Booster Study of SpikoGen COVID-19 Vaccine

September 16, 2025 updated by: Vaxine Pty Ltd

Immunogenicity and Safety Study in Ambulatory Adults of a Single Intramuscular Dose of SpikoGen Vaccine as a Heterologous or Homologous Booster Dose Following Completion of a Primary Course of Covid-19 Vaccine

The purpose of the study is to assess the effectiveness of Spikogen vaccine when used as a 3rd or 4th dose booster in adults who have been previously vaccinated with any Covid-19 vaccine types, including mRNA vaccine, adenoviral vector vaccines, recombinant protein vaccines, or inactivated virus vaccines.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Currently in Australia, mRNA, adenoviral vector and recombinant protein vaccines have provisional approval for use as 3rd or 4th booster doses. This study will provide important data on the use of Spikogen as an alternative recombinant protein booster vaccine. The study will provide data in ambulatory adults on the safety and effectiveness of Spikogen vaccine when administered as a single intramuscular booster dose in those who previously vaccinated with mRNA vaccine in comparison to those immunised with other Covid-19 vaccine platforms.

Study Type

Interventional

Enrollment (Actual)

81

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Australia
    • South Australia
      • Adelaide, South Australia, Australia, 5042
        • ARASMI

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Able to provide written informed consent
  • Males or females 18 years of age or older
  • Have previously had a primary course of Covid-19 vaccine with the most recent dose no less than 3 months previously.
  • Understand and are likely to comply with planned study procedures and be available for all study visits.

Exclusion Criteria

  • Allergy to Spikogen vaccine or one of its components, e.g. polysorbate 80.
  • Have received an experimental agent within 30 days prior to the study vaccination or expect to receive another experimental agent during the trial reporting period.
  • Any serious medical, social or mental condition which, in the opinion of the investigator, would be detrimental to the subjects or the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: SpikoGen vaccine
Single booster dose of SpikoGen Covid-19 vaccine
Biological: SpikoGen vaccine
Recombinant spike protein based Covid-19 vaccine
Other Names:
  • Covax-19

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Seroconversion
Time Frame: Between baseline and 4 weeks post the booster dose
Proportion of study participants who seroconvert (4-fold or greater rise in serum spike antibody) by primary vaccine group
Between baseline and 4 weeks post the booster dose
Seroprotection
Time Frame: Between baseline and 4 weeks post the booster dose
Proportion of study participants who achieve a spike protein neutralisation titer of 32 or greater by primary vaccine group
Between baseline and 4 weeks post the booster dose
Geometric mean titer fold change
Time Frame: Between baseline and 4 weeks post the booster dose
Increase in Geometric mean titer of spike neutralisation antibodies by primary vaccine group
Between baseline and 4 weeks post the booster dose
Safety assessment 1
Time Frame: Occurring within 7 days after booster dose.
Frequency of Adverse events by primary vaccine group
Occurring within 7 days after booster dose.
Safety assessment 2
Time Frame: Between time of administration of booster dose and through study completion, an average of 3 months
Frequency of Serious Adverse events by primary vaccine group
Between time of administration of booster dose and through study completion, an average of 3 months
SARS-CoV-2 infection
Time Frame: Between time of administration of booster dose and through study completion, an average of 3 months
Frequency of SARS-CoV-2 infections in study participants by primary vaccine group, age, gender, co-morbidities, and past infection
Between time of administration of booster dose and through study completion, an average of 3 months
Antibody durability
Time Frame: Between time of administration of booster dose and through study completion, an average of 3 months
The proportion of subjects who remain seroprotected throughout the duration of the study including broken down by primary vaccine group.
Between time of administration of booster dose and through study completion, an average of 3 months
Seroconversion in participants with and without evidence of past infection
Time Frame: Between baseline and 4 weeks post the booster dose and through study completion, an average of 3 months
Spike antibody seroconversion in baseline nuclear protein antibody positive versus negative participants by primary vaccine group
Between baseline and 4 weeks post the booster dose and through study completion, an average of 3 months
Seroprotection in participants with and without evidence of past infection
Time Frame: Between baseline and 4 weeks post the booster dose and through study completion, an average of 3 months
Spike antibody seroprotection in baseline nuclear protein antibody positive versus negative participants by primary vaccine group
Between baseline and 4 weeks post the booster dose and through study completion, an average of 3 months
Spike antibody GMT in participants with and without evidence of past infection
Time Frame: Between baseline and 4 weeks post the booster dose and through study completion, an average of 3 months
Spike antibody GMT in baseline nuclear protein antibody positive versus negative participants by primary vaccine group.
Between baseline and 4 weeks post the booster dose and through study completion, an average of 3 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Antibody correlates of protection
Time Frame: Baseline and 4 weeks post the booster dose, and through study completion, an average of 3 months
SARS-CoV-2 antibody levels in subjects with or without breakthrough SARS-CoV-2 infection
Baseline and 4 weeks post the booster dose, and through study completion, an average of 3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Vaxine Pty Ltd

Collaborators

Cinnagen
Australian Respiratory and Sleep Medicine Institute Ltd

Investigators

  • Principal Investigator: Dimitar Sajkov, MD/PhD, ARASMI
  • Study Director: Nikolai Petrovsky, MD/PhD, Vaxine Pty Ltd

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 7, 2022

Primary Completion (Actual)

December 31, 2023

Study Completion (Actual)

September 16, 2025

Study Registration Dates

First Submitted

September 8, 2022

First Submitted That Met QC Criteria

September 13, 2022

First Posted (Actual)

September 16, 2022

Study Record Updates

Last Update Posted (Estimated)

September 17, 2025

Last Update Submitted That Met QC Criteria

September 16, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AUST-C19-booster

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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