Pfizer, Moderna, AstraZeneca and Novavax: How COVID-19 vaccines are made
While we wait for today's figures around the states, lets take a look at how some of the major COVID-19 vaccines are made
Not only were these vaccines developed and tested at blistering pace — less than a year — but they're also being produced on a mass scale.
So how are they made?
Some production details are trade secrets.
But we do know that the three vaccine technologies we're likely to get in Australia don't incorporate, or even handle, the actual virus that causes COVID-19.
They instead use genetic instructions for a very specific part of the SARS-CoV-2 virus, the spike protein, which the virus uses to hook onto and infect our cells.
And while they all grow (or culture) cells and microbes in bioreactors as part of their production, they all do it differently.
Growing spike protein antigens
The most conventional style of vaccine is the protein subunit vaccine. The Novavax jab, as well as most of the jabs we get in childhood, fall under this umbrella.
These vaccines stimulate an immune response by directly delivering bits of the virus they're designed to protect us against.
Novovax production employs cell lines extracted from moths to manufacture its spike protein antigens.
The moth cells get their instructions to generate antigens from a virus that only infects insects.
mRNA wrapped in a greasy sheath
The newest style of vaccine are mRNA vaccines, such as those developed by Pfizer/BioNTech and Moderna.
These are fairly basic in structure, with just a strand of genetic material — that's the mRNA or messenger RNA — encapsulated in a protective envelope.
The message carried by the mRNA is a blueprint for our cells to construct copies of the SARS-CoV-2 spike protein, which we then use to train our immune system to recognise in case it sees the real thing down the track.
To make these vaccines, you first need a DNA template to make the mRNA.
Once you have your DNA templates, they're incubated in a cocktail of mRNA building blocks and enzymes.
The enzymes follow the template to construct mRNA strands.
Genes housed in a virus
The Oxford/AstraZeneca and Johnson & Johnson vaccines use a different type of virus, an adenovirus, to protect us against SARS-CoV-2.
These adenoviruses don't make us sick, but contain the genetic blueprint for the SARS-CoV-2 spike protein.
But unlike mRNA vaccines, where the instructions are in the form of a long, fragile single-stranded molecule, genetic instructions in adenovirus vaccines form part of a ring of double-stranded DNA.
This makes them much more stable than mRNA vaccines, and is why they can be stored at normal fridge temperatures.
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2021-02-03 20:17:00Z
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