Australia secures two more vaccine candidates

The Australian Government has secured two more potential coronavirus vaccines for Australia. The advance purchase agreements will provide Australia with 40 million doses of the vaccine being developed by biotechnology company Novavax and 10 million doses of the vaccine being produced by Pfizer and BioNTech. Both vaccines are currently in phase 3 trials.

The addition of the vaccine candidates means that Australia has now entered into four separate agreements for the supply of COVID-19 vaccines, if they are proved to be safe and effective. The move will strengthen Australia’s position to access safe and effective vaccines when they become available.

Expert in influenza and emerging infectious diseases, Professor Raina MacIntyre is Head of the Biosecurity Program at the Kirby Institute at the University of NSW.

“This is very good news. Australia must diversify its vaccine portfolio, as of the many vaccine candidates, some will be more effective than others, and some will be safer than others.

“We do not know which ones are best on each front, and it would be risky to only have two vaccines lined up, in case we ended up with one which was poorly efficacious or had a safety signal post-licensure.

“In my view, we should diversify further. In the case of a vaccine against a new disease, until vaccines are rolled out in the post-licensure phase, we won’t know which ones are the safest and most efficacious,” Professor MacIntyre said.

RMIT Vice-Chancellor Research Fellow at RMIT University Dr Kylie Quinn added, “The announcement that Novavax and BioNTech/Pfizer have signed agreements towards supply with the Australian Government is an exciting development. Both of these vaccines have performed strongly in phase 1 and 2 clinical trials, generating larger immune responses than we see in patients that have recovered from COVID-19. This is promising as the size of the immune response is, currently, our best way of predicting whether or not these vaccines will protect against infection with SARS-CoV-2.

“The inclusion of the Novavax vaccine is particularly notable for vaccine delivery to older individuals. A similar vaccine for influenza is being tested by Novavax in a phase 3 clinical trial specifically in older individuals. The trial is still ongoing but initial results showed that the Novavax vaccine generated larger immune responses in older people as compared to the standard flu vaccine.

“The key thing here is that Australia is positioning itself to have more vaccines in its toolkit. This will hopefully enable the delivery of vaccines to more Australians and, crucially, delivery of vaccines tailored to the specific needs of vulnerable groups, such as older Australians.”

Senior Lecturer in Paediatrics and Child Health at the University of Sydney Associate Professor Nicholas Wood said that having advance purchase agreements with three of the leading vaccine candidates and including three different vaccine platforms — mRNA, viral vector and protein subunit — was a good option.

“Of note, there are logistical challenges with getting these vaccines from production sites to the individual person,” he said.

“All vaccines require cold chain management. The mRNA vaccines at the moment require storage and shipping at below zero degrees Celsius, which is a significant logistical challenge. However, thermostability testing is underway and there may be potential for it to be stored and transported in a less stringent way.”

RMIT University’s Associate Professor Taghrid Istivan explained that sourcing vaccines from different locations will improve the nation’s chances of ensuring supply of vaccines.

“The latest move by the Australian Government to secure access to two additional new types of COVID-19 vaccines will strengthen our chances in fighting and defeating the virus in Australia.

“The importance of this step is that two of the vaccines, which were announced earlier this year — AstraZeneca/Oxford University and the CSL/UQ vaccines — will be manufactured locally by CSL, while the [recently announced] vaccines — Novavax and Pfizer vaccines — will be manufactured offshore in the US and Europe. This will ensure a stable and secure supply of the vaccines from different origins.

“Furthermore, as the full assessment on the efficacy and duration of the immune responses of these vaccines is yet to be confirmed, due to their composition/structure and their mechanism in generating immune responses in recipients, it is very wise to secure access to different types of vaccines and making them promptly available to the Australian public once they are approved and manufactured locally and abroad.

“Medical researchers will have the opportunity to assess their efficacy and then possibly identify and recommend the most effective type for the foreseeable future.”

Image credit: ©stock.adobe.com/au/Daniel CHETRONI