Homologous vs Heterologous Third Vaccination in Kidney Transplant Recipients Kidney Transplant Recipients

Single Blinded Randomized Controlled Trial on BNT162b2 or mRNA-1273 (mRNA) vs Ad26COVS1 or ChAdOx1-S (Viral Vector) for Third Vaccination in Kidney Transplant Recipients Without SARS-CoV-2 Spike Protein Antibodies Following Full Vaccination

Status

UNKNOWN

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05324319

Acronym

BOOST_TX

Enrollment

200

Registered

2022-04-12

Start date

2021-06-15

Completion date

2022-12-31

Last updated

2022-04-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19

Brief summary

Randomized-controlled trial comparing homologous (mRNA vaccine) vs. heterologous (vector vaccine) for third SARS-CoV-2 vaccine dose in kidney transplant recipients not responding to initial prime-boost vaccination with an mRNA vaccine.

Interventions

DRUGAd26COVS1

Heterologous vaccination

DRUGChAdOx1 SARS2 Vaccine

Heterologous vaccination

DRUGBNT162B2

Homologous vaccination

DRUGmRNA-1273

Homologous vaccination

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

DOUBLE (Subject, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* patient has received a kidney transplantation * full SARS-CoV-2 vaccination with mRNA vaccine (two doses) at least 4 weeks before screening * \> 18 years of age * no SARS-CoV-2 spike protein antibodies at least 4 weeks after the second dose of an mRNA vaccine

Exclusion criteria

* acute illness with fever * Prior documented infection with SARS-CoV-2 * triple anticoagulation therapy * Subject is currently enrolled in or has not yet completed at least 30 days since ending other investigational device or drug trial(s), or subject is receiving other investigational agent(s) * Subject has known sensitivity or intolerance to any of the products to be administered for the purpose of this study * Subject has any kind of disorder that compromises the ability of the subject to give written informed consent and/or to comply with the study procedures * Subject is pregnant or breast feeding

Design outcomes

Primary

Measure	Time frame	Description
Seroconversion at 4 weeks	4 weeks	number of patients developing SARS-CoV-2 antibodies at 4 weeks after 3rd vaccination

Secondary

Measure	Time frame	Description
Seroconversion at 12 weeks	3 months	number of patients developing SARS-CoV-2 antibodies at 12 weeks after 3rd vaccination (\> 0.8 BAU/mL)
SARS-CoV-2 antibody levels at 4 weeks	4 weeks	SARS-CoV-2 antibody levels at 4 weeks after the third vaccination
SARS-CoV-2 antibody levels at 12 weeks	3 months	SARS-CoV-2 antibody levels at 12 weeks after the third vaccination
Seroconversion at 36 weeks	6 months	number of patients developing SARS-CoV-2 antibodies at 36 weeks after 3rd vaccination (\> 0.8 BAU/mL)

Countries

Austria

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026