“It takes a substantial quantity of finesse. It’s not like bacterial work the place it simply thrives – they’re fastidious. Artwork kind, that’s in all probability a good description,” mentioned Fraser Goodwin, CSL Behring’s senior manufacturing supervisor of upstream operations.
“It’s a organic system. Anybody who has youngsters is aware of, youngsters aren’t the identical. Each batch is completely different.”
However the manufacturing line is now buzzing, with the corporate anticipating to have the ability to ship a couple of million doses of vaccine per week when at full capability.
AstraZeneca’s vaccine is called a viral vector. The jab itself comprises a chimpanzee virus, modified in order that it can’t replicate inside our our bodies.
The chimp virus has been genetically manipulated so it carries the genetic code for SARS-CoV-2’s essential spike protein: the mobile harpoon the virus makes use of to contaminate our cells.
When the chimpanzee virus infects our cells, the cells learn the code and produce copies of the spike protein; our immune system then thinks it’s underneath assault from SARS-CoV-2 and generates antibodies.
In part three medical trials, these antibodies have proven between 62 and 90 per cent efficacy in preventing symptomatic infection. And the vaccine seems to supply near-total safety towards falling critically unwell or dying.
Producing the vaccine is a two-step course of. It begins life as two tiny frozen vials, shipped to CSL from AstraZeneca’s European laboratories.
One vial comprises the cells the vaccine will develop in. The opposite comprises the genetically modified virus that makes up the vaccine itself.
The cells – genetically modified human kidney embryo cells – are grown first. “You begin off with a millilitre, and you find yourself with 2000 litres. It’s a sluggish strategy of increasing from 1 millilitre to 10 millilitres to 50 millilitres,” mentioned Dr Anthony Stowers, senior vice chairman of recombinant product improvement at CSL.
The cells stay in a cloudy-pink soup, which comprises all of the vitamins they should develop. After about 4 or 5 weeks of progress, the cells are added to CSL’s big stainless-steel bioreactor – at the moment lined on high with a blue curtain to guard the light- delicate fluid inside.
Then the virus is launched.
The chimpanzee virus is genetically modified so it can’t replicate inside human cells. However the cells contained in the bioreactor have been modified as properly, permitting the virus to copy in them. Over a few days the virus infects the cells, replicates inside after which kills them, till the tank is crammed with virus.
Then the filtration course of begins. The pink goo is run via a sequence of filters to take away the useless cells and different waste merchandise, leaving simply the virus. The vaccine is now considerably full.
The liquid is then frozen in Cryovac lockers, and shipped the 22 kilometres between CSL’s Broadmeadows and Parkville websites. At Parkville, fill and end begins.
The vaccine spends a few week being examined to make sure it’s potent, pure and protected. “Then we really feel comfy cracking them open and beginning utilizing them,” mentioned Chris Larkins, senior vice-president of worldwide operations at CSL’s flu vaccine arm Seqirus.
“As soon as it’s thawed, the clock begins on a really quick timeframe. Each minute it’s not refrigerated needs to be recorded and tracked, and we have now very strict limits.”
The vaccine is added to a buffer, which comprises elements that stabilise it. It’s then filtered once more to make sure it’s sterile, earlier than the liquid is injected right into a glass vial – which has undergone its personal separate warmth therapy to sterilise it.
Every vial holds 6.5 millilitres, sufficient for 10 doses. The remainder of the bottle is made up of “grade A air” – “the cleanest pharmaceutical grade air,” Mr Larkins says. “And it is extremely troublesome to make.”
Earlier than the vials will be shipped to pharmacies, each vial – all 50 million of them – shall be inspected by hand by a specifically educated individual, searching for defects or points. Between 2 and 5 per cent of vials will get tossed at this stage, CSL expects.
Then the vials are shipped to the Therapeutic Items Administration – who will do their very own additional testing – earlier than it’s shipped the pharmacies, after which, in late March, injected into the arms of a grateful nation.
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Liam is The Age and Sydney Morning Herald’s science reporter