CSL may manufacture mRNA and AstraZeneca vaccines that protect against new COVID-19 variants
Australia now has a second COVID-19 vaccine approved by the Therapeutic Goods Administration 9TGA).
The newly green-lit vaccine, which was developed by the University of Oxford and pharmaceutical company AstraZeneca, will be the one most Australians will get.
It will roll out “in early March, if not earlier”, according to Health Minister Greg Hunt at the announcement on Tuesday.
While nearly 4 million doses of the vaccine have been ordered from Europe, the lion’s share — some 50 million doses — will be manufactured at CSL’s facility in Broadmeadows, Melbourne, and mixed and packaged in nearby Parkville.
And while it might be the first locally made COVID-19 vaccine, it won’t be the last.
How the AstraZeneca vaccine works
- The AstraZeneca COVID-19 vaccine is a viral vector vaccine
- It enlists the help of a harmless virus, in this case a chimpanzee adenovirus ChAdOx1, to deliver a payload of genetic material into our cells
- The genetic material is in a ring of DNA and contains a blueprint to make the spike protein on the virus that causes COVID-19, SARS-CoV-2
- When it’s injected into our arm, the adenovirus slips the DNA ring into our cells
- Our cells “read” the DNA instructions and make spike proteins, then push them outside the cell to trigger an immune response
- After a time, the DNA ring is broken down and disposed of by our cells’ waste management system
Ahead of TGA approval, CSL has been making the AstraZeneca vaccine since November.
But as the coronavirus inevitably changes its genetic make-up and starts to evade the protection bestowed by vaccines, new versions of vaccines will need to be made too.
There is some early data which suggests the AstraZeneca vaccine may already offer less protection against the B.1.351 variant, which was initially found in South Africa.
AstraZeneca is developing an update to its vaccine to cover the B.1.351 variant, which it expects to have ready by September.
CSL’s chief scientific officer Andrew Nash said it was certainly possible to make modified vaccines locally.
“If they did [update the vaccine] and the evidence supported the use of that vaccine, then we may very well end up manufacturing it here,” he said.
CSL’s Broadmeadows facility can only make one vaccine at a time, he added, “so if we were making that variant vaccine, that’s the vaccine we’d be making, and it would depend on what strains the Australian population was at risk from at any given time”.
Despite new variants of the coronavirus emerging and spreading around the world, experts say it’s too early for Australia to switch vaccine strategies just yet.
Paul Griffin, professor of medicine at the University of Queensland, told ABC Science that if and when we need to do it, updating a vaccine would be “very simple”, and could take place over a matter of weeks or months.
Updating the AstraZeneca vaccine, for instance, consists of tweaking the DNA payload carried by the vaccine so our body constructs a slightly different spike protein that better matches the new variants, perhaps housed in a different virus.
“It’s not like starting over,” Professor Griffin said.
“We don’t have to go back to the very beginning and start again.”
Dr Nash did not rule out one day making other types of vaccines at CSL, including mRNA vaccines, such as the jab that was developed by Pfizer and given the TGA go-ahead last month.
These also use genetic material to elicit an immune response, but instead of a DNA ring inside an adenovirus, it is a string of messenger RNA — a slightly different type of genetic material that carries the message to make the spike protein — inside a fatty bubble.
And while making mRNA vaccines would require an overhaul of CSL’s production process, it’s not out of the question.
“We have an interest in the mRNA vaccines,” Dr Nash said.
“We’ve been watching the development and have been very pleased to see the way that they’ve been working.
“In our own research programs, we have some early work on those types of vaccines.”
How the company might start manufacturing mRNA vaccines for the current pandemic “is something we’re thinking about at the moment”, he added.
“No doubt down the track, CSL or perhaps someone else, I’m sure will eventually end up with some messenger RNA vaccine capacity here in Australia.
“I know that the federal government’s very interested in it, and there’s certainly a lot of discussion going on at the moment.”
Back in October, industry, science and technology minister Karen Andrews told ABC TV’s Insiders that the government had already conducted an audit of manufacturing facilities that could be enlisted to make mRNA vaccines, but it might take the best part of a year before they’re running.
Some Australian researchers believe we already have the capability to produce mRNA vaccines.
Colin Pouton, professor of pharmaceutical biology at Monash University, told Radio National’s Science Friction that with “a bit of teamwork and cooperation, it can be done“.