Australians will get access to 84.8 million COVID-19 vaccine doses throughout 2021, provided current trials prove the vaccines in question are safe and effective.

A series of deals worth A$1.7 billion between the federal government and two major pharmaceutical companies would see the local production and supply of two vaccines, developed by the University of Oxford and the University of Queensland, respectively.

A recap of the vaccine trials

Oxford and AstraZeneca have what’s called a viral vector vaccine. Researchers take a fairly harmless virus (in this case an adenovirus from chimpanzees) and modify it to produce a target (here they’ve used the spike protein of SARS-CoV-2, the coronavirus that causes COVID-19).

A viral vector looks like a virus to our immune system, so the idea is it can train our body to mount a strong response against SARS-CoV-2. But the viral vector can’t cause disease.

The University of Queensland and CSL have a protein subunit vaccine, which also uses the spike protein as a target. Unfortunately, spike protein is notorious for changing its shape, which makes it harder for our immune system to recognise.

So the University of Queensland has developed a molecular clamp to hold the spike protein in the correct shape. The clamped spike is then mixed with an adjuvant, a compound that stimulates an immune response. The adjuvant here is MF59, used in some influenza vaccines for older people.

AstraZeneca has started vaccinating volunteers as part of phase 3 clinical trials in the United States, while CSL and the University of Queensland are vaccinating volunteers for their phase 1 clinical trial in Australia.

What happens next?

All eyes will be on the phase 3 trial results for AZD1222, expected in October. If these are good, the government, AstraZeneca and CSL would need to finalise a formal agreement and production could proceed.

Even if AZD1222 is successful, the V451 clinical trials remain essential. V451 could potentially be more effective or better suited to specific groups, especially older people. It could also potentially be used to boost responses after AZD1222 vaccination. It’s a crucial card to have up our sleeve.