Australian COVID-19 Vaccines Show Improved Immune Response: Researchers

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Two Australian COVID-19 vaccines have shown potential to be an improved approach to boosting immunity against COVID-19, according to researchers at the Peter Doherty Institute and Monash University.

Published in The Lancet’s eBioMedicine, 76 healthy adults from Melbourne, aged 18 to 64 and previously vaccinated with approved COVID-19 vaccines, were randomly selected to receive a fourth dose of the new vaccines.

The vaccines showed a robust immune response, even at the lowest tested dose. Moreover, they demonstrated no safety concerns.

“So far, both preclinical and clinical studies have shown our receptor binding domain (RBD) mRNA vaccine to provide a strong boost at low doses, suggesting the very real potential to develop a multivalent vaccine on an annual basis and to protect against emerging new variants of COVID-19, which are believed to be the root cause behind the ongoing ‘waves’ we are still experiencing,” Medical Indemnity Protection Society (MIPS) Prof. Colin Pouton noted.

The two RBD vaccine candidates under consideration:

1. RBD Protein Vaccine: This candidate utilises an engineered portion of the virus protein to trigger an immune response. It does not involve genetic material or another virus.
2. RBD mRNA Vaccine: This candidate involves the virus’s genetic sequence in the form of mRNA, which codes for the spike’s tip. This, in turn, results in the production of the RBD protein in the recipient.

He mentioned that the vaccines can potentially address immune imprinting, where the immune system remembers past viruses and shapes its response to new variants.

Addressing immune imprinting is vital for developing next-generation vaccines, he said, but challenges remain.

“New strategies are still needed to improve the efficacy of COVID-19 variant vaccines and to reduce death rates, particularly among older and vulnerable patients,” he added.

According to the Australian Bureau of Statistics, about 20,170 of 627,645 death registrations were of people who died from COVID-19 between March 2020 and Sept. 2023.

The highest number of deaths were observed in 80-89-year-olds.

Meanwhile, the death rate is 1.7 times higher in Aboriginal and Torres Strait Islander people than in non-Indigenous people. 

Doherty Institute Prof. Terry Nolan said the team was optimistic about the vaccines.

He said the vaccine’s targeted approach could make a compelling case to advance to the next phase of clinical trials, noting it will require additional funding and support from the industry.

Australian Government Medical Research Future Fund, and philanthropies Jack Ma Foundation and IFM investors funded the study.

Concerns About Modelling

It comes as Australia Institute Chief Economist Richard Dennis expressed concerns about previous COVID-19 modelling from the Doherty Institute.

He said their models are simplified versions of reality with no clear evidence of safety.

“The modelling is hypothetical,” Mr. Dennis argued.

It also doesn’t help answer the question that all state premiers and the Prime Minister are now facing: What should the states do?

“It might be inconvenient to say this, but the Doherty Modelling simply doesn’t help answer that question,” he said.

The Queensland University of Technology Prof. Fiona McDonald affirmed this, adding that achieving 100 percent immunity “isn’t realistic.”

“Many vaccines do not provide full immunity (like the influenza vaccine, for example), and some don’t prevent transmission (like the influenza vaccine, for example),” she said.

Current Vaccines are the Optimal Choice: Health Minister

Meanwhile, Health Minister Mark Butler argued the current vaccines remain the best option for protection against COVID-19.

“The advice from our experts is the best vaccine is the one you can get. The technical advisors stressed that the existing vaccines that are in the system that are available today in pharmacies and your general practices still provide very good protection against severe disease,” he said.

He suggested people over 75 with compromised immunity, who haven’t had a booster in over six months, should get another readily available one.

“Clearly, COVID cases are rising right now. We do want to see particularly vulnerable Australians protected against severe disease,” he said.

Australia is into its next COVID wave, with cases of Omicron variants severe disease rising since August.

In Victoria, deaths from Oct. 25 to Nov. 21 increased to 166, while the average daily hospitalisations for COVID-19 decreased to 274 from the previous 326, remaining higher than in recent months but below the peak in May and June, according to government data (pdf).

Meanwhile, E.5 variant, also known as “Eris,” currently accounts for about 50 percent of cases in New South Wales.

“No Need to Panic”: Experts Assure

Associate Professor James Trauer reassures that there is no need to panic now.

“Overseas, several countries have passed through waves with these newer offshoots of BA.2 and other variants, usually with mild to moderate strain on their healthcare systems,” he told 9News.

“So there’s no need to panic, and it’s unlikely we'll need any population-wide restrictions,” he urged.

Professor Booy from the University of Sydney added that current conditions can be managed easily without reintroducing stringent restrictions.

“There will undoubtedly be an upsurge in cases, but the new wave, I think, will be easily body-surfed by most sensible people,” she said.