What is COVAX-19, the most advanced of Australia’s remaining local COVID vaccine candidates?
June 23, 2021 12.37pm AEST
Australia’s current crop of COVID-19 vaccines consists of a shot by American biotechnology company Pfizer, which we import, and the vaccine by British-Swedish multinational AstraZeneca, the bulk of which we manufacture onshore in Melbourne under license.
We don’t currently have a locally-made COVID vaccine at our disposal, though this week the Victorian government announced funding for a Pfizer-style mRNA vaccine developed by Monash University. It will move to phase 1 trials in October or November.
However, the most advanced of our local COVID vaccines in development is a shot called “COVAX-19” by South Australian based biotech, Vaxine.
It’s great to see another Australian group at the forefront of COVID-19 research and particularly vaccine development.
How does the Novavax vaccine work?
The Novavax vaccine is given as two doses, similar to the Pfizer and AstraZeneca shots already being used in Australia.
It can be stored for up to three months at fridge temperature, which differs from the Pfizer mRNA vaccine which needs to be kept at ultra-low temperatures. In saying that, the TGA said last week the Pfizer vaccine can be stored at normal freezer temperatures for two weeks during transport, and at fridge temperatures for five days — though must still be kept ultra-cold after transport and in the long-term.
The vaccine also uses a different technology to the Pfizer and AstraZeneca vaccines. It’s a “protein subunit” vaccine; these are vaccines that introduce a part of the virus to the immune system, but don’t contain any live components of the virus.
The protein part of the vaccine is the coronavirus’ “spike protein”. This is part of the other COVID-19 vaccines in use but in a different form.
The Novavax vaccine uses a version of the spike protein made in the lab. The spike proteins are assembled into tiny particles called “nanoparticles” which aim to resemble the structure of the coronavirus, however they cannot replicate once injected and the vaccine cannot cause you to get COVID-19.
In order for these subunit vaccines to generate strong protective responses, they need to include molecules that boost your immune system, called “adjuvants”. The goal of these adjuvants is to mimic the way the real virus would activate the immune system, to generate maximum protective immunity.
Novavax includes an adjuvant based on a natural product known as saponin, an extract from the bark of the Chilean soapbark tree.
How effective is the vaccine compared to those already in use in Australia?
The interim data from phase 3 testing, released in March, was very encouraging. When tested in the UK in a clinical trial including more that 15,000 people, the vaccine was 96% effective at preventing COVID-19 disease for those infected with the original strain of the coronavirus.
This compares well to the Pfizer vaccine, with an efficacy of 95%, and recent data from AstraZeneca demonstrating 76% efficacy against COVID-19.
The Novavax vaccine is also safe. In early clinical testing the vaccine caused mainly mild adverse events such as pain and tenderness at the injection site, and no serious adverse reactions were recorded. In the larger trials, adverse events occurred at low levels and were similar between the vaccine and placebo groups.
COVID Vaccine Rollout: Anthony Albanese has slammed Prime Minister Scott Morrison for the delay in Australia’s Novavax vaccines. 51 million doses expected to arrive later this year will now only be available from 2022, which the Opposition Leader says is a “further setback” on Australia’s road to recovery from COVID-19.
“Scott Morrison had two big jobs this year – the rollout of the vaccine and effective national quarantine – and unfortunately, both of them have been botched.”