Victorians sought for trial investigating impact of reduced doses of COVID-19 booster shots

Young girl being vaccinated
Eight hundred Victorians are being sought for a trial investigating the impact of vaccinating people with a lower dose of a COVID-19 booster shot.

The Coalition for Epidemic Preparedness Innovations (CEPI) and the Murdoch Children’s Research Institute (MCRI) are leading the global trial that aims to improve acceptability and increase access to COVID-19 vaccines. The study would also secure additional data on administering ‘mix-and-match’ COVID-19 vaccine schedules.

Participants, aged 18 years and older in Victoria, who have not yet received a COVID-19 vaccine booster are being recruited. They would receive either the Pfizer or Moderna vaccine and be followed for up to 12 months.

Trial lead, Murdoch Children’s Professor Kim Mulholland, said the findings were expected to provide important data on the advantages of vaccinating people with a lower booster dose of a COVID-19 vaccine which could guide future vaccination strategies.

“All countries are struggling with the issue of how best to maintain COVID-19 immunity in their populations,” he said. Our trial will specifically examine how best to vaccinate communities with follow-up booster shots and the timings around these subsequent booster doses. While reduced doses could provide the opportunity for large financial savings for countries, they are also likely to produce less side effects, improving their uptake.

The launch of the trial follows a recent statement made by the World Health Organization urging broader global access to COVID-19 vaccines for both primary vaccinations and booster doses to maintain COVID-19 immunity in light of the emergence and impact of new variants like Omicron.

Administering reduced vaccine shots has previously been used to maximise global vaccine supply during outbreaks of yellow fever and polio. The Murdoch Children’s also recently published supportive research for this dose-sparing strategy for the experimental rotavirus vaccine, RV3-BB.

CEPI will provide up to $12.3 million in funding to the global trial led by the Murdoch Children’s in collaboration with Padjadjaran University and the University of Indonesia in Indonesia, and the Government of Mongolia, and with support from the global non-profit organisation PATH. The study is the first under CEPI’s program of work looking at reduced COVID-19 booster shots. In line with CEPI’s access policy, access to the trial data will be shared through open-access publications and via scientific meetings to ensure all can benefit from the research findings.

Participants in Victoria would be required to visit The Royal Children’s Hospital for four blood tests, complete an online diary card for seven days post vaccination, and receive three follow up calls.

For more on the trial visit or email

Available for interview:

Professor Kim Mulholland, Murdoch Children’s Group Leader, New Vaccines

Media Contact:

Bridie Byrne
MCRI media manager
+61 457 365 848

About MCRI

The Murdoch Children's Research Institute (MCRI) is the largest child health research institute in Australia committed to making discoveries and developing treatments to improve child and adolescent health in Australia and around the world. They are pioneering new treatments, trialling better vaccines and improving ways of diagnosing and helping sick babies, children and adolescents. It is one of the only research institutes in Australia to offer genetic testing to find answers for families of children with previously undiagnosed conditions.


CEPI will provide up to $12.3 million in funding to the global trial.