hospital, Sydney

Darlinghurst, New South Wales, 2010, Australia

RECRUITING

Westmead Hospital

Westmead, New South Wales, 2145, Australia

RECRUITING

Related Publications (1)

  • Zorger AM, Hirsch C, Baumann M, Feldmann M, Brockelmann PJ, Mellinghoff S, Monsef I, Skoetz N, Kreuzberger N. Vaccines for preventing infections in adults with haematological malignancies. Cochrane Database Syst Rev. 2025 May 21;5(5):CD015530. doi: 10.1002/14651858.CD015530.pub2.

MeSH Terms

Conditions

COVID-19

Interventions

Tetanus ToxoidVaccinesCOVID-19 Vaccines

Condition Hierarchy (Ancestors)

Pneumonia, ViralPneumoniaRespiratory Tract InfectionsInfectionsVirus DiseasesCoronavirus InfectionsCoronaviridae InfectionsNidovirales InfectionsRNA Virus InfectionsLung DiseasesRespiratory Tract Diseases

Intervention Hierarchy (Ancestors)

ToxoidsBiological ProductsComplex MixturesViral Vaccines

Study Officials

  • Sarah C Sasson, PhD

    The Kirby Institute UNSW Sydney

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Dianne L Carey, PhD

CONTACT

Study Design

Study Type
interventional
Phase
phase 3
Allocation
RANDOMIZED
Masking
NONE
Purpose
PREVENTION
Intervention Model
PARALLEL
Sponsor Type
OTHER GOV
Responsible Party
SPONSOR

Study Record Dates

First Submitted

June 8, 2022

First Posted

June 13, 2022

Study Start

July 21, 2023

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2026

Last Updated

February 24, 2026

Record last verified: 2026-02

Data Sharing

IPD Sharing
Will not share

Locations