David Maher

ABC Listen.

Vaccines historically have been made out of eggs for decades.

It's a good way of making the flu vaccine because what we need to do at the very beginning of the process is to take a sample of the virus that matches the virus that's circulating in the community and make millions of them so that we can then purify it down to the proteins we want that will be the ultimate vaccine.

And we've done that for decades in eggs.

But as populations have grown and vaccination rates have improved and increased across the globe, just the amount of vaccines we need has gone up dramatically.

And some of the issues with eggs is that you need to have a very sophisticated and large supply chain of chickens.

And it got to a point in our facility here in Melbourne that we were getting almost half a million eggs every day.

needed to produce the vaccine.

And with that comes a lot of supply chain robustness issues.

We have to maintain huge flocks of birds.

They have to be at laying ages continually around the year.

And there's also biosecurity hazards that come into it, like the avian flu, which we've seen over the last few years.

Just over the last decade or so, we have developed a new and more modern way of producing the virus.

And we've done that using mammalian cells and a mammalian cell line

The cells come from a mammalian cell line that has been, again, around for a long time, I think since the 50s.

It's been used and grown in laboratories and used for the production of biologic materials and vaccine materials.

And we grow them up in large bioreactors, basically, up to 5,000 litre bioreactors at our facilities now.

And what you do once you've got the cells grown and ready, you then infect them with the virus.

And because they're a very close match to human cells, the virus multiplies dramatically, and that is the beginning of our process of producing the vaccine.

There's probably one other benefit to the cell-based manufacturing process, and that is with the egg-based manufacturing process, the virus sometimes needs to adapt slightly to grow in the avian cells.