Australia’s A$123 million contribution to a global vaccine initiative, announced earlier this week, means the country would have access to a wider pool of COVID-19 vaccines, should they pass clinical trials.
The agreement with the World Health Organisation-backed COVAX initiative currently covers nine vaccines, with another nine being considered. These are to be shared with other member countries, rich and poor, by the end of 2021.
However, the agreement may only cover up to half the doses Australia needs, if each person needs two doses. So countries are still free to negotiate their own vaccine deals with individual manufacturers, as Australia has done.
Here’s what you need to know about the nine vaccines COVAX is currently backing, which are at various stages of development. These include pre-clinical animal testing and human clinical trials, which move through three phases. During the pandemic, some of these phases have been combined.
1. INO-4800 comes with a zap
After the vaccine is injected, a hand-held device delivers a short electrical pulse. This pulse opens small pores in your cells to allow the vaccine to enter.
Once inside your cells, instructions in the vaccine’s DNA are used to make copies of the full spike protein of SARS-CoV-2, the virus that causes COVID-19. Your body mounts an immune response against this, ready to protect you the next time you encounter the virus.
2. Moderna’s mRNA-1273 is in phase 3
The mRNA-1273 vaccine is developed by US company Moderna with the US National Institutes of Allergy and Infectious Diseases. The genetic material in this RNA-based vaccine also codes for the full spike protein.
3. Germany’s CVnCoV may have one or two doses
The vaccine has entered phase 2 trials, which is testing one and two doses.
4. TMV-083 uses a version of the measles vaccine
The vaccine uses a live-attenuated (weakened) measles vaccine to deliver and express the SARS-CoV-2 spike protein. The virus is still viable (live) but cannot cause disease.
5. AZD1222, the Oxford vaccine
AZD1222 is being developed by AstraZeneca with the University of Oxford. It uses a modified chimpanzee adenovirus to express the SARS-CoV-2 spike protein.
There have been good antibody responses against SARS-CoV-2 and no severe side effects in early clinical trials.
Australia has already entered an agreement to supply this vaccine should phase 3 trials prove successful. This deal is independent of the COVAX agreement.
6. Modified flu vaccine delivered up the nose
It will be the first nasal spray COVID-19 vaccine to be tested in humans.
The weakened flu virus delivers a part of the SARS-CoV-2 spike protein, which elicits a highly targeted immune response.
7. NVX-CoV2373 was tested in Australia
NVX-CoV2373 is a protein subunit vaccine developed by US company Novavax. It is made from purified pieces of the virus (full-length SARS-CoV-2 spike protein). It also contains an adjuvant — an extra molecule that boosts the immune response.
The vaccine was safe and stimulated a strong immune response in early clinical trials in Queensland and Victoria. Phase 3 trials are expected to start soon.
8. SCB-2019 is another protein subunit vaccine
SCB-2019 is another protein subunit vaccine, this time developed by Chinese company Clover Biopharmaceuticals. It is also based on the spike protein of SARS-CoV-2, purified in the lab, and also uses an adjuvant to stimulate the immune system.
Phase 1 trials have started in partnership with GlaxoSmithKline and Dynavax Technologies.
9. University of Queensland’s ‘molecular clamp’ vaccine
This vaccine is another protein subunit vaccine. It uses a “molecular clamp” to stabilise the SARS-CoV-2 spike protein in the configuration thought to elicit the best protective immune response.
A phase 1 trial, in partnership with CSL, started in July.
The Australian government has already entered into a deal to supply this vaccine should it progress through phase 3 trials. This deal is independent of the COVAX agreement.
Authors: Adam Taylor, Early Career Research Leader, Emerging Viruses, Inflammation and Therapeutics Group, Menzies Health Institute Queensland, Griffith University