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Singapore Clinical Research Institute (SCRI)

PRIBIVAC

Find out how the PRIBIVAC trial is studying the best COVID-19 booster strategies, comparing different vaccine combinations to guide future vaccination programmes.

Last updated on 17 March 2026

PRIBIVAC is an adaptive, randomised, subject-blinded, controlled trial to assess a heterologous prime-boost-boost strategy in comparison with a homologous regimen in order to compare short and long-term immunogenicity of different COVID-19 vaccine combinations. It will help to address the following fundamental questions for the COVID-19 vaccination programs: Who needs a booster vaccination? How long after the primary series should it be administered? And, which vaccine should be used?

Compared with other COVID-19 vaccination trials, PRIBIVAC is unique as

  • All participants have mRNA primary vaccines series;

  • Multiple heterologous boost COVID-19 vaccine regimens have involved;

  • Comprehensive immune evaluation

The comprehensive immunogenicity evaluation is carried out through a collaboration between A*STAR Infectious Diseases Labs, Singapore Immunology Network, Duke-NUS Medical School, National Public Health Laboratory and KK Women’s and Children’s Hospital, which showcases the capabilities and strong partnerships between Singapore research teams.

The study team also comprised

  • A clinical site at The National Centre for Infectious Diseases (NCID) Research Clinic

  • A vaccination site at P.H Feng Research Centre located at NCID

  • An academic CRO at Singapore Clinical Research Institute (SCRI)

SCRI is proud to support NCID in initiating the study in just two weeks by preparing the site, training project teams, drawing up research monitoring and data collection plans and facilitating ethics submissions. In addition, the study database was managed to go-live within 1 month with the efforts to speed up the work which usually takes 3 months. The first data safety monitoring board meeting was achieved within 1 week upon the availability of the immunogenicity data. As the study is in an adaptive design, new intervention groups will be added depending on what COVID-19 vaccines are authorised for use in Singapore as the study progress. With the able support from SCRI, the implementation of each new intervention group so far has been achieved efficiently.

Our team will also continue to provide services in project management, site and data safety monitoring as well as data management and analysis for the study.