EXPERT REACTION: Australia secures two new potential coronavirus vaccines

This is a good option to have advance purchase agreements with 3 of the leading vaccine candidates and including 3 different vaccine platforms (mRNA, viral vector and protein subunit). This is in addition to the recent government announcement to assist in providing vaccines and readiness in a neighbouring countries. Of note there are logistical challenges with getting these vaccines from production sites to the individual person. 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.

Two agreements have been signed by the Australian Government to provide access to a further two COVID-19 vaccines currently in phase 3 trials. This will mean that four different COVID-19 vaccines will be available early next year. Health and aged care workers plus vulnerable Australians will be the first to receive these vaccines. Key questions which will need to be considered include the following:

•  Are individuals being offered vaccination receiving one or all the available vaccines? If a multiple vaccine approach taken this may raise further concerns over unexpected immune reactions.
   
• If only one of the vaccines is offered to an individual then the question arises of which one will offer the greatest efficacy (level of protection)? Will recipients be able to choose which vaccine they receive?
   
• If an individual receives a vaccine with a lower efficacy compared to another can the individual receive another COVID-19 vaccine with a higher level of efficacy at a future date?
   
• Will costs associated with different vaccine preparations determine which COVID-19 vaccine offered to an individual?

Being able to secure a supply of several different COVID-19 vaccines ensures Australians have safe access to a vaccine that provides some level of protection against COVID-19. The level of protection provided by the vaccine one receives may mean that some Australians have a greater level of protection than others.

This is very good news. Australia must diversify it’s 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.

The announcements of these two additional vaccine deals from the Australian government give us a greater chance of being able to deliver a vaccine to those who need it next year. We don’t know which of the number of vaccines currently being developed and trialled will prove to be safe and effective and so it makes sense not to ‘put all your eggs in one basket’ as Prime Minister Scott Morrison has said.

It is important that the four vaccines that Australia has signed deals for are taking various approaches, which also makes sense in terms of giving Australia the best possible chance of having a vaccine that can be used next year. All of the vaccines that Australia has deals for are expected to require individuals to receive two doses.

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 I and II 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 III 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 tool-kit. 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.

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 other two vaccines announced in today (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.

The announcement of an agreement to supply two additional vaccines to Australia is truly exciting news. The existing agreements already give us a strong position in terms of access to two vaccines that still look very promising however adding two additional vaccines that are slightly different to those we are already positioned to have access to increases our chances of having a safe and effective vaccine available to as many Australians as possible in as short a time frame as possible.
 
In terms of the Novavax vaccine, this vaccine is based on advanced technology that is different from the other vaccines we have been hearing about mostly. It is a protein-based vaccine targeting the spike protein of the SARS-CoV-2 virus which is the protein the virus uses to get into cells to infect them. The fact that it’s a protein-based vaccine means it is made in the lab basically using the genetic sequence of the virus as a template and therefore there is no live virus involved at any stage and the vaccine does not contain any viruses at all and can’t reproduce or replicate. It also isn’t a genetic vaccine and so doesn’t include RNA or DNA that use people’s cells after the vaccine is injected to make the spike protein.

Novavax have, over a number of years, developed a clever technique where they assemble protein-based antigens into small particles that, to immune cells, resemble viruses to help generate a strong immune response. The vaccine also contains Novavax’s patented adjuvant, Matrix-M, which has a track record of safely enhancing immune responses when added to their vaccines. In preclinical trials, NVX CoV2373 demonstrated an indication of antibodies that block binding of the spike protein to receptors targeted by the virus, a critical aspect for effective vaccine protection and Phase 1 trials published in The New England Journal of Medicine demonstrated this vaccine is safe and effective. Phase 2 and 3 trials are underway currently.
 
The Pfizer/BioNTech vaccine is based on novel mRNA technology and also looks promising. Preclinical results, as well as Phase 1 clinical trial results also published in The New England Journal of Medicine, showed a strong immune response and large scale phase 2/3 trials are underway.