Third Dose of Moderna COVID-19 Vaccine in Transplant Recipients

A Randomised, Blinded, Controlled Trial of a Third Dose of Moderna COVID-19 Vaccine Versus Placebo in Solid Organ Transplant Recipients

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04885907

Enrollment

120

Registered

2021-05-13

Start date

2021-05-25

Completion date

2021-08-30

Last updated

2022-08-02

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

Conditions

Covid19, Immune Suppression, Vaccine Response Impaired

Keywords

solid organ transplant, vaccine

Brief summary

This study will be a randomized, double-blind, placebo-controlled trial of a third dose of Moderna vaccine versus placebo. Participants will be those that have received two doses of mRNA-1273 COVID vaccine (Moderna) at 0 and 1 months. Participants will be randomized 1:1 to receive either a third dose of the mRNA-1273 vaccine or saline placebo at 3 months post initial vaccination.

Detailed description

Solid organ transplant (SOT) recipients are at high risk of COVID-19 complications. The Moderna vaccine (mRNA-1273) has proven highly efficacious and safe in a phase III large, randomized controlled trial of 30,420 persons in the general population, and has been in use in Canada since December 2020. SOT patients show diminished response to mRNA vaccines in several studies with approximately 40-50% positive antibody after the second dose. In positive patients, antibody titers are lower than the general population and adverse events mirror the general population. The current study will recruit 120 SOT recipients who have received both scheduled doses of the Moderna vaccine at 0 and 1 months. The hypothesis is that a third dose of vaccine will significantly increase antibody titers. SOT participants will be recruited and randomized 1:1 to receive an additional dose of Moderna COVID-19 vaccine two months after the last dose vs saline placebo. The outcomes will measure anti-RBD antibody titer, T-cell immunity, local/systemic side effects, and rejection events.

Interventions

BIOLOGICALmRNA-1273 vaccine

COVID vaccine 3rd dose

OTHERNormal Saline Placebo

Normal Saline Placebo

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

DOUBLE (Subject, Caregiver)

Masking description

Participant and vaccinator will be blinded to vaccine vs placebo

Intervention model description

Randomised, placebo-controlled trial

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Solid organ transplant recipient who has previously received Moderna vaccine at 0 and 1 months * Able to provide informed consent

Exclusion criteria

* Anaphylaxis or allergic reaction to Moderna vaccine

Design outcomes

Primary

Measure	Time frame	Description
anti-RBD antibody titer	4-6 weeks after intervention	Percentage of patients that achieve anti-RBD of \>=100 U/mL in each arm

Secondary

Measure	Time frame	Description
Adverse events	7 days after intervention	Percentage of patient with local and systemic adverse events
T-cell response	4-6 weeks after intervention	Proportion of participants with an increase in polyfunctional T-cell response compared to pre-vaccination

Other

Measure	Time frame	Description
SARS-CoV-2 infection	6 months after intervention	Number of patients with microbiologically proven infection
Rejection	4 weeks after intervention	Proportion of patients with biopsy-proven or clinically treated graft rejection

Countries

Canada

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 20, 2026