More than 100 Victorians, aged 18 to 70, are being recruited to participate in a trial for the Melbourne-made RBD protein vaccine and RBD mRNA vaccine.
The new jabs, created by scientists from the Doherty Institute and Monash Institute of Pharmaceutical Science, are distinct from all existing vaccines.
They focus on the immune response on the tip of the SARS-CoV-2 spike protein, called the receptor binding domain.
The RBD enables the virus to enter and infect cells in the body and can elicit more than 90 per cent of neutralising antibodies to block the virus following infection.
The vaccines may also provide immunity to the Omicron variant and more serious future variants, as they are "proof-of-principle" variant vaccines.
"As well as inducing strong neutralising antibody immunity to the Beta variant in mice, it also retains its potential to neutralise the original ancestral strain, and preliminary in-lab studies have demonstrated neutralising activity against other variants including Delta and Omicron," Doherty Institute researcher Georgia Deliyannis said.
She said the RBD protein vaccine protected against COVID-19 in a mouse even 100 days after it was given the jab.
Doherty Institute Director Sharon Lewin said the emergence of new COVID-19 variants showed the need for the next generation of vaccines.
"Both vaccines are efficient to produce and can be rapidly modified to incorporate distinct or multiple RBD mutations arising in future variants," she said.
"In addition, Australia needs the ability to manufacture its own vaccines to ensure our own supply should future global shortages occur, and to contribute to the global need for COVID-19 vaccines."
Some 114 volunteers are needed to participate in trials to assess the safety and efficacy of a single dose of the vaccines as a fourth COVID-19 dose.
Participants must have had their third dose at least three months prior to the study commencing.
People who have been infected with COVID-19 are eligible so long as it's been at least three months since infection and they've received a third dose.
Victoria reported nine COVID-19 deaths in the 24 hours to midnight on Thursday, in people aged in their 50s, 80s and 90s.
Six of the deaths occurred in the past week, one in early March and the other two happened in February.
The state's health department reported 9244 new COVID-19 infections and 253 cases in hospital, including 19 in ICU and four on a ventilator.
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